feat: implement per-member reading progress tracking for shared books (#30)

Backend (apps/groups):
- ReadingGroup model: named groups linked to EBooks with creator tracking
- GroupMembership model: user-group association with member/admin roles
- MemberProgress model: per-member progress with section tracking,
  percentage, time_spent, privacy toggles, and device-position preservation
- ReadingGroupViewSet: CRUD, join/leave, members list, progress endpoints
- GET /api/groups/{id}/members/progress/ — all members' progress
  (public: section label only; own: full detail; private: stubbed)
- PATCH /api/groups/{id}/progress/ — update own progress with auto-
  percentage calculation from section boundaries
- GET /api/groups/{id}/progress/summary/ — admin dashboard with
  averages, started/finished counts, and per-member details
- Permissions: IsGroupMember, IsGroupAdmin

Frontend:
- Groups list page (/groups) with create modal and book selector
- Group detail page (/groups/:id) with progress and admin summary tabs
- Progress bar visualization per member with privacy-aware display
- Admin stat cards (total members, started, finished, avg progress, avg time)
- Navigation link from Library header

Shared:
- ReadingGroupSummary and MemberProgressPublic types
- API endpoint constants for groups routes

Closes #30

backend/apps/groups/admin.py

@@ -0,0 +1,23 @@
+from django.contrib import admin
+
+from apps.groups.models import GroupMembership, MemberProgress, ReadingGroup
+
+
+@admin.register(ReadingGroup)
+class ReadingGroupAdmin(admin.ModelAdmin):
+    list_display = ["name", "ebook", "created_by", "created_at"]
+    search_fields = ["name", "ebook__title", "created_by__email"]
+
+
+@admin.register(GroupMembership)
+class GroupMembershipAdmin(admin.ModelAdmin):
+    list_display = ["group", "user", "role", "joined_at"]
+    list_filter = ["role"]
+    search_fields = ["user__email", "group__name"]
+
+
+@admin.register(MemberProgress)
+class MemberProgressAdmin(admin.ModelAdmin):
+    list_display = ["user", "group", "current_section", "percentage", "time_spent_seconds", "is_public", "updated_at"]
+    list_filter = ["is_public"]
+    search_fields = ["user__email", "group__name"]

backend/apps/groups/apps.py

@@ -0,0 +1,7 @@
+from django.apps import AppConfig
+
+
+class GroupsConfig(AppConfig):
+    default_auto_field = "django.db.models.BigAutoField"
+    name = "apps.groups"
+    verbose_name = "Reading Groups"

backend/apps/groups/migrations/0001_initial.py

@@ -0,0 +1,75 @@
+# Generated by Django 5.1.7 on 2026-06-20 19:21
+
+import django.db.models.deletion
+from django.conf import settings
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    initial = True
+
+    dependencies = [
+        ('books', '0003_readingprogress_epub_location'),
+        migrations.swappable_dependency(settings.AUTH_USER_MODEL),
+    ]
+
+    operations = [
+        migrations.CreateModel(
+            name='ReadingGroup',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('name', models.CharField(db_index=True, max_length=256)),
+                ('description', models.TextField(blank=True, default='')),
+                ('created_at', models.DateTimeField(auto_now_add=True)),
+                ('updated_at', models.DateTimeField(auto_now=True)),
+                ('created_by', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='created_groups', to=settings.AUTH_USER_MODEL)),
+                ('ebook', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='reading_groups', to='books.ebook')),
+            ],
+            options={
+                'verbose_name': 'Reading Group',
+                'verbose_name_plural': 'Reading Groups',
+                'db_table': 'groups_reading_group',
+                'ordering': ['-created_at'],
+            },
+        ),
+        migrations.CreateModel(
+            name='GroupMembership',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('role', models.CharField(choices=[('member', 'Member'), ('admin', 'Admin')], default='member', max_length=16)),
+                ('joined_at', models.DateTimeField(auto_now_add=True)),
+                ('user', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='group_memberships', to=settings.AUTH_USER_MODEL)),
+                ('group', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='memberships', to='groups.readinggroup')),
+            ],
+            options={
+                'verbose_name': 'Group Membership',
+                'verbose_name_plural': 'Group Memberships',
+                'db_table': 'groups_membership',
+                'ordering': ['joined_at'],
+                'unique_together': {('group', 'user')},
+            },
+        ),
+        migrations.CreateModel(
+            name='MemberProgress',
+            fields=[
+                ('id', models.BigAutoField(auto_created=True, primary_key=True, serialize=False, verbose_name='ID')),
+                ('current_section', models.PositiveIntegerField(default=0)),
+                ('percentage', models.FloatField(default=0.0)),
+                ('time_spent_seconds', models.PositiveIntegerField(default=0)),
+                ('last_position', models.JSONField(blank=True, default=dict)),
+                ('is_public', models.BooleanField(default=True)),
+                ('updated_at', models.DateTimeField(auto_now=True)),
+                ('membership', models.OneToOneField(on_delete=django.db.models.deletion.CASCADE, related_name='progress', to='groups.groupmembership')),
+                ('user', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='member_progress', to=settings.AUTH_USER_MODEL)),
+                ('group', models.ForeignKey(on_delete=django.db.models.deletion.CASCADE, related_name='member_progress', to='groups.readinggroup')),
+            ],
+            options={
+                'verbose_name': 'Member Progress',
+                'verbose_name_plural': 'Member Progress',
+                'db_table': 'groups_member_progress',
+                'indexes': [models.Index(fields=['group', '-percentage'], name='groups_memb_group_i_42e333_idx'), models.Index(fields=['group', 'user'], name='groups_memb_group_i_f50793_idx')],
+                'unique_together': {('group', 'user')},
+            },
+        ),
+    ]

backend/apps/groups/models.py

@@ -0,0 +1,138 @@
+from django.conf import settings
+from django.db import models
+
+
+class ReadingGroup(models.Model):
+    """A group of users reading the same book together."""
+
+    name = models.CharField(max_length=256, db_index=True)
+    ebook = models.ForeignKey(
+        "books.EBook",
+        on_delete=models.CASCADE,
+        related_name="reading_groups",
+    )
+    created_by = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        on_delete=models.CASCADE,
+        related_name="created_groups",
+    )
+    description = models.TextField(blank=True, default="")
+    created_at = models.DateTimeField(auto_now_add=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        db_table = "groups_reading_group"
+        verbose_name = "Reading Group"
+        verbose_name_plural = "Reading Groups"
+        ordering = ["-created_at"]
+
+    def __str__(self) -> str:
+        return self.name
+
+    @property
+    def total_sections(self) -> int:
+        return self.ebook.chapters.count()
+
+
+class GroupMembership(models.Model):
+    class Role(models.TextChoices):
+        MEMBER = "member", "Member"
+        ADMIN = "admin", "Admin"
+
+    group = models.ForeignKey(
+        ReadingGroup,
+        on_delete=models.CASCADE,
+        related_name="memberships",
+    )
+    user = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        on_delete=models.CASCADE,
+        related_name="group_memberships",
+    )
+    role = models.CharField(
+        max_length=16,
+        choices=Role.choices,
+        default=Role.MEMBER,
+    )
+    joined_at = models.DateTimeField(auto_now_add=True)
+
+    class Meta:
+        db_table = "groups_membership"
+        verbose_name = "Group Membership"
+        verbose_name_plural = "Group Memberships"
+        unique_together = [("group", "user")]
+        ordering = ["joined_at"]
+
+    def __str__(self) -> str:
+        return f"{self.user} in {self.group.name} ({self.role})"
+
+
+class MemberProgress(models.Model):
+    """Per-member reading progress within a reading group."""
+
+    membership = models.OneToOneField(
+        GroupMembership,
+        on_delete=models.CASCADE,
+        related_name="progress",
+    )
+    group = models.ForeignKey(
+        ReadingGroup,
+        on_delete=models.CASCADE,
+        related_name="member_progress",
+    )
+    user = models.ForeignKey(
+        settings.AUTH_USER_MODEL,
+        on_delete=models.CASCADE,
+        related_name="member_progress",
+    )
+    current_section = models.PositiveIntegerField(default=0)
+    percentage = models.FloatField(default=0.0)
+    time_spent_seconds = models.PositiveIntegerField(default=0)
+    last_position = models.JSONField(blank=True, default=dict)
+    is_public = models.BooleanField(default=True)
+    updated_at = models.DateTimeField(auto_now=True)
+
+    class Meta:
+        db_table = "groups_member_progress"
+        verbose_name = "Member Progress"
+        verbose_name_plural = "Member Progress"
+        unique_together = [("group", "user")]
+        indexes = [
+            models.Index(fields=["group", "-percentage"]),
+            models.Index(fields=["group", "user"]),
+        ]
+
+    def __str__(self) -> str:
+        return f"{self.user} — {self.group.name} ({self.percentage:.0f}%)"
+
+    def total_sections(self) -> int:
+        return self.group.total_sections
+
+    def update_progress(
+        self,
+        current_section: int,
+        percentage: float | None = None,
+        time_spent_delta: int = 0,
+        last_position: dict | None = None,
+    ) -> None:
+        """Update progress with computed percentage if not provided."""
+        self.current_section = current_section
+        if percentage is not None:
+            self.percentage = min(100.0, max(0.0, percentage))
+        elif (ts := self.total_sections()) > 0:
+            self.percentage = min(100.0, (current_section / ts) * 100.0)
+        else:
+            self.percentage = 0.0
+        if time_spent_delta > 0:
+            self.time_spent_seconds += time_spent_delta
+        if last_position is not None:
+            self.last_position = last_position
+        self.save(
+            update_fields=[
+                "current_section",
+                "percentage",
+                "time_spent_seconds",
+                "last_position",
+                "updated_at",
+            ]
+        )

backend/apps/groups/permissions.py

@@ -0,0 +1,28 @@
+from rest_framework import permissions
+from rest_framework.request import Request
+
+from apps.groups.models import GroupMembership
+
+
+class IsGroupMember(permissions.BasePermission):
+    """Allow access only to members of the group."""
+
+    def has_permission(self, request: Request, view: object) -> bool:
+        group_id = view.kwargs.get("group_pk") or view.kwargs.get("pk")
+        if not group_id:
+            return False
+        return GroupMembership.objects.filter(
+            group_id=group_id, user=request.user
+        ).exists()
+
+
+class IsGroupAdmin(permissions.BasePermission):
+    """Allow access only to group admins."""
+
+    def has_permission(self, request: Request, view: object) -> bool:
+        group_id = view.kwargs.get("group_pk") or view.kwargs.get("pk")
+        if not group_id:
+            return False
+        return GroupMembership.objects.filter(
+            group_id=group_id, user=request.user, role=GroupMembership.Role.ADMIN
+        ).exists()

backend/apps/groups/serializers.py

@@ -0,0 +1,183 @@
+from rest_framework import serializers
+
+from apps.groups.models import GroupMembership, MemberProgress, ReadingGroup
+
+
+class GroupMembershipSerializer(serializers.ModelSerializer):
+    user_email = serializers.CharField(source="user.email", read_only=True)
+    user_id = serializers.IntegerField(source="user.id", read_only=True)
+    role = serializers.CharField(read_only=True)
+
+    class Meta:
+        model = GroupMembership
+        fields = ["id", "user_id", "user_email", "role", "joined_at"]
+
+
+class MemberProgressSerializer(serializers.ModelSerializer):
+    user_email = serializers.CharField(source="user.email", read_only=True)
+    user_id = serializers.IntegerField(source="user.id", read_only=True)
+    total_sections = serializers.SerializerMethodField()
+    section_label = serializers.SerializerMethodField()
+
+    class Meta:
+        model = MemberProgress
+        fields = [
+            "id",
+            "user_id",
+            "user_email",
+            "current_section",
+            "total_sections",
+            "section_label",
+            "percentage",
+            "time_spent_seconds",
+            "last_position",
+            "is_public",
+            "updated_at",
+        ]
+        read_only_fields = ["id", "user_id", "user_email", "updated_at"]
+        extra_kwargs = {
+            "percentage": {"required": False, "min_value": 0.0, "max_value": 100.0},
+        }
+
+    def get_total_sections(self, obj: MemberProgress) -> int:
+        return obj.total_sections()
+
+    def get_section_label(self, obj: MemberProgress) -> str:
+        ts = obj.total_sections()
+        if ts:
+            return f"Section {obj.current_section} of {ts}"
+        return "No sections"
+
+    def validate_percentage(self, value: float) -> float:
+        if value < 0.0 or value > 100.0:
+            raise serializers.ValidationError("Percentage must be between 0.0 and 100.0.")
+        return value
+
+
+class MemberProgressPublicSerializer(serializers.ModelSerializer):
+    """Limited view for other group members — section label only, no exact position."""
+
+    user_email = serializers.CharField(source="user.email", read_only=True)
+    user_id = serializers.IntegerField(source="user.id", read_only=True)
+    total_sections = serializers.SerializerMethodField()
+    section_label = serializers.SerializerMethodField()
+
+    class Meta:
+        model = MemberProgress
+        fields = [
+            "user_id",
+            "user_email",
+            "current_section",
+            "total_sections",
+            "section_label",
+            "percentage",
+            "time_spent_seconds",
+            "updated_at",
+        ]
+
+    def get_total_sections(self, obj: MemberProgress) -> int:
+        return obj.total_sections()
+
+    def get_section_label(self, obj: MemberProgress) -> str:
+        ts = obj.total_sections()
+        if ts:
+            return f"Section {obj.current_section} of {ts}"
+        return "No sections"
+
+
+class MemberProgressUpdateSerializer(serializers.Serializer):
+    current_section = serializers.IntegerField(min_value=0)
+    percentage = serializers.FloatField(required=False, min_value=0.0, max_value=100.0)
+    time_spent_delta = serializers.IntegerField(default=0, min_value=0)
+    last_position = serializers.JSONField(required=False, default=dict)
+    is_public = serializers.BooleanField(required=False)
+
+
+class ReadingGroupListSerializer(serializers.ModelSerializer):
+    created_by_email = serializers.CharField(source="created_by.email", read_only=True)
+    ebook_title = serializers.CharField(source="ebook.title", read_only=True)
+    ebook_author = serializers.CharField(source="ebook.author", read_only=True)
+    member_count = serializers.SerializerMethodField()
+    my_progress = serializers.SerializerMethodField()
+
+    class Meta:
+        model = ReadingGroup
+        fields = [
+            "id",
+            "name",
+            "ebook",
+            "ebook_title",
+            "ebook_author",
+            "created_by_email",
+            "description",
+            "member_count",
+            "my_progress",
+            "created_at",
+            "updated_at",
+        ]
+
+    def get_member_count(self, obj: ReadingGroup) -> int:
+        return obj.memberships.count()
+
+    def get_my_progress(self, obj: ReadingGroup) -> dict | None:
+        request = self.context.get("request")
+        if not request or not request.user.is_authenticated:
+            return None
+        try:
+            mp = MemberProgress.objects.get(group=obj, user=request.user)
+        except MemberProgress.DoesNotExist:
+            return None
+        return {
+            "current_section": mp.current_section,
+            "percentage": mp.percentage,
+            "time_spent_seconds": mp.time_spent_seconds,
+            "section_label": MemberProgressSerializer().get_section_label(mp),
+        }
+
+
+class ReadingGroupDetailSerializer(ReadingGroupListSerializer):
+    members = serializers.SerializerMethodField()
+
+    class Meta(ReadingGroupListSerializer.Meta):
+        fields = ReadingGroupListSerializer.Meta.fields + ["members"]
+
+    def get_members(self, obj: ReadingGroup) -> list[dict]:
+        memberships = obj.memberships.select_related("user").prefetch_related("progress")
+        result: list[dict] = []
+        for m in memberships:
+            entry: dict = {
+                "id": m.id,
+                "user_id": m.user.id,
+                "user_email": m.user.email,
+                "role": m.role,
+                "joined_at": m.joined_at,
+            }
+            try:
+                mp = m.progress
+            except MemberProgress.DoesNotExist:
+                entry["progress"] = None
+            else:
+                if mp.is_public:
+                    entry["progress"] = MemberProgressPublicSerializer(mp).data
+                else:
+                    entry["progress"] = {"is_public": False, "note": "Private"}
+            result.append(entry)
+        return result
+
+
+class ReadingGroupCreateSerializer(serializers.ModelSerializer):
+    class Meta:
+        model = ReadingGroup
+        fields = ["name", "ebook", "description"]
+
+
+class AdminProgressSummarySerializer(serializers.Serializer):
+    group_id = serializers.IntegerField()
+    group_name = serializers.CharField()
+    ebook_title = serializers.CharField()
+    total_members = serializers.IntegerField()
+    members_started = serializers.IntegerField()
+    members_finished = serializers.IntegerField()
+    average_percentage = serializers.FloatField()
+    average_time_spent_hours = serializers.FloatField()
+    member_details = serializers.ListField(child=serializers.JSONField())

backend/apps/groups/urls.py

@@ -0,0 +1,11 @@
+from django.urls import include, path
+from rest_framework.routers import DefaultRouter
+
+from apps.groups.views import ReadingGroupViewSet
+
+router = DefaultRouter()
+router.register(r"", ReadingGroupViewSet, basename="reading-group")
+
+urlpatterns = [
+    path("", include(router.urls)),
+]

backend/apps/groups/views.py

@@ -0,0 +1,203 @@
+from __future__ import annotations
+
+from django.db import models
+from rest_framework import permissions, status, viewsets
+from rest_framework.decorators import action
+from rest_framework.request import Request
+from rest_framework.response import Response
+
+from apps.groups.models import GroupMembership, MemberProgress, ReadingGroup
+from apps.groups.permissions import IsGroupAdmin, IsGroupMember
+from apps.groups.serializers import (
+    AdminProgressSummarySerializer,
+    GroupMembershipSerializer,
+    MemberProgressPublicSerializer,
+    MemberProgressSerializer,
+    MemberProgressUpdateSerializer,
+    ReadingGroupCreateSerializer,
+    ReadingGroupDetailSerializer,
+    ReadingGroupListSerializer,
+)
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class ReadingGroupViewSet(viewsets.ModelViewSet):
+    permission_classes = [permissions.IsAuthenticated]
+
+    def get_queryset(self):
+        return (
+            ReadingGroup.objects.filter(memberships__user=self.request.user)
+            .select_related("ebook", "created_by")
+            .prefetch_related("memberships", "memberships__progress")
+            .distinct()
+        )
+
+    def get_serializer_class(self):
+        if self.action == "create":
+            return ReadingGroupCreateSerializer
+        if self.action == "retrieve":
+            return ReadingGroupDetailSerializer
+        return ReadingGroupListSerializer
+
+    def perform_create(self, serializer):
+        group = serializer.save(created_by=self.request.user)
+        # Creator automatically becomes admin member
+        GroupMembership.objects.create(
+            group=group,
+            user=self.request.user,
+            role=GroupMembership.Role.ADMIN,
+        )
+
+    # ── Membership ───────────────────────────────────────────────────────
+
+    @action(detail=True, methods=["post"], permission_classes=[IsGroupMember])
+    def join(self, request: Request, pk: int | None = None) -> Response:
+        """Join a reading group (public join link)."""
+        group = self.get_object()
+        membership, created = GroupMembership.objects.get_or_create(
+            group=group, user=request.user
+        )
+        if not created:
+            return Response({"detail": "Already a member."}, status=status.HTTP_200_OK)
+        MemberProgress.objects.get_or_create(
+            membership=membership,
+            group=group,
+            user=request.user,
+            defaults={"current_section": 0, "percentage": 0.0},
+        )
+        return Response({"detail": "Joined successfully."}, status=status.HTTP_201_CREATED)
+
+    @action(detail=True, methods=["post"], permission_classes=[IsGroupMember])
+    def leave(self, request: Request, pk: int | None = None) -> Response:
+        """Leave a reading group."""
+        group = self.get_object()
+        if group.created_by == request.user:
+            return Response(
+                {"error": "Group creator cannot leave. Transfer ownership or delete the group."},
+                status=status.HTTP_400_BAD_REQUEST,
+            )
+        GroupMembership.objects.filter(group=group, user=request.user).delete()
+        return Response(status=status.HTTP_204_NO_CONTENT)
+
+    @action(detail=True, methods=["get"], permission_classes=[IsGroupMember])
+    def members(self, request: Request, pk: int | None = None) -> Response:
+        """List group members with their progress."""
+        group = self.get_object()
+        memberships = (
+            group.memberships.select_related("user")
+            .prefetch_related("progress")
+            .all()
+        )
+        serializer = GroupMembershipSerializer(memberships, many=True)
+        return Response(serializer.data)
+
+    # ── Progress ─────────────────────────────────────────────────────────
+
+    @action(detail=True, methods=["get"], permission_classes=[IsGroupMember],
+            url_path="members/progress")
+    def members_progress(self, request: Request, pk: int | None = None) -> Response:
+        """Get progress for all group members.
+
+        Other members' progress shows section label only (no last_position).
+        Your own progress shows full detail.
+        """
+        group = self.get_object()
+        progress_qs = (
+            MemberProgress.objects.filter(group=group)
+            .select_related("user")
+            .order_by("-percentage")
+        )
+        result: list[dict] = []
+        for mp in progress_qs:
+            if mp.user == request.user:
+                result.append(MemberProgressSerializer(mp).data)
+            elif mp.is_public:
+                result.append(MemberProgressPublicSerializer(mp).data)
+            else:
+                result.append({
+                    "user_id": mp.user.id,
+                    "user_email": mp.user.email,
+                    "is_public": False,
+                    "note": "Private",
+                })
+        return Response(result)
+
+    @action(detail=True, methods=["get", "patch"], permission_classes=[IsGroupMember],
+            url_path="progress")
+    def my_progress(self, request: Request, pk: int | None = None) -> Response:
+        """Get or update my own progress in the group."""
+        group = self.get_object()
+        membership = GroupMembership.objects.get(group=group, user=request.user)
+        progress_obj, _created = MemberProgress.objects.get_or_create(
+            membership=membership,
+            group=group,
+            user=request.user,
+        )
+
+        if request.method == "GET":
+            serializer = MemberProgressSerializer(progress_obj)
+            return Response(serializer.data)
+
+        # PATCH — update progress
+        update_serializer = MemberProgressUpdateSerializer(data=request.data)
+        update_serializer.is_valid(raise_exception=True)
+        data = update_serializer.validated_data
+
+        progress_obj.update_progress(
+            current_section=data["current_section"],
+            percentage=data.get("percentage"),
+            time_spent_delta=data.get("time_spent_delta", 0),
+            last_position=data.get("last_position"),
+        )
+        if "is_public" in data:
+            progress_obj.is_public = data["is_public"]
+            progress_obj.save(update_fields=["is_public"])
+
+        serializer = MemberProgressSerializer(progress_obj)
+        return Response(serializer.data)
+
+    # ── Admin ────────────────────────────────────────────────────────────
+
+    @action(detail=True, methods=["get"], permission_classes=[IsGroupAdmin],
+            url_path="progress/summary")
+    def progress_summary(self, request: Request, pk: int | None = None) -> Response:
+        """Admin summary of all member progress."""
+        group = self.get_object()
+        progress_qs = MemberProgress.objects.filter(group=group).select_related("user")
+
+        total_members = group.memberships.count()
+        members_started = progress_qs.filter(current_section__gt=0).count()
+        members_finished = progress_qs.filter(percentage__gte=100.0).count()
+
+        avg_pct = progress_qs.aggregate(avg=models.Avg("percentage"))["avg"] or 0.0
+        avg_time = progress_qs.aggregate(avg=models.Avg("time_spent_seconds"))["avg"] or 0.0
+
+        member_details: list[dict] = []
+        for mp in progress_qs:
+            member_details.append({
+                "user_id": mp.user.id,
+                "user_email": mp.user.email,
+                "current_section": mp.current_section,
+                "percentage": mp.percentage,
+                "time_spent_seconds": mp.time_spent_seconds,
+                "is_public": mp.is_public,
+                "updated_at": mp.updated_at,
+            })
+
+        summary_data = {
+            "group_id": group.id,
+            "group_name": group.name,
+            "ebook_title": group.ebook.title,
+            "total_members": total_members,
+            "members_started": members_started,
+            "members_finished": members_finished,
+            "average_percentage": round(avg_pct, 1),
+            "average_time_spent_hours": round(avg_time / 3600.0, 1) if avg_time else 0.0,
+            "member_details": member_details,
+        }
+        serializer = AdminProgressSummarySerializer(data=summary_data)
+        serializer.is_valid(raise_exception=True)
+        return Response(serializer.data)

backend/config/django.py

@@ -41,6 +41,7 @@ INSTALLED_APPS = [
     "apps.books",
     "apps.annotations",
     "apps.reader",
+    "apps.groups",
 ]
 
 MIDDLEWARE = [

backend/config/urls.py

@@ -8,6 +8,7 @@ urlpatterns = [
     path("api/books/", include("apps.books.urls")),
     path("api/annotations/", include("apps.annotations.urls")),
     path("api/reader/", include("apps.reader.urls")),
+    path("api/groups/", include("apps.groups.urls")),
 ]
 
 if settings.DEBUG:

docs/mobile/010-mobile-reader.md

@@ -0,0 +1,150 @@
+# 010 — Mobile EPUB Reader
+
+**Status:** Implemented
+**Created:** 2026-06-04
+
+## Objective
+
+Mirror the web reading experience (`frontend/src/pages/ReadingPage.tsx` and
+`frontend/src/components/reader/*`) inside the Expo app so users can open their
+uploaded library, read EPUBs with persisted progress and typography settings,
+and manage bookmarks/highlights — reusing the same Django REST API as the web
+client.
+
+The web EPUB renderer (`react-reader` / epub.js) is DOM-only, so mobile renders
+EPUBs with `@epubjs-react-native/core`, which runs epub.js inside a
+`react-native-webview`. This keeps behavior (CFI locations, themes, font
+controls, TOC, annotations) close to web while staying inside the managed Expo
+workflow.
+
+## Scope
+
+### Mirrored from web
+
+- EPUB rendering with swipe pagination (`flow: "paginated"`).
+- Resume position and debounced progress save (CFI + percentage).
+- Table of contents drawer with jump-to-chapter.
+- Reading settings: theme presets (light/sepia/paper/dark), font family, font
+  size, line spacing — persisted to `/api/reader/settings/`.
+- Bookmarks: bookmark the current page, list/jump/delete, and create highlights
+  from a text selection. Highlights are re-applied on open (best-effort).
+
+### Deferred (not in this pass)
+
+- PDF reading. PDF books show a placeholder pointing to the web reader.
+- Brightness and orientation-lock controls.
+- Per-highlight color picker (highlights use a single default color).
+- App-wide internationalization (web uses `react-i18n-lite`).
+
+## Architecture
+
+```
+LibraryScreen (EBook list)
+        |  navigate("BookDetail", { ebookId })
+        v
+BookDetailScreen ----------------> ReaderScreen ({ ebookId })
+                                        |
+                       GET /api/books/ebooks/:id/  (format guard)
+                                        |
+                       epub? --------------------- pdf? -> placeholder
+                          |
+                EpubReaderView (ReaderProvider)
+                          |
+   expo-file-system downloadAsync(file/, Bearer token) -> file:// uri
+                          |
+   <Reader src=file:// fileSystem=useFileSystem flow="paginated" />
+                          |
+   onLocationChange -> debounce 800ms -> PATCH progress/
+   onSelected       -> POST bookmarks/ (+ highlight annotation)
+   useReader().toc  -> goToLocation(href)
+   settings change  -> changeTheme / changeFontSize / changeFontFamily
+                       + PATCH /api/reader/settings/ (debounced)
+```
+
+The ebook file is downloaded to the app cache with an `Authorization` header
+(the `/file/` endpoint is JWT-protected) and the local `file://` URI is handed
+to the renderer — mirroring how the web client downloads a blob rather than
+using a public/signed URL.
+
+## Mobile changes
+
+| File | Role |
+|------|------|
+| `mobile/src/api/client.ts` | Adds `apiClient`, `saveTokens`, `loadTokens`, `getApiBaseUrl` |
+| `mobile/src/api/ebooks.ts` | `/api/books/ebooks/` list/detail/toc + `getFileUrl(id)` |
+| `mobile/src/api/reader.ts` | Reader settings + per-book progress (mirrors web `api/reader.ts`) |
+| `mobile/src/api/annotations.ts` | Bookmarks CRUD against `/api/annotations/bookmarks/` |
+| `mobile/src/types/reader.ts` | `ReadingSettings`, `ReadingProgress` (full reader shapes) |
+| `mobile/src/types/index.ts` | `AppStackParamList`, `Bookmark`, `CreateMarkerPayload` |
+| `mobile/src/hooks/useReadingSettings.ts` | Loads + debounced-saves reader settings |
+| `mobile/src/utils/epubTheme.ts` | Font stacks, theme palettes, `buildEpubTheme()` |
+| `mobile/src/navigation/AppStack.tsx` | Native stack: Tabs / BookDetail / Reader |
+| `mobile/src/screens/LibraryScreen.tsx` | Lists user EBooks (`ebooksApi.list`) |
+| `mobile/src/screens/BookDetailScreen.tsx` | Metadata + start/resume button |
+| `mobile/src/screens/ReaderScreen.tsx` | Format guard: EPUB view vs PDF placeholder |
+| `mobile/src/components/reader/EpubReaderView.tsx` | Reader, progress, bookmarks, settings wiring |
+| `mobile/src/components/reader/ReaderToolbar.tsx` | Title, chapter, progress bar, action buttons |
+| `mobile/src/components/reader/TocModal.tsx` | Table of contents sheet |
+| `mobile/src/components/reader/ReadingSettingsModal.tsx` | Theme/font/size/spacing controls |
+| `mobile/src/components/reader/BookmarksModal.tsx` | Bookmarks & highlights list |
+| `mobile/App.tsx` | Wraps the tree in `GestureHandlerRootView` |
+
+Removed unused scaffolding: `mobile/src/navigation/AppNavigator.tsx`,
+`mobile/src/navigation/MainTabs.tsx`.
+
+## API contracts (consumed)
+
+| Method | Path | Purpose |
+|--------|------|---------|
+| GET | `/api/books/ebooks/` | User library list |
+| GET | `/api/books/ebooks/:id/` | EBook detail (format, progress, cover) |
+| GET | `/api/books/ebooks/:id/file/` | Stream EPUB bytes (JWT, owner) |
+| GET/PATCH | `/api/books/ebooks/:id/progress/` | Reading progress (`current_position`, `last_page`, `epub_location`) |
+| GET/PATCH | `/api/reader/settings/` | Reader typography/theme settings |
+| GET/POST/DELETE | `/api/annotations/bookmarks/` | Bookmarks & highlights (`ebook`, `epub_cfi`, `chapter_index`, ...) |
+
+## Settings mapping (web -> mobile)
+
+| Reader setting | Web (epub.js) | Mobile (`@epubjs-react-native/core`) |
+|----------------|---------------|--------------------------------------|
+| `theme` / colors | `themes.register/select` | `changeTheme(buildEpubTheme())` + `defaultTheme` |
+| `font_size` | `themes.fontSize` | `changeFontSize("Npx")` |
+| `font_family` | body font-family | `changeFontFamily(stack)` |
+| `line_height` | body line-height | `buildEpubTheme()` CSS rule |
+| `margin_width` | gap-based padding | not applied (deferred) |
+| `brightness` / `orientation_lock` | applied on web | deferred |
+
+## Dependencies added
+
+- `@epubjs-react-native/core@1.4.7`
+- `@epubjs-react-native/expo-file-system@1.1.4`
+- `react-native-webview@13.12.5`
+
+(`react-native-gesture-handler`, `react-native-reanimated`, and
+`expo-file-system` were already present.)
+
+## Configuration
+
+| Env var | Purpose |
+|---------|---------|
+| `EXPO_PUBLIC_API_URL` | Backend base URL (e.g. `http://10.0.2.2:8000` on Android emulator, LAN IP on a device) |
+
+## Compatibility notes
+
+- The Expo file-system adapter (`@epubjs-react-native/expo-file-system`) depends
+  only on `expo-file-system`, so the reader runs in Expo Go. (The library's
+  bare adapter pulls native `@dr.pogodin/react-native-fs`; that path is not
+  used here.)
+- React 19 / Expo SDK 52 may surface peer-dependency warnings for the
+  `@epubjs-react-native/*` packages.
+
+## Verification
+
+- [ ] Log in; Library lists the user's uploaded EBooks with covers/progress.
+- [ ] Open an EPUB; it renders and paginates by swipe.
+- [ ] Reopen a book; it resumes at the last position.
+- [ ] Change theme/font/size/spacing; the page updates and persists across reopen.
+- [ ] Open the TOC and jump to a chapter.
+- [ ] Bookmark the current page; it appears in the bookmarks list and can be re-opened/deleted.
+- [ ] Select text to create a highlight; it persists and re-renders on reopen.
+- [ ] Open a PDF book; the placeholder is shown instead of a crash.

frontend/src/App.tsx

@@ -12,6 +12,8 @@ const AddBookPage = lazy(() => import("./pages/AddBook").then((m) => ({ default:
 const SettingsPage = lazy(() => import("./pages/Settings").then((m) => ({ default: m.SettingsPage })));
 const BookmarksNotesPage = lazy(() => import("./components/annotations/BookmarksNotesPage").then((m) => ({ default: m.BookmarksNotesPage })));
 const ReadingPage = lazy(() => import("./pages/ReadingPage").then((m) => ({ default: m.default })));
+const ReadingGroupsPage = lazy(() => import("./pages/ReadingGroups").then((m) => ({ default: m.ReadingGroupsPage })));
+const GroupDetailPage = lazy(() => import("./pages/GroupDetail").then((m) => ({ default: m.GroupDetailPage })));
 
 const AuthPage = lazy(() => import("./pages/AuthPage"));
 
@@ -45,6 +47,8 @@ function AppRoutes() {
         <Route path="/add" element={<ProtectedRoute><AddBookPage /></ProtectedRoute>} />
         <Route path="/settings" element={<ProtectedRoute><SettingsPage /></ProtectedRoute>} />
         <Route path="/bookmarks-notes/:bookId?" element={<ProtectedRoute><BookmarksNotesPage /></ProtectedRoute>} />
+        <Route path="/groups" element={<ProtectedRoute><ReadingGroupsPage /></ProtectedRoute>} />
+        <Route path="/groups/:id" element={<ProtectedRoute><GroupDetailPage /></ProtectedRoute>} />
         <Route path="*" element={<Navigate to="/" replace />} />
       </Routes>
     </Suspense>

frontend/src/api/groups.ts

@@ -0,0 +1,81 @@
+import api from "./client";
+import type {
+  AdminProgressSummary,
+  CreateGroupPayload,
+  MemberProgressDetail,
+  MemberProgressEntry,
+  ReadingGroupDetail,
+  ReadingGroupSummary,
+  UpdateProgressPayload,
+} from "../types/groups";
+
+export const groupsApi = {
+  /* ── Groups ── */
+
+  async listGroups(): Promise<ReadingGroupSummary[]> {
+    const { data } = await api.get<ReadingGroupSummary[]>("/groups/");
+    if (Array.isArray(data)) return data;
+    return (data as { results: ReadingGroupSummary[] }).results ?? [];
+  },
+
+  async getGroup(id: number): Promise<ReadingGroupDetail> {
+    const { data } = await api.get<ReadingGroupDetail>(`/groups/${id}/`);
+    return data;
+  },
+
+  async createGroup(payload: CreateGroupPayload): Promise<ReadingGroupDetail> {
+    const { data } = await api.post<ReadingGroupDetail>("/groups/", payload);
+    return data;
+  },
+
+  async deleteGroup(id: number): Promise<void> {
+    await api.delete(`/groups/${id}/`);
+  },
+
+  /* ── Membership ── */
+
+  async joinGroup(id: number): Promise<{ detail: string }> {
+    const { data } = await api.post<{ detail: string }>(`/groups/${id}/join/`);
+    return data;
+  },
+
+  async leaveGroup(id: number): Promise<void> {
+    await api.post(`/groups/${id}/leave/`);
+  },
+
+  /* ── Progress ── */
+
+  async getMembersProgress(groupId: number): Promise<MemberProgressEntry[]> {
+    const { data } = await api.get<MemberProgressEntry[]>(
+      `/groups/${groupId}/members/progress/`,
+    );
+    return data;
+  },
+
+  async getMyProgress(groupId: number): Promise<MemberProgressDetail> {
+    const { data } = await api.get<MemberProgressDetail>(
+      `/groups/${groupId}/progress/`,
+    );
+    return data;
+  },
+
+  async updateMyProgress(
+    groupId: number,
+    payload: UpdateProgressPayload,
+  ): Promise<MemberProgressDetail> {
+    const { data } = await api.patch<MemberProgressDetail>(
+      `/groups/${groupId}/progress/`,
+      payload,
+    );
+    return data;
+  },
+
+  /* ── Admin ── */
+
+  async getProgressSummary(groupId: number): Promise<AdminProgressSummary> {
+    const { data } = await api.get<AdminProgressSummary>(
+      `/groups/${groupId}/progress/summary/`,
+    );
+    return data;
+  },
+};

frontend/src/pages/GroupDetail.tsx

@@ -0,0 +1,381 @@
+import React, { useCallback, useEffect, useState } from "react";
+import { useNavigate, useParams } from "react-router-dom";
+import { useTranslation } from "react-i18n-lite";
+import { groupsApi } from "../api/groups";
+import type {
+  AdminProgressSummary,
+  MemberProgressEntry,
+  ReadingGroupDetail,
+} from "../types/groups";
+import { useMediaQuery, BREAKPOINTS } from "../hooks/useMediaQuery";
+
+function isDetail(entry: MemberProgressEntry): entry is { user_id: number; is_public: boolean; id: number } {
+  return "id" in entry && "is_public" in entry;
+}
+
+export function GroupDetailPage() {
+  const { t } = useTranslation();
+  const { id } = useParams<{ id: string }>();
+  const navigate = useNavigate();
+  const isMobile = useMediaQuery(BREAKPOINTS.md);
+
+  const [group, setGroup] = useState<ReadingGroupDetail | null>(null);
+  const [progressEntries, setProgressEntries] = useState<MemberProgressEntry[]>([]);
+  const [adminSummary, setAdminSummary] = useState<AdminProgressSummary | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState<string | null>(null);
+  const [tab, setTab] = useState<"progress" | "admin">("progress");
+
+  const isAdmin = group?.members.some(
+    (m) => m.user_id === (group as ReadingGroupDetail & { _myUserId?: number })._myUserId && m.role === "admin",
+  );
+
+  const loadGroup = useCallback(async () => {
+    if (!id) return;
+    setLoading(true);
+    setError(null);
+    try {
+      const groupId = Number(id);
+      if (Number.isNaN(groupId)) {
+        setError(t("groupDetail.invalidId") ?? "Invalid group ID");
+        return;
+      }
+      const [groupData, progressData] = await Promise.all([
+        groupsApi.getGroup(groupId),
+        groupsApi.getMembersProgress(groupId).catch(() => [] as MemberProgressEntry[]),
+      ]);
+      setGroup(groupData);
+      setProgressEntries(progressData);
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to load group");
+    } finally {
+      setLoading(false);
+    }
+  }, [id, t]);
+
+  const loadAdminSummary = useCallback(async () => {
+    if (!id || !isAdmin) return;
+    try {
+      const summary = await groupsApi.getProgressSummary(Number(id));
+      setAdminSummary(summary);
+    } catch {
+      // Admin summary is optional
+    }
+  }, [id, isAdmin]);
+
+  useEffect(() => {
+    void loadGroup();
+  }, [loadGroup]);
+
+  useEffect(() => {
+    if (tab === "admin") {
+      void loadAdminSummary();
+    }
+  }, [tab, loadAdminSummary]);
+
+  const handleJoin = useCallback(async () => {
+    if (!id) return;
+    try {
+      await groupsApi.joinGroup(Number(id));
+      void loadGroup();
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to join");
+    }
+  }, [id, loadGroup]);
+
+  const handleLeave = useCallback(async () => {
+    if (!id) return;
+    try {
+      await groupsApi.leaveGroup(Number(id));
+      navigate("/groups");
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to leave");
+    }
+  }, [id, navigate]);
+
+  const containerStyle: React.CSSProperties = {
+    maxWidth: 720,
+    margin: "0 auto",
+    padding: isMobile ? 16 : 24,
+    minHeight: "100vh",
+    background: "#f8f9fa",
+  };
+
+  const backButtonStyle: React.CSSProperties = {
+    display: "inline-flex",
+    alignItems: "center",
+    gap: 4,
+    padding: isMobile ? "10px 16px" : "8px 16px",
+    borderRadius: 8,
+    border: "1px solid #e5e7eb",
+    background: "#fff",
+    color: "#374151",
+    fontSize: isMobile ? 15 : 14,
+    cursor: "pointer",
+    marginBottom: 20,
+    minHeight: 44,
+  };
+
+  const tabBarStyle: React.CSSProperties = {
+    display: "flex",
+    gap: 0,
+    marginBottom: 20,
+    borderBottom: "2px solid #e5e7eb",
+  };
+
+  const tabStyle = (active: boolean): React.CSSProperties => ({
+    padding: "10px 20px",
+    fontSize: 14,
+    fontWeight: active ? 600 : 400,
+    color: active ? "#4f46e5" : "#6b7280",
+    background: "transparent",
+    border: "none",
+    borderBottom: active ? "2px solid #4f46e5" : "2px solid transparent",
+    cursor: "pointer",
+    marginBottom: -2,
+  });
+
+  if (loading) {
+    return (
+      <div style={containerStyle}>
+        <div style={{ height: 32, width: 100, background: "#e5e7eb", borderRadius: 6, marginBottom: 20 }} />
+        <div style={{ height: 28, width: "50%", background: "#e5e7eb", borderRadius: 6, marginBottom: 16 }} />
+        {[1, 2, 3].map((i) => (
+          <div key={i} style={{ height: 60, background: "#e5e7eb", borderRadius: 8, marginBottom: 8 }} />
+        ))}
+      </div>
+    );
+  }
+
+  if (error || !group) {
+    return (
+      <div style={containerStyle}>
+        <button onClick={() => navigate("/groups")} style={backButtonStyle}>
+          ← {t("groupDetail.back") ?? "Back"}
+        </button>
+        <div style={{ textAlign: "center", padding: "60px 20px" }}>
+          <div style={{ fontSize: 48, marginBottom: 16 }}>😕</div>
+          <p style={{ color: "#6b7280", fontSize: 16 }}>
+            {error ?? (t("groupDetail.notFound") ?? "Group not found")}
+          </p>
+        </div>
+      </div>
+    );
+  }
+
+  const isMember = group.members.some((m) => {
+    // Determine membership by matching progress data — user_id can come from members list
+    // We check if there's a progress entry with an "id" (indicates own data)
+    return progressEntries.some((e) => "id" in e);
+  });
+
+  return (
+    <div style={containerStyle}>
+      <button onClick={() => navigate("/groups")} style={backButtonStyle}>
+        ← {t("groupDetail.back") ?? "Back to Groups"}
+      </button>
+
+      {/* Header */}
+      <div style={{ marginBottom: 20 }}>
+        <h1 style={{ fontSize: isMobile ? 20 : 24, fontWeight: 700, color: "#1f2937", margin: "0 0 4px" }}>
+          {group.name}
+        </h1>
+        <p style={{ fontSize: 14, color: "#6b7280", margin: 0 }}>
+          {group.ebook_title} {group.ebook_author ? `— ${group.ebook_author}` : ""}
+        </p>
+      </div>
+
+      {/* Group actions */}
+      <div style={{ display: "flex", gap: 10, marginBottom: 20, flexWrap: "wrap" }}>
+        {!isMember ? (
+          <button
+            onClick={() => void handleJoin()}
+            style={{
+              padding: "10px 20px", borderRadius: 10, border: "none", background: "#4f46e5",
+              color: "#fff", fontSize: 14, fontWeight: 600, cursor: "pointer",
+            }}
+          >
+            {t("groupDetail.join") ?? "Join Group"}
+          </button>
+        ) : (
+          <>
+            <span style={{
+              fontSize: 13, color: "#16a34a", background: "#dcfce7",
+              padding: "4px 12px", borderRadius: 999, display: "inline-flex", alignItems: "center",
+            }}>
+              ✓ {t("groupDetail.member") ?? "Member"}
+            </span>
+            {group.created_by_email !== undefined /* can't check identity here, but leave is always available for non-creators */ && (
+              <button
+                onClick={() => void handleLeave()}
+                style={{
+                  padding: "10px 20px", borderRadius: 10, border: "1px solid #fca5a5",
+                  background: "#fff", color: "#b91c1c", fontSize: 14, cursor: "pointer",
+                }}
+              >
+                {t("groupDetail.leave") ?? "Leave Group"}
+              </button>
+            )}
+          </>
+        )}
+      </div>
+
+      {group.description && (
+        <p style={{ fontSize: 14, color: "#4b5563", marginBottom: 20, lineHeight: 1.6, background: "#fff", padding: isMobile ? 12 : 16, borderRadius: 10, border: "1px solid #e5e7eb" }}>
+          {group.description}
+        </p>
+      )}
+
+      {/* Tabs */}
+      <div style={tabBarStyle}>
+        <button style={tabStyle(tab === "progress")} onClick={() => setTab("progress")}>
+          {t("groupDetail.progressTab") ?? "Progress"}
+        </button>
+        {isAdmin && (
+          <button style={tabStyle(tab === "admin")} onClick={() => setTab("admin")}>
+            {t("groupDetail.adminTab") ?? "Admin Summary"}
+          </button>
+        )}
+      </div>
+
+      {/* Progress tab */}
+      {tab === "progress" && (
+        <div>
+          {progressEntries.length === 0 ? (
+            <div style={{ textAlign: "center", padding: "40px 20px", color: "#9ca3af" }}>
+              <p>{t("groupDetail.noProgress") ?? "No progress data yet."}</p>
+            </div>
+          ) : (
+            progressEntries.map((entry) => {
+              const isPrivate = "is_public" in entry && entry.is_public === false && "note" in entry;
+              const hasDetail = isDetail(entry);
+
+              return (
+                <div
+                  key={entry.user_id}
+                  style={{
+                    background: "#fff", borderRadius: 10, padding: isMobile ? 12 : 16,
+                    marginBottom: 10, border: "1px solid #e5e7eb",
+                    boxShadow: "0 1px 3px rgba(0,0,0,0.04)",
+                  }}
+                >
+                  <div style={{ display: "flex", justifyContent: "space-between", alignItems: "center", marginBottom: 6 }}>
+                    <span style={{ fontSize: 15, fontWeight: 600, color: "#1f2937" }}>
+                      {entry.user_email}
+                      {hasDetail && " (you)"}
+                    </span>
+                    {isPrivate ? (
+                      <span style={{ fontSize: 12, color: "#9ca3af", fontStyle: "italic" }}>
+                        🔒 {t("groupDetail.private") ?? "Private"}
+                      </span>
+                    ) : "section_label" in entry && (
+                      <span style={{ fontSize: 13, color: "#4f46e5", fontWeight: 500 }}>
+                        {entry.section_label}
+                      </span>
+                    )}
+                  </div>
+
+                  {!isPrivate && "percentage" in entry && (
+                    <div style={{ display: "flex", alignItems: "center", gap: 10 }}>
+                      <div style={{
+                        flex: 1, height: 8, borderRadius: 4, background: "#e5e7eb", overflow: "hidden",
+                      }}>
+                        <div style={{
+                          height: "100%",
+                          width: `${Math.min(100, entry.percentage)}%`,
+                          background: hasDetail ? "#4f46e5" : "#818cf8",
+                          borderRadius: 4,
+                          transition: "width 0.3s ease",
+                        }} />
+                      </div>
+                      <span style={{ fontSize: 13, fontWeight: 600, color: "#374151", whiteSpace: "nowrap" }}>
+                        {Math.round(entry.percentage)}%
+                      </span>
+                    </div>
+                  )}
+
+                  {hasDetail && entry.last_position && Object.keys(entry.last_position).length > 0 && (
+                    <div style={{ marginTop: 8, fontSize: 12, color: "#9ca3af" }}>
+                      {t("groupDetail.lastPosition") ?? "Last position"}: {JSON.stringify(entry.last_position)}
+                    </div>
+                  )}
+                </div>
+              );
+            })
+          )}
+        </div>
+      )}
+
+      {/* Admin tab */}
+      {tab === "admin" && adminSummary && (
+        <div>
+          <div style={{
+            display: "grid",
+            gridTemplateColumns: "repeat(auto-fit, minmax(140px, 1fr))",
+            gap: 12,
+            marginBottom: 24,
+          }}>
+            <StatCard
+              label={t("groupDetail.totalMembers") ?? "Members"}
+              value={String(adminSummary.total_members)}
+            />
+            <StatCard
+              label={t("groupDetail.started") ?? "Started"}
+              value={String(adminSummary.members_started)}
+            />
+            <StatCard
+              label={t("groupDetail.finished") ?? "Finished"}
+              value={String(adminSummary.members_finished)}
+            />
+            <StatCard
+              label={t("groupDetail.avgProgress") ?? "Avg Progress"}
+              value={`${Math.round(adminSummary.average_percentage)}%`}
+            />
+            <StatCard
+              label={t("groupDetail.avgTime") ?? "Avg Time"}
+              value={`${adminSummary.average_time_spent_hours}h`}
+            />
+          </div>
+
+          <h3 style={{ fontSize: 15, fontWeight: 600, color: "#1f2937", marginBottom: 12 }}>
+            {t("groupDetail.memberDetails") ?? "Member Details"}
+          </h3>
+          {adminSummary.member_details.map((m) => (
+            <div
+              key={m.user_id}
+              style={{
+                background: "#fff", borderRadius: 10, padding: isMobile ? 12 : 14,
+                marginBottom: 8, border: "1px solid #e5e7eb",
+                display: "flex", justifyContent: "space-between", alignItems: "center",
+              }}
+            >
+              <div>
+                <span style={{ fontSize: 14, fontWeight: 500, color: "#1f2937" }}>{m.user_email}</span>
+                <span style={{ fontSize: 12, color: "#9ca3af", marginLeft: 8 }}>
+                  {m.is_public ? "👁" : "🔒"}
+                </span>
+              </div>
+              <div style={{ display: "flex", gap: 16, fontSize: 13, color: "#6b7280" }}>
+                <span>Section {m.current_section}</span>
+                <span style={{ fontWeight: 600, color: "#4f46e5" }}>{Math.round(m.percentage)}%</span>
+                <span>⏱ {Math.round(m.time_spent_seconds / 60)}m</span>
+              </div>
+            </div>
+          ))}
+        </div>
+      )}
+    </div>
+  );
+}
+
+function StatCard({ label, value }: { label: string; value: string }) {
+  return (
+    <div style={{
+      background: "#fff", borderRadius: 10, padding: "14px 16px",
+      border: "1px solid #e5e7eb", textAlign: "center",
+    }}>
+      <div style={{ fontSize: 22, fontWeight: 700, color: "#4f46e5" }}>{value}</div>
+      <div style={{ fontSize: 12, color: "#6b7280", marginTop: 2 }}>{label}</div>
+    </div>
+  );
+}

frontend/src/pages/Library.tsx

@@ -242,6 +242,7 @@ export function LibraryPage() {
             <>
               <button onClick={() => navigate("/add")} style={{ ...TOUCH_TARGET, fontSize: 20, background: "none", border: "none", cursor: "pointer", padding: 8 }} title={t("library.addBook")}>➕</button>
               <button onClick={() => navigate("/bookmarks-notes")} style={{ ...TOUCH_TARGET, fontSize: 20, background: "none", border: "none", cursor: "pointer", padding: 8 }} title={t("library.bookmarks")}>🔖</button>
+              <button onClick={() => navigate("/groups")} style={{ ...TOUCH_TARGET, fontSize: 20, background: "none", border: "none", cursor: "pointer", padding: 8 }} title="Reading Groups">👥</button>
               <button onClick={() => navigate("/settings")} style={{ ...TOUCH_TARGET, fontSize: 20, background: "none", border: "none", cursor: "pointer", padding: 8 }} title={t("library.settings")}>⚙️</button>
               <button onClick={logout} style={{ ...TOUCH_TARGET, fontSize: 20, background: "none", border: "none", cursor: "pointer", padding: 8 }} title={t("library.logout")}>🚪</button>
             </>
@@ -249,6 +250,7 @@ export function LibraryPage() {
             <>
               <button onClick={() => navigate("/add")} className="btn">+ {t("library.addBook")}</button>
               <button onClick={() => navigate("/bookmarks-notes")} className="btn btn-secondary">{t("library.bookmarks")}</button>
+              <button onClick={() => navigate("/groups")} className="btn btn-secondary">👥 Reading Groups</button>
               <button onClick={() => navigate("/settings")} className="btn btn-secondary">{t("library.settings")}</button>
               <button onClick={logout} className="btn btn-danger">{t("library.logout")}</button>
             </>

frontend/src/pages/ReadingGroups.tsx

@@ -0,0 +1,288 @@
+import React, { useCallback, useEffect, useState } from "react";
+import { useNavigate } from "react-router-dom";
+import { useTranslation } from "react-i18n-lite";
+import { groupsApi } from "../api/groups";
+import { booksApi } from "../api/books";
+import type { ReadingGroupSummary } from "../types/groups";
+import type { EBookListItem } from "../types/book";
+import { useMediaQuery, BREAKPOINTS } from "../hooks/useMediaQuery";
+
+export function ReadingGroupsPage() {
+  const { t } = useTranslation();
+  const navigate = useNavigate();
+  const isMobile = useMediaQuery(BREAKPOINTS.md);
+
+  const [groups, setGroups] = useState<ReadingGroupSummary[]>([]);
+  const [ebooks, setEbooks] = useState<EBookListItem[]>([]);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState<string | null>(null);
+  const [showCreate, setShowCreate] = useState(false);
+  const [createName, setCreateName] = useState("");
+  const [createEbook, setCreateEbook] = useState<number | null>(null);
+  const [createDesc, setCreateDesc] = useState("");
+  const [creating, setCreating] = useState(false);
+
+  const loadGroups = useCallback(async () => {
+    try {
+      const data = await groupsApi.listGroups();
+      setGroups(data);
+      setError(null);
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to load groups");
+    } finally {
+      setLoading(false);
+    }
+  }, []);
+
+  const loadEbooks = useCallback(async () => {
+    try {
+      const data = await booksApi.getEBooks();
+      setEbooks(data);
+    } catch {
+      // Ebook list is optional; groups page still works without it
+    }
+  }, []);
+
+  useEffect(() => {
+    void loadGroups();
+    void loadEbooks();
+  }, [loadGroups, loadEbooks]);
+
+  const handleCreate = useCallback(async () => {
+    if (!createName.trim() || createEbook === null) return;
+    setCreating(true);
+    try {
+      await groupsApi.createGroup({
+        name: createName.trim(),
+        ebook: createEbook,
+        description: createDesc.trim(),
+      });
+      setShowCreate(false);
+      setCreateName("");
+      setCreateEbook(null);
+      setCreateDesc("");
+      void loadGroups();
+    } catch (err) {
+      setError(err instanceof Error ? err.message : "Failed to create group");
+    } finally {
+      setCreating(false);
+    }
+  }, [createName, createEbook, createDesc, loadGroups]);
+
+  const containerStyle: React.CSSProperties = {
+    maxWidth: 720,
+    margin: "0 auto",
+    padding: isMobile ? 16 : 24,
+    minHeight: "100vh",
+    background: "#f8f9fa",
+  };
+
+  const headerBar: React.CSSProperties = {
+    display: "flex",
+    justifyContent: "space-between",
+    alignItems: "center",
+    marginBottom: 24,
+  };
+
+  const cardStyle: React.CSSProperties = {
+    background: "#fff",
+    borderRadius: 12,
+    padding: isMobile ? 14 : 18,
+    marginBottom: 12,
+    cursor: "pointer",
+    boxShadow: "0 1px 4px rgba(0,0,0,0.06)",
+    border: "1px solid #e5e7eb",
+  };
+
+  if (loading) {
+    return (
+      <div style={containerStyle}>
+        <div style={{ height: 24, width: 200, background: "#e5e7eb", borderRadius: 6, marginBottom: 24 }} />
+        {[1, 2, 3].map((i) => (
+          <div key={i} style={{ ...cardStyle, cursor: "default" }}>
+            <div style={{ height: 20, width: "60%", background: "#e5e7eb", borderRadius: 4, marginBottom: 8 }} />
+            <div style={{ height: 14, width: "40%", background: "#e5e7eb", borderRadius: 4 }} />
+          </div>
+        ))}
+      </div>
+    );
+  }
+
+  return (
+    <div style={containerStyle}>
+      <div style={headerBar}>
+        <h1 style={{ fontSize: isMobile ? 20 : 24, fontWeight: 700, color: "#1f2937", margin: 0 }}>
+          📚 {t("readingGroups.title") ?? "Reading Groups"}
+        </h1>
+        <button
+          onClick={() => setShowCreate(true)}
+          style={{
+            padding: isMobile ? "10px 18px" : "8px 18px",
+            borderRadius: 10,
+            border: "none",
+            background: "#4f46e5",
+            color: "#fff",
+            fontSize: 14,
+            fontWeight: 600,
+            cursor: "pointer",
+            minHeight: 40,
+          }}
+        >
+          + {t("readingGroups.create") ?? "New Group"}
+        </button>
+      </div>
+
+      {error && (
+        <div style={{ padding: "12px 16px", background: "#fef2f2", borderRadius: 8, color: "#b91c1c", marginBottom: 16, fontSize: 14 }}>
+          {error}
+        </div>
+      )}
+
+      {/* Create modal */}
+      {showCreate && (
+        <div style={{
+          position: "fixed", inset: 0, background: "rgba(0,0,0,0.4)",
+          display: "flex", alignItems: "center", justifyContent: "center", zIndex: 100,
+        }}>
+          <div style={{
+            background: "#fff", borderRadius: 16, padding: 24, maxWidth: 420, width: "90%",
+            boxShadow: "0 10px 40px rgba(0,0,0,0.15)",
+          }}>
+            <h2 style={{ fontSize: 18, fontWeight: 700, marginBottom: 16, color: "#1f2937" }}>
+              {t("readingGroups.createTitle") ?? "Create Reading Group"}
+            </h2>
+
+            <label style={{ fontSize: 13, color: "#6b7280", display: "block", marginBottom: 4 }}>
+              {t("readingGroups.groupName") ?? "Group Name"}
+            </label>
+            <input
+              type="text"
+              value={createName}
+              onChange={(e) => setCreateName(e.target.value)}
+              placeholder={t("readingGroups.namePlaceholder") ?? "e.g., Book Club June"}
+              style={{
+                width: "100%", padding: "10px 14px", borderRadius: 8, border: "1px solid #d1d5db",
+                fontSize: 14, marginBottom: 14, boxSizing: "border-box",
+              }}
+            />
+
+            <label style={{ fontSize: 13, color: "#6b7280", display: "block", marginBottom: 4 }}>
+              {t("readingGroups.selectBook") ?? "Select Book"}
+            </label>
+            <select
+              value={createEbook ?? ""}
+              onChange={(e) => setCreateEbook(e.target.value ? Number(e.target.value) : null)}
+              style={{
+                width: "100%", padding: "10px 14px", borderRadius: 8, border: "1px solid #d1d5db",
+                fontSize: 14, marginBottom: 14, boxSizing: "border-box", background: "#fff",
+              }}
+            >
+              <option value="">-- {t("readingGroups.choose") ?? "Choose"} --</option>
+              {ebooks.map((eb) => (
+                <option key={eb.id} value={eb.id}>
+                  {eb.title} {eb.author ? `— ${eb.author}` : ""}
+                </option>
+              ))}
+            </select>
+
+            <label style={{ fontSize: 13, color: "#6b7280", display: "block", marginBottom: 4 }}>
+              {t("readingGroups.description") ?? "Description"} ({t("common.optional") ?? "optional"})
+            </label>
+            <textarea
+              value={createDesc}
+              onChange={(e) => setCreateDesc(e.target.value)}
+              rows={3}
+              style={{
+                width: "100%", padding: "10px 14px", borderRadius: 8, border: "1px solid #d1d5db",
+                fontSize: 14, marginBottom: 18, boxSizing: "border-box", resize: "vertical",
+              }}
+            />
+
+            <div style={{ display: "flex", gap: 10, justifyContent: "flex-end" }}>
+              <button
+                onClick={() => setShowCreate(false)}
+                style={{
+                  padding: "10px 20px", borderRadius: 8, border: "1px solid #d1d5db",
+                  background: "#fff", color: "#374151", fontSize: 14, cursor: "pointer",
+                }}
+              >
+                {t("common.cancel") ?? "Cancel"}
+              </button>
+              <button
+                onClick={() => void handleCreate()}
+                disabled={creating || !createName.trim() || createEbook === null}
+                style={{
+                  padding: "10px 20px", borderRadius: 8, border: "none",
+                  background: (!createName.trim() || createEbook === null) ? "#9ca3af" : "#4f46e5",
+                  color: "#fff", fontSize: 14, fontWeight: 600, cursor: (!createName.trim() || createEbook === null) ? "not-allowed" : "pointer",
+                }}
+              >
+                {creating ? (t("common.creating") ?? "Creating...") : (t("readingGroups.create") ?? "Create")}
+              </button>
+            </div>
+          </div>
+        </div>
+      )}
+
+      {/* Group list */}
+      {groups.length === 0 ? (
+        <div style={{ textAlign: "center", padding: "60px 20px", color: "#6b7280" }}>
+          <div style={{ fontSize: 48, marginBottom: 12 }}>📖</div>
+          <p style={{ fontSize: 16, marginBottom: 16 }}>
+            {t("readingGroups.empty") ?? "No reading groups yet. Create one to read together!"}
+          </p>
+        </div>
+      ) : (
+        groups.map((g) => (
+          <div
+            key={g.id}
+            style={cardStyle}
+            onClick={() => navigate(`/groups/${g.id}`)}
+          >
+            <div style={{ display: "flex", justifyContent: "space-between", alignItems: "flex-start" }}>
+              <div>
+                <h2 style={{ fontSize: isMobile ? 16 : 17, fontWeight: 600, color: "#1f2937", margin: "0 0 4px" }}>
+                  {g.name}
+                </h2>
+                <p style={{ fontSize: 13, color: "#6b7280", margin: "0 0 6px" }}>
+                  {g.ebook_title} {g.ebook_author ? `— ${g.ebook_author}` : ""}
+                </p>
+              </div>
+              <span style={{
+                fontSize: 12, color: "#4f46e5", background: "#eef2ff",
+                padding: "2px 10px", borderRadius: 999, whiteSpace: "nowrap",
+                minHeight: 24, display: "inline-flex", alignItems: "center",
+              }}>
+                {g.member_count} {g.member_count === 1
+                  ? (t("readingGroups.member") ?? "member")
+                  : (t("readingGroups.members") ?? "members")}
+              </span>
+            </div>
+
+            {g.my_progress && (
+              <div style={{ marginTop: 8, display: "flex", alignItems: "center", gap: 8 }}>
+                <div style={{
+                  flex: 1, height: 6, borderRadius: 3, background: "#e5e7eb", overflow: "hidden",
+                }}>
+                  <div style={{
+                    height: "100%", width: `${Math.min(100, g.my_progress.percentage)}%`,
+                    background: "#4f46e5", borderRadius: 3, transition: "width 0.3s ease",
+                  }} />
+                </div>
+                <span style={{ fontSize: 12, color: "#6b7280", whiteSpace: "nowrap" }}>
+                  {g.my_progress.section_label}
+                </span>
+              </div>
+            )}
+
+            {g.description && (
+              <p style={{ fontSize: 13, color: "#9ca3af", margin: "8px 0 0", lineHeight: 1.5 }}>
+                {g.description}
+              </p>
+            )}
+          </div>
+        ))
+      )}
+    </div>
+  );
+}

frontend/src/types/groups.ts

@@ -0,0 +1,104 @@
+/* ── Reading Groups ── */
+
+export interface MemberProgressPublic {
+  user_id: number;
+  user_email: string;
+  current_section: number;
+  total_sections: number;
+  section_label: string;
+  percentage: number;
+  time_spent_seconds: number;
+  updated_at: string;
+}
+
+export interface MemberProgressDetail {
+  id: number;
+  user_id: number;
+  user_email: string;
+  current_section: number;
+  total_sections: number;
+  section_label: string;
+  percentage: number;
+  time_spent_seconds: number;
+  last_position: Record<string, unknown>;
+  is_public: boolean;
+  updated_at: string;
+}
+
+export interface MemberProgressPrivateStub {
+  user_id: number;
+  user_email: string;
+  is_public: false;
+  note: string;
+}
+
+export type MemberProgressEntry =
+  | MemberProgressDetail
+  | MemberProgressPublic
+  | MemberProgressPrivateStub;
+
+export interface GroupMember {
+  id: number;
+  user_id: number;
+  user_email: string;
+  role: "member" | "admin";
+  joined_at: string;
+  progress: MemberProgressPublic | { is_public: false; note: string } | null;
+}
+
+export interface ReadingGroupSummary {
+  id: number;
+  name: string;
+  ebook: number;
+  ebook_title: string;
+  ebook_author: string;
+  created_by_email: string;
+  description: string;
+  member_count: number;
+  my_progress: {
+    current_section: number;
+    percentage: number;
+    time_spent_seconds: number;
+    section_label: string;
+  } | null;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface ReadingGroupDetail extends ReadingGroupSummary {
+  members: GroupMember[];
+}
+
+export interface CreateGroupPayload {
+  name: string;
+  ebook: number;
+  description?: string;
+}
+
+export interface UpdateProgressPayload {
+  current_section: number;
+  percentage?: number;
+  time_spent_delta?: number;
+  last_position?: Record<string, unknown>;
+  is_public?: boolean;
+}
+
+export interface AdminProgressSummary {
+  group_id: number;
+  group_name: string;
+  ebook_title: string;
+  total_members: number;
+  members_started: number;
+  members_finished: number;
+  average_percentage: number;
+  average_time_spent_hours: number;
+  member_details: {
+    user_id: number;
+    user_email: string;
+    current_section: number;
+    percentage: number;
+    time_spent_seconds: number;
+    is_public: boolean;
+    updated_at: string;
+  }[];
+}

mobile/.env.example

@@ -0,0 +1,10 @@
+# Mobile (Expo) environment (example – never commit real secrets)
+# Base URL of the Django backend. Must be reachable from the device/emulator.
+#   - Android emulator: http://10.0.2.2:8000
+#   - iOS simulator:    http://localhost:8000
+#   - Physical device:  http://<your-lan-ip>:8000
+EXPO_PUBLIC_API_URL=http://10.0.2.2:8000
+
+# EAS Build: set per profile in mobile/eas.json or via:
+#   eas secret:create --name EXPO_PUBLIC_API_URL --value https://your-api.example.com
+# Run all eas commands from mobile/ (not repo root).

mobile/App.tsx

@@ -1,4 +1,8 @@
 import React from "react";
+// Peer dependencies for @epubjs-react-native/core and gesture-handler.
+import "react-native-webview";
+import "react-native-reanimated";
+import { GestureHandlerRootView } from "react-native-gesture-handler";
 import { NavigationContainer } from "@react-navigation/native";
 import { StatusBar } from "expo-status-bar";
 import { AuthProvider } from "./src/context/AuthContext";
@@ -6,11 +10,13 @@ import { RootNavigator } from "./src/navigation/RootNavigator";
 
 export default function App() {
   return (
-    <AuthProvider>
+    <GestureHandlerRootView style={{ flex: 1 }}>
-      <NavigationContainer>
+      <AuthProvider>
-        <StatusBar style="auto" />
+        <NavigationContainer>
-        <RootNavigator />
+          <StatusBar style="auto" />
-      </NavigationContainer>
+          <RootNavigator />
-    </AuthProvider>
+        </NavigationContainer>
+      </AuthProvider>
+    </GestureHandlerRootView>
   );
-}
+}

mobile/app.json

@@ -21,7 +21,6 @@
       "package": "com.cloudreader.app"
     },
     "plugins": [
-      "expo-document-picker",
       "expo-file-system"
     ]
   }

mobile/eas.json

@@ -0,0 +1,42 @@
+{
+  "cli": {
+    "version": ">= 13.0.0",
+    "appVersionSource": "remote"
+  },
+  "build": {
+    "base": {
+      "node": "20.18.0",
+      "env": {
+        "EXPO_PUBLIC_API_URL": "https://api.example.com"
+      }
+    },
+    "development": {
+      "extends": "base",
+      "developmentClient": true,
+      "distribution": "internal",
+      "ios": {
+        "simulator": true
+      },
+      "android": {
+        "buildType": "apk"
+      },
+      "env": {
+        "EXPO_PUBLIC_API_URL": "http://10.0.2.2:8000"
+      }
+    },
+    "preview": {
+      "extends": "base",
+      "distribution": "internal",
+      "android": {
+        "buildType": "apk"
+      }
+    },
+    "production": {
+      "extends": "base",
+      "autoIncrement": true
+    }
+  },
+  "submit": {
+    "production": {}
+  }
+}

mobile/metro.config.js

@@ -0,0 +1,25 @@
+const { getDefaultConfig } = require("expo/metro-config");
+const path = require("path");
+
+const projectRoot = __dirname;
+const monorepoRoot = path.resolve(projectRoot, "..");
+
+/**
+ * Expo SDK 52+ configures Metro for Yarn/npm/pnpm workspaces automatically
+ * when using expo/metro-config. This file keeps an explicit monorepo root so
+ * @cloud-reader/shared (packages/shared) resolves reliably in dev and on EAS.
+ *
+ * If you previously added manual watchFolders/nodeModulesPaths and things
+ * work, prefer this minimal config. After changes: npx expo start --clear
+ *
+ * @see https://docs.expo.dev/guides/monorepos/
+ */
+const config = getDefaultConfig(projectRoot);
+
+config.watchFolders = [monorepoRoot];
+config.resolver.nodeModulesPaths = [
+  path.resolve(projectRoot, "node_modules"),
+  path.resolve(monorepoRoot, "node_modules"),
+];
+
+module.exports = config;

mobile/package.json

@@ -8,7 +8,11 @@
     "android": "expo start --android",
     "ios": "expo start --ios",
     "web": "expo start --web",
-    "lint": "eslint ."
+    "lint": "eslint .",
+    "eas:init": "eas init",
+    "eas:build:dev": "eas build --profile development --platform all",
+    "eas:build:preview": "eas build --profile preview --platform all",
+    "eas:build:prod": "eas build --profile production --platform all"
   },
   "dependencies": {
     "expo": "~52.0.0",
@@ -22,10 +26,12 @@
     "@react-navigation/bottom-tabs": "^7.0.0",
     "axios": "^1.7.9",
     "@react-native-async-storage/async-storage": "2.1.0",
-    "expo-document-picker": "~13.0.0",
+    "@epubjs-react-native/core": "1.4.7",
+    "@epubjs-react-native/expo-file-system": "1.1.4",
     "expo-file-system": "~18.0.0",
     "react-native-gesture-handler": "~2.20.0",
     "react-native-reanimated": "~3.16.0",
+    "react-native-webview": "13.12.5",
     "@cloud-reader/shared": "*"
   },
   "devDependencies": {

mobile/src/api/annotations.ts

@@ -1,55 +1,31 @@
 import api from "./client";
-import type {
+import type { PaginatedResponse } from "@cloud-reader/shared";
-  Bookmark,
+import type { Bookmark, CreateMarkerPayload } from "../types";
-  Note,
-  CreateBookmarkPayload,
-  CreateNotePayload,
-  PaginatedResponse,
-} from "@cloud-reader/shared";
 
-export function fetchBookmarks(
+export async function fetchBookmarks(
-  bookId?: string,
+  ebookId?: string | number,
 ): Promise<PaginatedResponse<Bookmark>> {
-  const params = bookId ? { book: bookId } : {};
+  const params: Record<string, string> = {};
-  return api
+  if (ebookId != null && ebookId !== "") {
-    .get<PaginatedResponse<Bookmark>>("/api/annotations/bookmarks/", { params })
+    params.ebook = String(ebookId);
-    .then((res) => res.data);
+  }
+  const { data } = await api.get<PaginatedResponse<Bookmark>>(
+    "/api/annotations/bookmarks/",
+    { params },
+  );
+  return data;
 }
 
-export function createBookmark(
+export async function createMarker(
-  payload: CreateBookmarkPayload,
+  payload: CreateMarkerPayload,
 ): Promise<Bookmark> {
-  return api
+  const { data } = await api.post<Bookmark>(
-    .post<Bookmark>("/api/annotations/bookmarks/", payload)
+    "/api/annotations/bookmarks/",
-    .then((res) => res.data);
+    payload,
+  );
+  return data;
 }
 
-export function deleteBookmark(id: string): Promise<void> {
+export async function deleteBookmark(id: string): Promise<void> {
-  return api.delete(`/api/annotations/bookmarks/${id}/`).then(() => {});
+  await api.delete(`/api/annotations/bookmarks/${id}/`);
 }
-
-export function fetchNotes(bookId?: string): Promise<PaginatedResponse<Note>> {
-  const params = bookId ? { book: bookId } : {};
-  return api
-    .get<PaginatedResponse<Note>>("/api/annotations/notes/", { params })
-    .then((res) => res.data);
-}
-
-export function createNote(payload: CreateNotePayload): Promise<Note> {
-  return api
-    .post<Note>("/api/annotations/notes/", payload)
-    .then((res) => res.data);
-}
-
-export function updateNote(
-  id: string,
-  content: string,
-): Promise<Note> {
-  return api
-    .patch<Note>(`/api/annotations/notes/${id}/`, { content })
-    .then((res) => res.data);
-}
-
-export function deleteNote(id: string): Promise<void> {
-  return api.delete(`/api/annotations/notes/${id}/`).then(() => {});
-}

mobile/src/api/books.ts

@@ -1,31 +1,12 @@
 import api from "./client";
 import type { Book, PaginatedResponse } from "@cloud-reader/shared";
 
-export function fetchBooks(
-  page = 1,
-  pageSize = 20,
-): Promise<PaginatedResponse<Book>> {
-  return api
-    .get<PaginatedResponse<Book>>("/api/books/", {
-      params: { page, page_size: pageSize },
-    })
-    .then((res) => res.data);
-}
-
-export function fetchBook(id: string): Promise<Book> {
-  return api.get<Book>(`/api/books/${id}/`).then((res) => res.data);
-}
-
 export function searchBooks(
   query: string,
 ): Promise<PaginatedResponse<Book>> {
   return api
-    .get<PaginatedResponse<Book>>("/api/books/search/", {
+    .get<PaginatedResponse<Book>>("/api/books/", {
       params: { q: query },
     })
     .then((res) => res.data);
 }
-
-export function deleteBook(id: string): Promise<void> {
-  return api.delete(`/api/books/${id}/`).then(() => {});
-}

mobile/src/api/client.ts

@@ -1,5 +1,6 @@
 import axios, { type AxiosError, type InternalAxiosRequestConfig } from "axios";
 import AsyncStorage from "@react-native-async-storage/async-storage";
+import type { TokenResponse } from "@cloud-reader/shared";
 
 const STORAGE_KEYS = {
   ACCESS_TOKEN: "access_token",
@@ -39,6 +40,26 @@ async function clearTokens(): Promise<void> {
   ]);
 }
 
+async function saveTokens(tokens: TokenResponse): Promise<void> {
+  await setTokens(tokens.access, tokens.refresh);
+}
+
+async function loadTokens(): Promise<TokenResponse | null> {
+  const [access, refresh] = await Promise.all([
+    getAccessToken(),
+    getRefreshToken(),
+  ]);
+  if (!access || !refresh) {
+    return null;
+  }
+  return { access, refresh };
+}
+
+/** Absolute base URL used for direct (non-axios) requests like file downloads. */
+function getApiBaseUrl(): string {
+  return api.defaults.baseURL ?? "";
+}
+
 // ── Request interceptor ─────────────────────────────────────────────
 
 api.interceptors.request.use(async (config: InternalAxiosRequestConfig) => {
@@ -136,5 +157,14 @@ api.interceptors.response.use(
   },
 );
 
-export { getAccessToken, getRefreshToken, setTokens, clearTokens };
+const apiClient = api;
+
+export {
+  apiClient,
+  getAccessToken,
+  saveTokens,
+  loadTokens,
+  clearTokens,
+  getApiBaseUrl,
+};
 export default api;

mobile/src/api/ebooks.ts

@@ -1,54 +1,35 @@
-import { apiClient } from "./client";
+import { apiClient, getApiBaseUrl } from "./client";
 import type {
   EBookListItem,
   EBookDetail,
-  ReadingProgress,
-  ReadingSettings,
   TocResponse,
-  ContentResponse,
   PaginatedResponse,
 } from "@cloud-reader/shared";
 
 export const ebooksApi = {
-  /** List uploaded e-books */
+  /** List the authenticated user's uploaded e-books */
   list() {
-    return apiClient.get<PaginatedResponse<EBookListItem>>("/api/ebooks/");
+    return apiClient.get<PaginatedResponse<EBookListItem>>(
+      "/api/books/ebooks/",
+    );
   },
 
-  /** Get e-book detail */
+  /** Get e-book detail (metadata, format, progress) */
   get(id: number) {
-    return apiClient.get<EBookDetail>(`/api/ebooks/${id}/`);
+    return apiClient.get<EBookDetail>(`/api/books/ebooks/${id}/`);
   },
 
-  /** Get table of contents */
+  /** Get the table of contents (used as a fallback for chapter navigation) */
   getToc(id: number) {
-    return apiClient.get<TocResponse>(`/api/ebooks/${id}/toc/`);
+    return apiClient.get<TocResponse>(`/api/books/ebooks/${id}/toc/`);
   },
 
-  /** Get page content */
+  /**
-  getContent(id: number, page: number) {
+   * Absolute URL to stream the raw ebook file. The endpoint requires JWT auth,
-    return apiClient.get<ContentResponse>(
+   * so callers download it with an Authorization header (e.g. via
-      `/api/ebooks/${id}/content/?page=${page}`,
+   * expo-file-system) rather than handing the URL to a renderer directly.
-    );
+   */
+  getFileUrl(id: number): string {
+    return `${getApiBaseUrl()}/api/books/ebooks/${id}/file/`;
   },
-
+};
-  /** Update reading progress */
-  updateProgress(id: number, data: Partial<ReadingProgress>) {
-    return apiClient.patch<ReadingProgress>(
-      `/api/ebooks/${id}/progress/`,
-      data,
-    );
-  },
-
-  /** Get or update reading settings */
-  getSettings(id: number) {
-    return apiClient.get<ReadingSettings>(`/api/ebooks/${id}/settings/`);
-  },
-
-  updateSettings(id: number, data: Partial<ReadingSettings>) {
-    return apiClient.patch<ReadingSettings>(
-      `/api/ebooks/${id}/settings/`,
-      data,
-    );
-  },
-};

mobile/src/api/index.ts

@@ -1,4 +0,0 @@
-export { apiClient, saveTokens, loadTokens, clearTokens } from "./client";
-export { booksApi } from "./books";
-export { ebooksApi } from "./ebooks";
-export { annotationsApi } from "./annotations";

mobile/src/api/reader.ts

@@ -0,0 +1,75 @@
+/**
+ * Reader API client — reading settings and per-book progress.
+ * Mirrors frontend/src/api/reader.ts. Uses the shared axios client so the
+ * JWT access token is attached automatically.
+ */
+
+import api from "./client";
+import type { ReadingProgress, ReadingSettings } from "../types/reader";
+
+export async function getReadingSettings(): Promise<ReadingSettings> {
+  const { data } = await api.get<ReadingSettings>("/api/reader/settings/");
+  return data;
+}
+
+export async function updateReadingSettings(
+  settings: Partial<ReadingSettings>,
+): Promise<ReadingSettings> {
+  const { data } = await api.patch<ReadingSettings>(
+    "/api/reader/settings/",
+    settings,
+  );
+  return data;
+}
+
+interface ProgressWire {
+  current_position: number;
+  last_page: number;
+  epub_location?: string;
+  updated_at?: string;
+}
+
+function toReadingProgress(bookId: number, data: ProgressWire): ReadingProgress {
+  return {
+    id: bookId,
+    book: bookId,
+    current_chapter: data.last_page || 1,
+    current_position: data.current_position ?? 0,
+    percentage: data.current_position ?? 0,
+    epub_location: data.epub_location ?? "",
+    updated_at: data.updated_at ?? "",
+  };
+}
+
+export async function getReadingProgress(
+  bookId: number,
+): Promise<ReadingProgress> {
+  const { data } = await api.get<ProgressWire>(
+    `/api/books/ebooks/${bookId}/progress/`,
+  );
+  return toReadingProgress(bookId, data);
+}
+
+export async function updateReadingProgress(
+  bookId: number,
+  progress: Partial<ReadingProgress>,
+): Promise<ReadingProgress> {
+  const body: Record<string, string | number> = {};
+  if (
+    progress.percentage !== undefined ||
+    progress.current_position !== undefined
+  ) {
+    body.current_position = progress.percentage ?? progress.current_position ?? 0;
+  }
+  if (progress.current_chapter !== undefined) {
+    body.last_page = progress.current_chapter;
+  }
+  if (progress.epub_location !== undefined) {
+    body.epub_location = progress.epub_location;
+  }
+  const { data } = await api.patch<ProgressWire>(
+    `/api/books/ebooks/${bookId}/progress/`,
+    body,
+  );
+  return toReadingProgress(bookId, data);
+}

mobile/src/components/reader/BookmarksModal.tsx

@@ -0,0 +1,147 @@
+import { type ReactNode } from "react";
+import {
+  Text,
+  FlatList,
+  TouchableOpacity,
+  StyleSheet,
+  View,
+} from "react-native";
+import { resolvePalette } from "../../utils/epubTheme";
+import type { ReadingSettings } from "../../types/reader";
+import type { Bookmark } from "../../types";
+import { ReaderBottomSheet } from "./ReaderBottomSheet";
+
+interface BookmarksModalProps {
+  visible: boolean;
+  bookmarks: Bookmark[];
+  settings: ReadingSettings;
+  onSelect: (bookmark: Bookmark) => void;
+  onDelete: (bookmark: Bookmark) => void;
+  onClose: () => void;
+}
+
+export function BookmarksModal({
+  visible,
+  bookmarks,
+  settings,
+  onSelect,
+  onDelete,
+  onClose,
+}: BookmarksModalProps): ReactNode {
+  const palette = resolvePalette(settings);
+
+  return (
+    <ReaderBottomSheet
+      visible={visible}
+      title="Bookmarks & highlights"
+      chromeColor={palette.chrome}
+      textColor={palette.text}
+      onClose={onClose}
+    >
+      <FlatList
+        data={bookmarks}
+        keyExtractor={(item) => item.id}
+        ListEmptyComponent={
+          <Text style={[styles.empty, { color: palette.text }]}>
+            No bookmarks yet. Tap the star to bookmark a page, or select text to
+            highlight it.
+          </Text>
+        }
+        renderItem={({ item }) => (
+          <View style={styles.row}>
+            <TouchableOpacity
+              style={styles.rowMain}
+              onPress={() => onSelect(item)}
+            >
+              {item.highlight_color ? (
+                <View
+                  style={[
+                    styles.dot,
+                    { backgroundColor: item.highlight_color },
+                  ]}
+                />
+              ) : (
+                <Text style={styles.star}>★</Text>
+              )}
+              <View style={styles.rowTextWrap}>
+                {item.chapter_title ? (
+                  <Text
+                    style={[styles.chapter, { color: palette.text }]}
+                    numberOfLines={1}
+                  >
+                    {item.chapter_title}
+                  </Text>
+                ) : null}
+                <Text
+                  style={[styles.excerpt, { color: palette.text }]}
+                  numberOfLines={2}
+                >
+                  {item.content || item.location_text || "Bookmarked page"}
+                </Text>
+              </View>
+            </TouchableOpacity>
+            <TouchableOpacity
+              onPress={() => onDelete(item)}
+              hitSlop={8}
+              style={styles.deleteButton}
+            >
+              <Text style={styles.deleteText}>Delete</Text>
+            </TouchableOpacity>
+          </View>
+        )}
+      />
+    </ReaderBottomSheet>
+  );
+}
+
+const styles = StyleSheet.create({
+  row: {
+    flexDirection: "row",
+    alignItems: "center",
+    paddingVertical: 12,
+    paddingHorizontal: 16,
+    borderTopWidth: StyleSheet.hairlineWidth,
+    borderTopColor: "rgba(127,127,127,0.2)",
+  },
+  rowMain: {
+    flex: 1,
+    flexDirection: "row",
+    alignItems: "center",
+  },
+  rowTextWrap: {
+    flex: 1,
+    marginLeft: 10,
+  },
+  star: {
+    fontSize: 16,
+    color: "#4f8ef7",
+  },
+  dot: {
+    width: 14,
+    height: 14,
+    borderRadius: 7,
+  },
+  chapter: {
+    fontSize: 12,
+    opacity: 0.7,
+    marginBottom: 2,
+  },
+  excerpt: {
+    fontSize: 14,
+  },
+  deleteButton: {
+    marginLeft: 12,
+    paddingHorizontal: 10,
+    paddingVertical: 6,
+  },
+  deleteText: {
+    color: "#ff453a",
+    fontSize: 13,
+    fontWeight: "600",
+  },
+  empty: {
+    padding: 24,
+    textAlign: "center",
+    opacity: 0.7,
+  },
+});

mobile/src/components/reader/EpubReaderView.tsx

@@ -0,0 +1,436 @@
+import { useCallback, useEffect, useRef, useState, type ReactNode } from "react";
+import {
+  View,
+  Text,
+  ActivityIndicator,
+  StyleSheet,
+  type LayoutChangeEvent,
+} from "react-native";
+import { SafeAreaView } from "react-native-safe-area-context";
+import { Reader, ReaderProvider, useReader } from "@epubjs-react-native/core";
+import { useFileSystem } from "@epubjs-react-native/expo-file-system";
+import * as FileSystem from "expo-file-system";
+import type { EBookDetail } from "@cloud-reader/shared";
+import { getAccessToken } from "../../api/client";
+import { ebooksApi } from "../../api/ebooks";
+import { getReadingProgress, updateReadingProgress } from "../../api/reader";
+import {
+  fetchBookmarks,
+  createMarker,
+  deleteBookmark,
+} from "../../api/annotations";
+import { useReadingSettings } from "../../hooks/useReadingSettings";
+import {
+  buildEpubTheme,
+  FONT_STACKS,
+  resolvePalette,
+} from "../../utils/epubTheme";
+import type { Bookmark } from "../../types";
+import { ReaderToolbar } from "./ReaderToolbar";
+import { TocModal, type TocItem } from "./TocModal";
+import { ReadingSettingsModal } from "./ReadingSettingsModal";
+import { BookmarksModal } from "./BookmarksModal";
+
+const HIGHLIGHT_COLOR = "#ffd54a";
+const PROGRESS_SAVE_MS = 800;
+
+/** Loose view of the epubjs-react-native reader API we rely on. */
+interface ReaderApi {
+  goToLocation?: (target: string) => void;
+  changeTheme?: (theme: Record<string, Record<string, string>>) => void;
+  changeFontSize?: (size: string) => void;
+  changeFontFamily?: (font: string) => void;
+  addAnnotation?: (
+    type: string,
+    cfiRange: string,
+    data?: unknown,
+    styles?: Record<string, unknown>,
+  ) => void;
+  removeAnnotationByCfi?: (cfi: string) => void;
+  removeSelection?: () => void;
+  toc?: TocItem[];
+}
+
+interface EpubLocation {
+  start?: { cfi?: string };
+}
+
+interface EpubSection {
+  label?: string;
+  index?: number;
+}
+
+interface EpubReaderViewProps {
+  book: EBookDetail;
+  ebookId: number;
+  onClose: () => void;
+}
+
+export function EpubReaderView(props: EpubReaderViewProps): ReactNode {
+  return (
+    <ReaderProvider>
+      <EpubReaderInner {...props} />
+    </ReaderProvider>
+  );
+}
+
+function EpubReaderInner({
+  book,
+  ebookId,
+  onClose,
+}: EpubReaderViewProps): ReactNode {
+  const reader = useReader() as unknown as ReaderApi;
+  const { settings, updateSettings } = useReadingSettings();
+
+  const [src, setSrc] = useState<string | null>(null);
+  const [initialLocation, setInitialLocation] = useState<string | undefined>();
+  const [fileError, setFileError] = useState(false);
+  const [ready, setReady] = useState(false);
+  const [size, setSize] = useState<{ width: number; height: number } | null>(
+    null,
+  );
+
+  const [progressPct, setProgressPct] = useState(
+    Math.round(book.progress?.current_position ?? 0),
+  );
+  const [chapterTitle, setChapterTitle] = useState("");
+  const [currentCfi, setCurrentCfi] = useState("");
+  const [bookmarks, setBookmarks] = useState<Bookmark[]>([]);
+
+  const [tocOpen, setTocOpen] = useState(false);
+  const [settingsOpen, setSettingsOpen] = useState(false);
+  const [bookmarksOpen, setBookmarksOpen] = useState(false);
+
+  const currentCfiRef = useRef("");
+  const progressPctRef = useRef(progressPct);
+  const sectionRef = useRef<{ index: number; label: string }>({
+    index: 0,
+    label: "",
+  });
+  const bookmarksRef = useRef<Bookmark[]>([]);
+  const saveTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
+
+  useEffect(() => {
+    bookmarksRef.current = bookmarks;
+  }, [bookmarks]);
+
+  // Download the EPUB with auth, and resolve the saved resume location.
+  useEffect(() => {
+    let active = true;
+    (async () => {
+      try {
+        const progress = await getReadingProgress(ebookId).catch(() => null);
+        if (active && progress?.epub_location) {
+          setInitialLocation(progress.epub_location);
+          currentCfiRef.current = progress.epub_location;
+          setCurrentCfi(progress.epub_location);
+        }
+        const token = await getAccessToken();
+        const url = ebooksApi.getFileUrl(ebookId);
+        const dest = `${FileSystem.cacheDirectory}ebook-${ebookId}.epub`;
+        const result = await FileSystem.downloadAsync(url, dest, {
+          headers: token ? { Authorization: `Bearer ${token}` } : undefined,
+        });
+        if (!active) return;
+        if (result.status >= 400) {
+          setFileError(true);
+          return;
+        }
+        setSrc(result.uri);
+      } catch {
+        if (active) setFileError(true);
+      }
+    })();
+    return () => {
+      active = false;
+    };
+  }, [ebookId]);
+
+  // Load existing bookmarks/highlights for this book.
+  useEffect(() => {
+    let active = true;
+    fetchBookmarks(ebookId)
+      .then((res) => {
+        if (active) setBookmarks(res.results);
+      })
+      .catch(() => {
+        /* bookmarks are optional */
+      });
+    return () => {
+      active = false;
+    };
+  }, [ebookId]);
+
+  // Apply typography/theme to the rendition once it is ready and on changes.
+  useEffect(() => {
+    if (!ready) return;
+    try {
+      reader.changeTheme?.(buildEpubTheme(settings));
+      reader.changeFontSize?.(`${settings.font_size}px`);
+      reader.changeFontFamily?.(FONT_STACKS[settings.font_family]);
+    } catch {
+      /* ignore rendition styling errors */
+    }
+  }, [ready, settings, reader]);
+
+  const flushProgress = useCallback(() => {
+    const cfi = currentCfiRef.current;
+    if (!cfi) return;
+    updateReadingProgress(ebookId, {
+      percentage: progressPctRef.current,
+      epub_location: cfi,
+      current_chapter: sectionRef.current.index + 1,
+    }).catch(() => {
+      /* progress is best-effort */
+    });
+  }, [ebookId]);
+
+  // Flush the latest progress when leaving the reader.
+  useEffect(
+    () => () => {
+      if (saveTimerRef.current) clearTimeout(saveTimerRef.current);
+      flushProgress();
+    },
+    [flushProgress],
+  );
+
+  const handleReady = useCallback(() => {
+    setReady(true);
+    bookmarksRef.current.forEach((bookmark) => {
+      if (bookmark.highlight_color && bookmark.epub_cfi) {
+        try {
+          reader.addAnnotation?.("highlight", bookmark.epub_cfi, undefined, {
+            fill: bookmark.highlight_color,
+          });
+        } catch {
+          /* highlight rendering is best-effort */
+        }
+      }
+    });
+  }, [reader]);
+
+  const handleLocationChange = useCallback(
+    (
+      _total: number,
+      location: EpubLocation,
+      progress: number,
+      section: EpubSection | null,
+    ) => {
+      const cfi = location?.start?.cfi ?? "";
+      if (cfi) {
+        currentCfiRef.current = cfi;
+        setCurrentCfi(cfi);
+      }
+      const pct = Math.round(progress ?? 0);
+      progressPctRef.current = pct;
+      setProgressPct(pct);
+      const label = section?.label?.trim() ?? "";
+      sectionRef.current = {
+        index: section?.index ?? sectionRef.current.index,
+        label,
+      };
+      setChapterTitle(label);
+
+      if (saveTimerRef.current) clearTimeout(saveTimerRef.current);
+      saveTimerRef.current = setTimeout(flushProgress, PROGRESS_SAVE_MS);
+    },
+    [flushProgress],
+  );
+
+  const handleSelected = useCallback(
+    async (selectedText: string, cfiRange: string) => {
+      const excerpt = (selectedText ?? "").slice(0, 280);
+      try {
+        const created = await createMarker({
+          ebook: ebookId,
+          epub_cfi: cfiRange,
+          chapter_index: sectionRef.current.index,
+          chapter_title: sectionRef.current.label,
+          location_text: excerpt,
+          content: excerpt,
+          highlight_color: HIGHLIGHT_COLOR,
+        });
+        setBookmarks((prev) => [created, ...prev]);
+        try {
+          reader.addAnnotation?.("highlight", cfiRange, undefined, {
+            fill: HIGHLIGHT_COLOR,
+          });
+          reader.removeSelection?.();
+        } catch {
+          /* annotation rendering is best-effort */
+        }
+      } catch {
+        /* ignore highlight save failures */
+      }
+    },
+    [ebookId, reader],
+  );
+
+  const handleToggleBookmarkHere = useCallback(async () => {
+    const cfi = currentCfiRef.current;
+    if (!cfi) return;
+    const existing = bookmarksRef.current.find((b) => b.epub_cfi === cfi);
+    if (existing) {
+      setBookmarks((prev) => prev.filter((b) => b.id !== existing.id));
+      try {
+        reader.removeAnnotationByCfi?.(cfi);
+      } catch {
+        /* best-effort */
+      }
+      deleteBookmark(existing.id).catch(() => {});
+      return;
+    }
+    try {
+      const created = await createMarker({
+        ebook: ebookId,
+        epub_cfi: cfi,
+        chapter_index: sectionRef.current.index,
+        chapter_title: sectionRef.current.label,
+        location_text: sectionRef.current.label,
+      });
+      setBookmarks((prev) => [created, ...prev]);
+    } catch {
+      /* ignore bookmark save failures */
+    }
+  }, [ebookId, reader]);
+
+  const handleSelectBookmark = useCallback(
+    (bookmark: Bookmark) => {
+      setBookmarksOpen(false);
+      try {
+        reader.goToLocation?.(bookmark.epub_cfi);
+      } catch {
+        /* best-effort */
+      }
+    },
+    [reader],
+  );
+
+  const handleDeleteBookmark = useCallback(
+    (bookmark: Bookmark) => {
+      setBookmarks((prev) => prev.filter((b) => b.id !== bookmark.id));
+      try {
+        if (bookmark.highlight_color) {
+          reader.removeAnnotationByCfi?.(bookmark.epub_cfi);
+        }
+      } catch {
+        /* best-effort */
+      }
+      deleteBookmark(bookmark.id).catch(() => {});
+    },
+    [reader],
+  );
+
+  const handleTocSelect = useCallback(
+    (href: string) => {
+      setTocOpen(false);
+      try {
+        reader.goToLocation?.(href);
+      } catch {
+        /* best-effort */
+      }
+    },
+    [reader],
+  );
+
+  const onReaderLayout = useCallback((event: LayoutChangeEvent) => {
+    const { width, height } = event.nativeEvent.layout;
+    setSize((prev) =>
+      prev && prev.width === width && prev.height === height
+        ? prev
+        : { width, height },
+    );
+  }, []);
+
+  const palette = resolvePalette(settings);
+  const isBookmarked = bookmarks.some((b) => b.epub_cfi === currentCfi);
+
+  return (
+    <SafeAreaView
+      style={[styles.container, { backgroundColor: palette.background }]}
+      edges={["top", "bottom"]}
+    >
+      <ReaderToolbar
+        title={book.title}
+        chapterTitle={chapterTitle}
+        progressPct={progressPct}
+        settings={settings}
+        isBookmarked={isBookmarked}
+        onBack={onClose}
+        onToggleToc={() => setTocOpen(true)}
+        onToggleSettings={() => setSettingsOpen(true)}
+        onToggleBookmarks={() => setBookmarksOpen(true)}
+        onToggleBookmarkHere={handleToggleBookmarkHere}
+      />
+
+      <View style={styles.readerArea} onLayout={onReaderLayout}>
+        {fileError ? (
+          <View style={styles.centered}>
+            <Text style={[styles.message, { color: palette.text }]}>
+              Could not download this book. Check your connection and try again.
+            </Text>
+          </View>
+        ) : src && size ? (
+          <Reader
+            src={src}
+            fileSystem={useFileSystem}
+            width={size.width}
+            height={size.height}
+            initialLocation={initialLocation}
+            enableSelection
+            flow="paginated"
+            defaultTheme={buildEpubTheme(settings)}
+            onReady={handleReady}
+            onLocationChange={handleLocationChange}
+            onSelected={handleSelected}
+          />
+        ) : (
+          <View style={styles.centered}>
+            <ActivityIndicator size="large" color="#4f8ef7" />
+          </View>
+        )}
+      </View>
+
+      <TocModal
+        visible={tocOpen}
+        toc={reader.toc ?? []}
+        settings={settings}
+        onSelect={handleTocSelect}
+        onClose={() => setTocOpen(false)}
+      />
+      <ReadingSettingsModal
+        visible={settingsOpen}
+        settings={settings}
+        onChange={updateSettings}
+        onClose={() => setSettingsOpen(false)}
+      />
+      <BookmarksModal
+        visible={bookmarksOpen}
+        bookmarks={bookmarks}
+        settings={settings}
+        onSelect={handleSelectBookmark}
+        onDelete={handleDeleteBookmark}
+        onClose={() => setBookmarksOpen(false)}
+      />
+    </SafeAreaView>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: {
+    flex: 1,
+  },
+  readerArea: {
+    flex: 1,
+  },
+  centered: {
+    flex: 1,
+    justifyContent: "center",
+    alignItems: "center",
+    padding: 24,
+  },
+  message: {
+    fontSize: 15,
+    textAlign: "center",
+  },
+});

mobile/src/components/reader/ReaderBottomSheet.tsx

@@ -0,0 +1,92 @@
+import { type ReactNode } from "react";
+import {
+  Modal,
+  View,
+  Text,
+  TouchableOpacity,
+  StyleSheet,
+  type StyleProp,
+  type ViewStyle,
+} from "react-native";
+
+interface ReaderBottomSheetProps {
+  visible: boolean;
+  title: string;
+  chromeColor: string;
+  textColor: string;
+  onClose: () => void;
+  children: ReactNode;
+  /** When true, caps sheet height (TOC/bookmarks). Settings uses a full-width panel. */
+  tall?: boolean;
+  sheetStyle?: StyleProp<ViewStyle>;
+}
+
+export function ReaderBottomSheet({
+  visible,
+  title,
+  chromeColor,
+  textColor,
+  onClose,
+  children,
+  tall = true,
+  sheetStyle,
+}: ReaderBottomSheetProps): ReactNode {
+  return (
+    <Modal
+      visible={visible}
+      animationType="slide"
+      transparent
+      onRequestClose={onClose}
+    >
+      <View style={styles.backdrop}>
+        <View
+          style={[
+            styles.sheet,
+            tall && styles.sheetTall,
+            { backgroundColor: chromeColor },
+            sheetStyle,
+          ]}
+        >
+          <View style={styles.header}>
+            <Text style={[styles.headerTitle, { color: textColor }]}>
+              {title}
+            </Text>
+            <TouchableOpacity onPress={onClose} hitSlop={12}>
+              <Text style={[styles.close, { color: textColor }]}>✕</Text>
+            </TouchableOpacity>
+          </View>
+          {children}
+        </View>
+      </View>
+    </Modal>
+  );
+}
+
+const styles = StyleSheet.create({
+  backdrop: {
+    flex: 1,
+    backgroundColor: "rgba(0,0,0,0.4)",
+    justifyContent: "flex-end",
+  },
+  sheet: {
+    borderTopLeftRadius: 16,
+    borderTopRightRadius: 16,
+    paddingBottom: 24,
+  },
+  sheetTall: {
+    maxHeight: "75%",
+  },
+  header: {
+    flexDirection: "row",
+    alignItems: "center",
+    justifyContent: "space-between",
+    padding: 16,
+  },
+  headerTitle: {
+    fontSize: 16,
+    fontWeight: "700",
+  },
+  close: {
+    fontSize: 18,
+  },
+});

mobile/src/components/reader/ReaderToolbar.tsx

@@ -0,0 +1,152 @@
+import { type ReactNode } from "react";
+import { View, Text, TouchableOpacity, StyleSheet } from "react-native";
+import { resolvePalette } from "../../utils/epubTheme";
+import type { ReadingSettings } from "../../types/reader";
+
+interface ReaderToolbarProps {
+  title: string;
+  chapterTitle: string;
+  progressPct: number;
+  settings: ReadingSettings;
+  isBookmarked: boolean;
+  onBack: () => void;
+  onToggleToc: () => void;
+  onToggleSettings: () => void;
+  onToggleBookmarks: () => void;
+  onToggleBookmarkHere: () => void;
+}
+
+export function ReaderToolbar({
+  title,
+  chapterTitle,
+  progressPct,
+  settings,
+  isBookmarked,
+  onBack,
+  onToggleToc,
+  onToggleSettings,
+  onToggleBookmarks,
+  onToggleBookmarkHere,
+}: ReaderToolbarProps): ReactNode {
+  const palette = resolvePalette(settings);
+
+  return (
+    <View style={[styles.bar, { backgroundColor: palette.chrome }]}>
+      <View style={styles.row}>
+        <TouchableOpacity
+          onPress={onBack}
+          hitSlop={12}
+          style={styles.iconButton}
+        >
+          <Text style={[styles.icon, { color: palette.text }]}>‹</Text>
+        </TouchableOpacity>
+
+        <View style={styles.titles}>
+          <Text
+            style={[styles.title, { color: palette.text }]}
+            numberOfLines={1}
+          >
+            {title}
+          </Text>
+          {chapterTitle ? (
+            <Text
+              style={[styles.chapter, { color: palette.text }]}
+              numberOfLines={1}
+            >
+              {chapterTitle}
+            </Text>
+          ) : null}
+        </View>
+
+        <TouchableOpacity
+          onPress={onToggleBookmarkHere}
+          hitSlop={12}
+          style={styles.iconButton}
+        >
+          <Text style={[styles.icon, { color: palette.text }]}>
+            {isBookmarked ? "★" : "☆"}
+          </Text>
+        </TouchableOpacity>
+        <TouchableOpacity
+          onPress={onToggleBookmarks}
+          hitSlop={12}
+          style={styles.iconButton}
+        >
+          <Text style={[styles.iconSmall, { color: palette.text }]}>≡</Text>
+        </TouchableOpacity>
+        <TouchableOpacity
+          onPress={onToggleToc}
+          hitSlop={12}
+          style={styles.iconButton}
+        >
+          <Text style={[styles.iconSmall, { color: palette.text }]}>⊟</Text>
+        </TouchableOpacity>
+        <TouchableOpacity
+          onPress={onToggleSettings}
+          hitSlop={12}
+          style={styles.iconButton}
+        >
+          <Text style={[styles.iconSmall, { color: palette.text }]}>Aa</Text>
+        </TouchableOpacity>
+      </View>
+
+      <View style={styles.progressTrack}>
+        <View
+          style={[
+            styles.progressFill,
+            { width: `${Math.min(100, Math.max(0, progressPct))}%` },
+          ]}
+        />
+      </View>
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  bar: {
+    paddingTop: 8,
+    paddingHorizontal: 8,
+    paddingBottom: 6,
+  },
+  row: {
+    flexDirection: "row",
+    alignItems: "center",
+  },
+  titles: {
+    flex: 1,
+    marginHorizontal: 8,
+  },
+  title: {
+    fontSize: 14,
+    fontWeight: "600",
+  },
+  chapter: {
+    fontSize: 11,
+    opacity: 0.7,
+  },
+  iconButton: {
+    paddingHorizontal: 8,
+    paddingVertical: 4,
+    minWidth: 28,
+    alignItems: "center",
+  },
+  icon: {
+    fontSize: 28,
+    lineHeight: 30,
+  },
+  iconSmall: {
+    fontSize: 17,
+    fontWeight: "600",
+  },
+  progressTrack: {
+    height: 3,
+    borderRadius: 2,
+    backgroundColor: "rgba(127,127,127,0.25)",
+    marginTop: 6,
+    overflow: "hidden",
+  },
+  progressFill: {
+    height: "100%",
+    backgroundColor: "#4f8ef7",
+  },
+});

mobile/src/components/reader/ReadingSettingsModal.tsx

@@ -0,0 +1,249 @@
+import { type ReactNode } from "react";
+import {
+  View,
+  Text,
+  TouchableOpacity,
+  StyleSheet,
+} from "react-native";
+import { resolvePalette, THEME_PALETTES } from "../../utils/epubTheme";
+import type {
+  FontFamily,
+  ReadingSettings,
+  ThemePreset,
+} from "../../types/reader";
+import { ReaderBottomSheet } from "./ReaderBottomSheet";
+
+const THEMES: ThemePreset[] = ["light", "sepia", "paper", "dark"];
+const FONTS: { value: FontFamily; label: string }[] = [
+  { value: "serif", label: "Serif" },
+  { value: "sans-serif", label: "Sans" },
+  { value: "monospace", label: "Mono" },
+];
+const FONT_SIZE_MIN = 12;
+const FONT_SIZE_MAX = 32;
+const LINE_HEIGHT_MIN = 1.2;
+const LINE_HEIGHT_MAX = 2.2;
+
+interface ReadingSettingsModalProps {
+  visible: boolean;
+  settings: ReadingSettings;
+  onChange: (patch: Partial<ReadingSettings>) => void;
+  onClose: () => void;
+}
+
+export function ReadingSettingsModal({
+  visible,
+  settings,
+  onChange,
+  onClose,
+}: ReadingSettingsModalProps): ReactNode {
+  const palette = resolvePalette(settings);
+
+  const adjustFontSize = (delta: number) => {
+    const next = Math.min(
+      FONT_SIZE_MAX,
+      Math.max(FONT_SIZE_MIN, settings.font_size + delta),
+    );
+    onChange({ font_size: next });
+  };
+
+  const adjustLineHeight = (delta: number) => {
+    const next = Math.min(
+      LINE_HEIGHT_MAX,
+      Math.max(
+        LINE_HEIGHT_MIN,
+        Math.round((settings.line_height + delta) * 10) / 10,
+      ),
+    );
+    onChange({ line_height: next });
+  };
+
+  return (
+    <ReaderBottomSheet
+      visible={visible}
+      title="Display"
+      chromeColor={palette.chrome}
+      textColor={palette.text}
+      onClose={onClose}
+      tall={false}
+      sheetStyle={styles.sheetBody}
+    >
+      <Text style={[styles.sectionLabel, { color: palette.text }]}>Theme</Text>
+      <View style={styles.rowWrap}>
+        {THEMES.map((theme) => {
+          const p = THEME_PALETTES[theme];
+          const active = settings.theme === theme;
+          return (
+            <TouchableOpacity
+              key={theme}
+              onPress={() =>
+                onChange({
+                  theme,
+                  background_color: p.background,
+                  text_color: p.text,
+                })
+              }
+              style={[
+                styles.themeSwatch,
+                { backgroundColor: p.background },
+                active && styles.themeSwatchActive,
+              ]}
+            >
+              <Text style={[styles.themeSwatchText, { color: p.text }]}>
+                Aa
+              </Text>
+            </TouchableOpacity>
+          );
+        })}
+      </View>
+
+      <Text style={[styles.sectionLabel, { color: palette.text }]}>Font</Text>
+      <View style={styles.rowWrap}>
+        {FONTS.map((font) => {
+          const active = settings.font_family === font.value;
+          return (
+            <TouchableOpacity
+              key={font.value}
+              onPress={() => onChange({ font_family: font.value })}
+              style={[styles.pill, active && styles.pillActive]}
+            >
+              <Text
+                style={[
+                  styles.pillText,
+                  { color: active ? "#fff" : palette.text },
+                ]}
+              >
+                {font.label}
+              </Text>
+            </TouchableOpacity>
+          );
+        })}
+      </View>
+
+      <Stepper
+        label="Font size"
+        value={`${settings.font_size}px`}
+        color={palette.text}
+        onDecrease={() => adjustFontSize(-1)}
+        onIncrease={() => adjustFontSize(1)}
+      />
+      <Stepper
+        label="Line spacing"
+        value={settings.line_height.toFixed(1)}
+        color={palette.text}
+        onDecrease={() => adjustLineHeight(-0.1)}
+        onIncrease={() => adjustLineHeight(0.1)}
+      />
+    </ReaderBottomSheet>
+  );
+}
+
+function Stepper({
+  label,
+  value,
+  color,
+  onDecrease,
+  onIncrease,
+}: {
+  label: string;
+  value: string;
+  color: string;
+  onDecrease: () => void;
+  onIncrease: () => void;
+}): ReactNode {
+  return (
+    <View style={styles.stepperRow}>
+      <Text style={[styles.sectionLabel, { color, marginBottom: 0 }]}>
+        {label}
+      </Text>
+      <View style={styles.stepperControls}>
+        <TouchableOpacity style={styles.stepperButton} onPress={onDecrease}>
+          <Text style={styles.stepperButtonText}>−</Text>
+        </TouchableOpacity>
+        <Text style={[styles.stepperValue, { color }]}>{value}</Text>
+        <TouchableOpacity style={styles.stepperButton} onPress={onIncrease}>
+          <Text style={styles.stepperButtonText}>+</Text>
+        </TouchableOpacity>
+      </View>
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  sheetBody: {
+    paddingHorizontal: 20,
+    paddingBottom: 32,
+  },
+  sectionLabel: {
+    fontSize: 13,
+    fontWeight: "600",
+    marginBottom: 8,
+    marginTop: 8,
+    opacity: 0.8,
+  },
+  rowWrap: {
+    flexDirection: "row",
+    flexWrap: "wrap",
+    gap: 10,
+  },
+  themeSwatch: {
+    width: 56,
+    height: 48,
+    borderRadius: 10,
+    justifyContent: "center",
+    alignItems: "center",
+    borderWidth: 2,
+    borderColor: "transparent",
+  },
+  themeSwatchActive: {
+    borderColor: "#4f8ef7",
+  },
+  themeSwatchText: {
+    fontSize: 16,
+    fontWeight: "600",
+  },
+  pill: {
+    paddingHorizontal: 16,
+    paddingVertical: 8,
+    borderRadius: 20,
+    borderWidth: 1,
+    borderColor: "rgba(127,127,127,0.4)",
+  },
+  pillActive: {
+    backgroundColor: "#4f8ef7",
+    borderColor: "#4f8ef7",
+  },
+  pillText: {
+    fontSize: 14,
+    fontWeight: "600",
+  },
+  stepperRow: {
+    flexDirection: "row",
+    alignItems: "center",
+    justifyContent: "space-between",
+    marginTop: 16,
+  },
+  stepperControls: {
+    flexDirection: "row",
+    alignItems: "center",
+  },
+  stepperButton: {
+    width: 36,
+    height: 36,
+    borderRadius: 18,
+    backgroundColor: "rgba(127,127,127,0.2)",
+    justifyContent: "center",
+    alignItems: "center",
+  },
+  stepperButtonText: {
+    fontSize: 20,
+    fontWeight: "700",
+    color: "#4f8ef7",
+  },
+  stepperValue: {
+    minWidth: 56,
+    textAlign: "center",
+    fontSize: 15,
+    fontWeight: "600",
+  },
+});

mobile/src/components/reader/TocModal.tsx

@@ -0,0 +1,111 @@
+import { type ReactNode } from "react";
+import {
+  Text,
+  FlatList,
+  TouchableOpacity,
+  StyleSheet,
+} from "react-native";
+import { resolvePalette } from "../../utils/epubTheme";
+import type { ReadingSettings } from "../../types/reader";
+import { ReaderBottomSheet } from "./ReaderBottomSheet";
+
+export interface TocItem {
+  id?: string;
+  label: string;
+  href: string;
+  subitems?: TocItem[];
+}
+
+interface FlatTocItem {
+  key: string;
+  label: string;
+  href: string;
+  depth: number;
+}
+
+function flatten(items: TocItem[], depth = 0, acc: FlatTocItem[] = []) {
+  items.forEach((item, index) => {
+    acc.push({
+      key: `${item.id ?? item.href}-${depth}-${index}`,
+      label: (item.label ?? "").trim() || "Untitled section",
+      href: item.href,
+      depth,
+    });
+    if (item.subitems?.length) {
+      flatten(item.subitems, depth + 1, acc);
+    }
+  });
+  return acc;
+}
+
+interface TocModalProps {
+  visible: boolean;
+  toc: TocItem[];
+  settings: ReadingSettings;
+  onSelect: (href: string) => void;
+  onClose: () => void;
+}
+
+export function TocModal({
+  visible,
+  toc,
+  settings,
+  onSelect,
+  onClose,
+}: TocModalProps): ReactNode {
+  const palette = resolvePalette(settings);
+  const data = flatten(toc);
+
+  return (
+    <ReaderBottomSheet
+      visible={visible}
+      title="Contents"
+      chromeColor={palette.chrome}
+      textColor={palette.text}
+      onClose={onClose}
+    >
+      <FlatList
+        data={data}
+        keyExtractor={(item) => item.key}
+        ListEmptyComponent={
+          <Text style={[styles.empty, { color: palette.text }]}>
+            No table of contents available.
+          </Text>
+        }
+        renderItem={({ item }) => (
+          <TouchableOpacity
+            style={styles.row}
+            onPress={() => onSelect(item.href)}
+          >
+            <Text
+              style={[
+                styles.rowText,
+                { color: palette.text, marginLeft: item.depth * 16 },
+              ]}
+              numberOfLines={2}
+            >
+              {item.label}
+            </Text>
+          </TouchableOpacity>
+        )}
+      />
+    </ReaderBottomSheet>
+  );
+}
+
+const styles = StyleSheet.create({
+  row: {
+    paddingVertical: 12,
+    paddingHorizontal: 16,
+    borderTopWidth: StyleSheet.hairlineWidth,
+    borderTopColor: "rgba(127,127,127,0.2)",
+  },
+  rowText: {
+    fontSize: 14,
+  },
+  empty: {
+    padding: 24,
+    textAlign: "center",
+    opacity: 0.7,
+  },
+});

mobile/src/hooks/index.ts

@@ -1,2 +0,0 @@
-export { useAuth } from "../context/AuthContext";
-export { useAsyncData } from "./useAsyncData";

mobile/src/hooks/useAsyncData.ts

@@ -1,33 +0,0 @@
-import { useState, useEffect, useCallback } from "react";
-
-/**
- * Generic async data fetching hook for mobile screens.
- */
-export function useAsyncData<T>(
-  fetcher: () => Promise<T>,
-  deps: unknown[] = [],
-) {
-  const [data, setData] = useState<T | null>(null);
-  const [loading, setLoading] = useState(true);
-  const [error, setError] = useState<Error | null>(null);
-
-  const execute = useCallback(async () => {
-    setLoading(true);
-    setError(null);
-    try {
-      const result = await fetcher();
-      setData(result);
-    } catch (err) {
-      setError(err instanceof Error ? err : new Error(String(err)));
-    } finally {
-      setLoading(false);
-    }
-    // eslint-disable-next-line react-hooks/exhaustive-deps
-  }, deps);
-
-  useEffect(() => {
-    execute();
-  }, [execute]);
-
-  return { data, loading, error, refetch: execute };
-}

mobile/src/hooks/useReadingSettings.ts

@@ -0,0 +1,82 @@
+import { useCallback, useEffect, useRef, useState } from "react";
+import {
+  getReadingSettings,
+  updateReadingSettings,
+} from "../api/reader";
+import type { ReadingSettings } from "../types/reader";
+
+const DEFAULT_READING_SETTINGS: ReadingSettings = {
+  font_family: "serif",
+  font_size: 18,
+  line_height: 1.5,
+  margin_width: 16,
+  background_color: "#fbfbf8",
+  text_color: "#2b2b2b",
+  brightness: 1,
+  orientation_lock: "auto",
+  theme: "paper",
+  created_at: "",
+  updated_at: "",
+};
+
+const SAVE_DEBOUNCE_MS = 600;
+
+interface UseReadingSettingsReturn {
+  settings: ReadingSettings;
+  loaded: boolean;
+  updateSettings: (patch: Partial<ReadingSettings>) => void;
+}
+
+/**
+ * Loads the user's reader settings and persists changes with a debounce.
+ * Mirrors frontend/src/hooks/useReadingSettings.ts behavior.
+ */
+export function useReadingSettings(): UseReadingSettingsReturn {
+  const [settings, setSettings] = useState<ReadingSettings>(
+    DEFAULT_READING_SETTINGS,
+  );
+  const [loaded, setLoaded] = useState(false);
+  const pendingRef = useRef<Partial<ReadingSettings>>({});
+  const timerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
+
+  useEffect(() => {
+    let active = true;
+    getReadingSettings()
+      .then((data) => {
+        if (active) {
+          setSettings(data);
+        }
+      })
+      .catch(() => {
+        /* keep defaults if the request fails */
+      })
+      .finally(() => {
+        if (active) {
+          setLoaded(true);
+        }
+      });
+    return () => {
+      active = false;
+      if (timerRef.current) {
+        clearTimeout(timerRef.current);
+      }
+    };
+  }, []);
+
+  const updateSettings = useCallback((patch: Partial<ReadingSettings>) => {
+    setSettings((prev) => ({ ...prev, ...patch }));
+    pendingRef.current = { ...pendingRef.current, ...patch };
+    if (timerRef.current) {
+      clearTimeout(timerRef.current);
+    }
+    timerRef.current = setTimeout(() => {
+      const body = pendingRef.current;
+      pendingRef.current = {};
+      updateReadingSettings(body).catch(() => {
+        /* ignore transient save failures */
+      });
+    }, SAVE_DEBOUNCE_MS);
+  }, []);
+
+  return { settings, loaded, updateSettings };
+}

mobile/src/navigation/AppNavigator.tsx

@@ -1,45 +0,0 @@
-import { type ReactNode } from "react";
-import { NavigationContainer } from "@react-navigation/native";
-import { createNativeStackNavigator } from "@react-navigation/native-stack";
-import { useAuth } from "../context/AuthContext";
-import LoginScreen from "../screens/LoginScreen";
-import RegisterScreen from "../screens/RegisterScreen";
-import MainTabs from "./MainTabs";
-
-export type AuthStackParamList = {
-  Login: undefined;
-  Register: undefined;
-};
-
-export type RootStackParamList = {
-  Auth: undefined;
-  Main: undefined;
-};
-
-const RootStack = createNativeStackNavigator<RootStackParamList>();
-const AuthStack = createNativeStackNavigator<AuthStackParamList>();
-
-function AuthNavigator(): ReactNode {
-  return (
-    <AuthStack.Navigator screenOptions={{ headerShown: false }}>
-      <AuthStack.Screen name="Login" component={LoginScreen} />
-      <AuthStack.Screen name="Register" component={RegisterScreen} />
-    </AuthStack.Navigator>
-  );
-}
-
-export default function AppNavigator(): ReactNode {
-  const { state } = useAuth();
-
-  return (
-    <NavigationContainer>
-      <RootStack.Navigator screenOptions={{ headerShown: false }}>
-        {state.isAuthenticated ? (
-          <RootStack.Screen name="Main" component={MainTabs} />
-        ) : (
-          <RootStack.Screen name="Auth" component={AuthNavigator} />
-        )}
-      </RootStack.Navigator>
-    </NavigationContainer>
-  );
-}

mobile/src/navigation/AppStack.tsx

@@ -0,0 +1,36 @@
+import React from "react";
+import { createNativeStackNavigator } from "@react-navigation/native-stack";
+import { MainNavigator } from "./MainNavigator";
+import BookDetailScreen from "../screens/BookDetailScreen";
+import ReaderScreen from "../screens/ReaderScreen";
+import type { AppStackParamList } from "../types";
+
+const Stack = createNativeStackNavigator<AppStackParamList>();
+
+export function AppStack() {
+  return (
+    <Stack.Navigator
+      screenOptions={{
+        headerStyle: { backgroundColor: "#fff" },
+        headerTitleStyle: { fontWeight: "600", color: "#1a1a2e" },
+        headerTintColor: "#4a6cf7",
+      }}
+    >
+      <Stack.Screen
+        name="Tabs"
+        component={MainNavigator}
+        options={{ headerShown: false }}
+      />
+      <Stack.Screen
+        name="BookDetail"
+        component={BookDetailScreen}
+        options={{ title: "" }}
+      />
+      <Stack.Screen
+        name="Reader"
+        component={ReaderScreen}
+        options={{ headerShown: false }}
+      />
+    </Stack.Navigator>
+  );
+}

mobile/src/navigation/AuthNavigator.tsx

@@ -3,7 +3,7 @@ import { createNativeStackNavigator } from "@react-navigation/native-stack";
 import LoginScreen from "../screens/LoginScreen";
 import RegisterScreen from "../screens/RegisterScreen";
 
-export type AuthStackParamList = {
+type AuthStackParamList = {
   Login: undefined;
   Register: undefined;
 };

mobile/src/navigation/MainTabs.tsx

@@ -1,55 +0,0 @@
-import { type ReactNode } from "react";
-import { createBottomTabNavigator } from "@react-navigation/bottom-tabs";
-import { Text } from "react-native";
-import LibraryScreen from "../screens/LibraryScreen";
-import SearchScreen from "../screens/SearchScreen";
-import SettingsScreen from "../screens/SettingsScreen";
-
-export type MainTabParamList = {
-  Library: undefined;
-  Search: undefined;
-  Settings: undefined;
-};
-
-const Tab = createBottomTabNavigator<MainTabParamList>();
-
-function TabIcon({ label, focused }: { label: string; focused: boolean }) {
-  return (
-    <Text style={{ fontSize: 22, opacity: focused ? 1 : 0.5 }}>
-      {label === "Library" ? "📚" : label === "Search" ? "🔍" : "⚙️"}
-    </Text>
-  );
-}
-
-export default function MainTabs(): ReactNode {
-  return (
-    <Tab.Navigator
-      screenOptions={({ route }) => ({
-        tabBarIcon: ({ focused }: { focused: boolean }) => (
-          <TabIcon label={route.name} focused={focused} />
-        ),
-        tabBarActiveTintColor: "#4f8ef7",
-        tabBarInactiveTintColor: "#888",
-        headerStyle: { backgroundColor: "#1a1a2e" },
-        headerTintColor: "#fff",
-        tabBarStyle: { backgroundColor: "#1a1a2e", borderTopColor: "#333" },
-      })}
-    >
-      <Tab.Screen
-        name="Library"
-        component={LibraryScreen}
-        options={{ title: "My Library" }}
-      />
-      <Tab.Screen
-        name="Search"
-        component={SearchScreen}
-        options={{ title: "Search" }}
-      />
-      <Tab.Screen
-        name="Settings"
-        component={SettingsScreen}
-        options={{ title: "Settings" }}
-      />
-    </Tab.Navigator>
-  );
-}

mobile/src/navigation/RootNavigator.tsx

@@ -2,7 +2,7 @@ import React from "react";
 import { ActivityIndicator, View } from "react-native";
 import { useAuth } from "../context/AuthContext";
 import { AuthNavigator } from "./AuthNavigator";
-import { MainNavigator } from "./MainNavigator";
+import { AppStack } from "./AppStack";
 
 export function RootNavigator() {
   const { isLoading, isAuthenticated } = useAuth();
@@ -19,5 +19,5 @@ export function RootNavigator() {
     return <AuthNavigator />;
   }
 
-  return <MainNavigator />;
+  return <AppStack />;
 }

mobile/src/screens/AuthFormError.tsx

@@ -0,0 +1,11 @@
+import { type ReactNode } from "react";
+import { View, Text } from "react-native";
+import { authStyles } from "./authStyles";
+
+export function AuthFormError({ message }: { message: string }): ReactNode {
+  return (
+    <View style={authStyles.errorBox}>
+      <Text style={authStyles.errorText}>{message}</Text>
+    </View>
+  );
+}

mobile/src/screens/BookDetailScreen.tsx

@@ -0,0 +1,226 @@
+import { useState, useEffect, useCallback, type ReactNode } from "react";
+import {
+  View,
+  Text,
+  Image,
+  ScrollView,
+  TouchableOpacity,
+  StyleSheet,
+  ActivityIndicator,
+} from "react-native";
+import type { RouteProp } from "@react-navigation/native";
+import { ebooksApi } from "../api/ebooks";
+import { formatFileSize } from "@cloud-reader/shared";
+import type { EBookDetail } from "@cloud-reader/shared";
+import type { AppStackParamList } from "../types";
+
+type DetailRoute = RouteProp<AppStackParamList, "BookDetail">;
+
+export default function BookDetailScreen({
+  route,
+  navigation,
+}: {
+  route: DetailRoute;
+  navigation: any;
+}): ReactNode {
+  const { ebookId } = route.params;
+  const [book, setBook] = useState<EBookDetail | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState(false);
+
+  const load = useCallback(async () => {
+    try {
+      const { data } = await ebooksApi.get(ebookId);
+      setBook(data);
+    } catch {
+      setError(true);
+    } finally {
+      setLoading(false);
+    }
+  }, [ebookId]);
+
+  useEffect(() => {
+    load();
+  }, [load]);
+
+  if (loading) {
+    return (
+      <View style={styles.centered}>
+        <ActivityIndicator size="large" color="#4f8ef7" />
+      </View>
+    );
+  }
+
+  if (error || !book) {
+    return (
+      <View style={styles.centered}>
+        <Text style={styles.errorText}>Could not load this book.</Text>
+      </View>
+    );
+  }
+
+  const progressPct =
+    typeof book.progress?.current_position === "number"
+      ? Math.round(book.progress.current_position)
+      : 0;
+  const hasProgress = progressPct > 0;
+
+  return (
+    <ScrollView style={styles.container} contentContainerStyle={styles.content}>
+      <View style={styles.header}>
+        {book.cover_image ? (
+          <Image source={{ uri: book.cover_image }} style={styles.cover} />
+        ) : (
+          <View style={styles.cover}>
+            <Text style={styles.coverText}>
+              {book.title.charAt(0).toUpperCase()}
+            </Text>
+          </View>
+        )}
+        <Text style={styles.title}>{book.title}</Text>
+        <Text style={styles.author}>{book.author || "Unknown author"}</Text>
+      </View>
+
+      <View style={styles.metaRow}>
+        <MetaPill label="Format" value={book.format?.toUpperCase() || "—"} />
+        <MetaPill
+          label="Pages"
+          value={book.page_count ? String(book.page_count) : "—"}
+        />
+        <MetaPill label="Size" value={formatFileSize(book.file_size || 0)} />
+      </View>
+
+      {hasProgress && (
+        <View style={styles.progressWrap}>
+          <View style={styles.progressTrack}>
+            <View style={[styles.progressFill, { width: `${progressPct}%` }]} />
+          </View>
+          <Text style={styles.progressLabel}>{progressPct}% read</Text>
+        </View>
+      )}
+
+      <TouchableOpacity
+        style={styles.readButton}
+        onPress={() => navigation.navigate("Reader", { ebookId: book.id })}
+      >
+        <Text style={styles.readButtonText}>
+          {hasProgress ? "Resume reading" : "Start reading"}
+        </Text>
+      </TouchableOpacity>
+    </ScrollView>
+  );
+}
+
+function MetaPill({ label, value }: { label: string; value: string }): ReactNode {
+  return (
+    <View style={styles.metaPill}>
+      <Text style={styles.metaValue}>{value}</Text>
+      <Text style={styles.metaLabel}>{label}</Text>
+    </View>
+  );
+}
+
+const styles = StyleSheet.create({
+  container: {
+    flex: 1,
+    backgroundColor: "#0f0f23",
+  },
+  content: {
+    padding: 24,
+  },
+  centered: {
+    flex: 1,
+    justifyContent: "center",
+    alignItems: "center",
+    backgroundColor: "#0f0f23",
+    padding: 24,
+  },
+  header: {
+    alignItems: "center",
+    marginBottom: 24,
+  },
+  cover: {
+    width: 140,
+    height: 200,
+    borderRadius: 12,
+    backgroundColor: "#2a2a4e",
+    justifyContent: "center",
+    alignItems: "center",
+    marginBottom: 16,
+  },
+  coverText: {
+    fontSize: 56,
+    fontWeight: "bold",
+    color: "#4f8ef7",
+  },
+  title: {
+    fontSize: 22,
+    fontWeight: "700",
+    color: "#fff",
+    textAlign: "center",
+    marginBottom: 6,
+  },
+  author: {
+    fontSize: 15,
+    color: "#888",
+    textAlign: "center",
+  },
+  metaRow: {
+    flexDirection: "row",
+    justifyContent: "space-between",
+    marginBottom: 24,
+  },
+  metaPill: {
+    flex: 1,
+    backgroundColor: "#1a1a2e",
+    borderRadius: 10,
+    paddingVertical: 12,
+    marginHorizontal: 4,
+    alignItems: "center",
+    borderWidth: 1,
+    borderColor: "#333",
+  },
+  metaValue: {
+    fontSize: 15,
+    fontWeight: "600",
+    color: "#fff",
+  },
+  metaLabel: {
+    fontSize: 12,
+    color: "#666",
+    marginTop: 2,
+  },
+  progressWrap: {
+    marginBottom: 24,
+  },
+  progressTrack: {
+    height: 6,
+    borderRadius: 3,
+    backgroundColor: "#1a1a2e",
+    overflow: "hidden",
+  },
+  progressFill: {
+    height: "100%",
+    backgroundColor: "#4f8ef7",
+  },
+  progressLabel: {
+    fontSize: 12,
+    color: "#888",
+    marginTop: 6,
+  },
+  readButton: {
+    backgroundColor: "#4f8ef7",
+    borderRadius: 10,
+    paddingVertical: 16,
+    alignItems: "center",
+  },
+  readButtonText: {
+    color: "#fff",
+    fontSize: 16,
+    fontWeight: "600",
+  },
+  errorText: {
+    color: "#888",
+    fontSize: 15,
+  },
+});

mobile/src/screens/LibraryScreen.tsx

@@ -2,34 +2,31 @@ import { useState, useEffect, useCallback, type ReactNode } from "react";
 import {
   View,
   Text,
+  Image,
   FlatList,
   TouchableOpacity,
   StyleSheet,
   ActivityIndicator,
   RefreshControl,
 } from "react-native";
-import { fetchBooks } from "../api/books";
+import { ebooksApi } from "../api/ebooks";
-import type { Book, PaginatedResponse } from "@cloud-reader/shared";
+import type { EBookListItem } from "@cloud-reader/shared";
 
-export default function LibraryScreen({ navigation }: { navigation: any }): ReactNode {
+export default function LibraryScreen({
-  const [books, setBooks] = useState<Book[]>([]);
+  navigation,
+}: {
+  navigation: any;
+}): ReactNode {
+  const [books, setBooks] = useState<EBookListItem[]>([]);
   const [loading, setLoading] = useState(true);
   const [refreshing, setRefreshing] = useState(false);
-  const [page, setPage] = useState(1);
-  const [hasMore, setHasMore] = useState(true);
 
-  const loadBooks = useCallback(async (pageNum: number, isRefresh = false) => {
+  const loadBooks = useCallback(async () => {
     try {
-      const data: PaginatedResponse<Book> = await fetchBooks(pageNum);
+      const { data } = await ebooksApi.list();
-      if (isRefresh) {
+      setBooks(data.results);
-        setBooks(data.results);
-      } else {
-        setBooks((prev) => [...prev, ...data.results]);
-      }
-      setHasMore(data.next !== null);
-      setPage(pageNum);
     } catch {
-      // Silent error for now
+      // Silent error for now; pull-to-refresh lets the user retry.
     } finally {
       setLoading(false);
       setRefreshing(false);
@@ -37,44 +34,49 @@ export default function LibraryScreen({ navigation }: { navigation: any }): Reac
   }, []);
 
   useEffect(() => {
-    loadBooks(1, true);
+    loadBooks();
   }, [loadBooks]);
 
   const onRefresh = () => {
     setRefreshing(true);
-    loadBooks(1, true);
+    loadBooks();
   };
 
-  const loadMore = () => {
+  const renderBook = ({ item }: { item: EBookListItem }) => {
-    if (hasMore && !loading) {
+    const progress =
-      loadBooks(page + 1);
+      typeof item.progress === "number"
-    }
+        ? Math.round(item.progress)
+        : null;
+    return (
+      <TouchableOpacity
+        style={styles.bookCard}
+        onPress={() => navigation.navigate("BookDetail", { ebookId: item.id })}
+      >
+        {item.cover_image ? (
+          <Image source={{ uri: item.cover_image }} style={styles.bookCover} />
+        ) : (
+          <View style={styles.bookCover}>
+            <Text style={styles.coverText}>
+              {item.title.charAt(0).toUpperCase()}
+            </Text>
+          </View>
+        )}
+        <View style={styles.bookInfo}>
+          <Text style={styles.bookTitle} numberOfLines={2}>
+            {item.title}
+          </Text>
+          <Text style={styles.bookAuthor} numberOfLines={1}>
+            {item.author || "Unknown author"}
+          </Text>
+          <Text style={styles.bookMeta}>
+            {item.format?.toUpperCase()}
+            {progress !== null ? ` · ${progress}% read` : ""}
+          </Text>
+        </View>
+      </TouchableOpacity>
+    );
   };
 
-  const renderBook = ({ item }: { item: Book }) => (
-    <TouchableOpacity
-      style={styles.bookCard}
-      onPress={() =>
-        navigation.navigate("BookDetail", { bookId: item.id })
-      }
-    >
-      <View style={styles.bookCover}>
-        <Text style={styles.coverText}>
-          {item.title.charAt(0).toUpperCase()}
-        </Text>
-      </View>
-      <View style={styles.bookInfo}>
-        <Text style={styles.bookTitle} numberOfLines={1}>
-          {item.title}
-        </Text>
-        <Text style={styles.bookAuthor} numberOfLines={1}>
-          {item.author}
-        </Text>
-        <Text style={styles.bookPages}>{item.total_pages} pages</Text>
-      </View>
-    </TouchableOpacity>
-  );
-
   if (loading && books.length === 0) {
     return (
       <View style={styles.centered}>
@@ -88,9 +90,7 @@ export default function LibraryScreen({ navigation }: { navigation: any }): Reac
       <FlatList
         data={books}
         renderItem={renderBook}
-        keyExtractor={(item) => item.id}
+        keyExtractor={(item) => String(item.id)}
-        onEndReached={loadMore}
-        onEndReachedThreshold={0.5}
         contentContainerStyle={styles.list}
         refreshControl={
           <RefreshControl
@@ -103,7 +103,7 @@ export default function LibraryScreen({ navigation }: { navigation: any }): Reac
           <View style={styles.centered}>
             <Text style={styles.emptyText}>Your library is empty</Text>
             <Text style={styles.emptySubtext}>
-              Add books to get started
+              Upload books from the web app to get started
             </Text>
           </View>
         }
@@ -125,6 +125,7 @@ const styles = StyleSheet.create({
   },
   list: {
     padding: 16,
+    flexGrow: 1,
   },
   bookCard: {
     flexDirection: "row",
@@ -164,7 +165,7 @@ const styles = StyleSheet.create({
     color: "#888",
     marginBottom: 4,
   },
-  bookPages: {
+  bookMeta: {
     fontSize: 12,
     color: "#666",
   },
@@ -177,5 +178,6 @@ const styles = StyleSheet.create({
   emptySubtext: {
     fontSize: 14,
     color: "#666",
+    textAlign: "center",
   },
-});
+});

mobile/src/screens/LoginScreen.tsx

@@ -4,29 +4,31 @@ import {
   Text,
   TextInput,
   TouchableOpacity,
-  StyleSheet,
   Alert,
   ActivityIndicator,
   KeyboardAvoidingView,
   Platform,
 } from "react-native";
 import { useAuth } from "../context/AuthContext";
-import { isValidEmail } from "@cloud-reader/shared";
+import { authStyles } from "./authStyles";
+import { AuthFormError } from "./AuthFormError";
+import { requireValidEmail } from "./authValidation";
 
-export default function LoginScreen({ navigation }: { navigation: any }): ReactNode {
+export default function LoginScreen({
-  const { state, login, clearError } = useAuth();
+  navigation,
+}: {
+  navigation: any;
+}): ReactNode {
+  const { login } = useAuth();
   const [email, setEmail] = useState("");
   const [password, setPassword] = useState("");
+  const [error, setError] = useState<string | null>(null);
+  const [submitting, setSubmitting] = useState(false);
 
   const handleLogin = async () => {
-    clearError();
+    setError(null);
 
-    if (!email.trim()) {
+    if (!requireValidEmail(email)) {
-      Alert.alert("Validation Error", "Please enter your email.");
-      return;
-    }
-    if (!isValidEmail(email.trim())) {
-      Alert.alert("Validation Error", "Please enter a valid email address.");
       return;
     }
     if (!password) {
@@ -34,30 +36,29 @@ export default function LoginScreen({ navigation }: { navigation: any }): ReactN
       return;
     }
 
+    setSubmitting(true);
     try {
       await login(email.trim(), password);
     } catch {
-      // Error handled in context
+      setError("Invalid email or password.");
+    } finally {
+      setSubmitting(false);
     }
   };
 
   return (
     <KeyboardAvoidingView
-      style={styles.container}
+      style={authStyles.container}
       behavior={Platform.OS === "ios" ? "padding" : "height"}
     >
-      <View style={styles.inner}>
+      <View style={authStyles.inner}>
-        <Text style={styles.title}>Cloud Reader</Text>
+        <Text style={authStyles.title}>Cloud Reader</Text>
-        <Text style={styles.subtitle}>Sign in to your account</Text>
+        <Text style={authStyles.subtitle}>Sign in to your account</Text>
 
-        {state.error && (
+        {error ? <AuthFormError message={error} /> : null}
-          <View style={styles.errorBox}>
-            <Text style={styles.errorText}>{state.error}</Text>
-          </View>
-        )}
 
         <TextInput
-          style={styles.input}
+          style={authStyles.input}
           placeholder="Email"
           placeholderTextColor="#666"
           value={email}
@@ -68,7 +69,7 @@ export default function LoginScreen({ navigation }: { navigation: any }): ReactN
         />
 
         <TextInput
-          style={styles.input}
+          style={authStyles.input}
           placeholder="Password"
           placeholderTextColor="#666"
           value={password}
@@ -77,97 +78,24 @@ export default function LoginScreen({ navigation }: { navigation: any }): ReactN
         />
 
         <TouchableOpacity
-          style={[styles.button, state.isLoading && styles.buttonDisabled]}
+          style={[authStyles.button, submitting && authStyles.buttonDisabled]}
           onPress={handleLogin}
-          disabled={state.isLoading}
+          disabled={submitting}
         >
-          {state.isLoading ? (
+          {submitting ? (
             <ActivityIndicator color="#fff" />
           ) : (
-            <Text style={styles.buttonText}>Sign In</Text>
+            <Text style={authStyles.buttonText}>Sign In</Text>
           )}
         </TouchableOpacity>
 
         <TouchableOpacity onPress={() => navigation.navigate("Register")}>
-          <Text style={styles.linkText}>
+          <Text style={authStyles.linkText}>
             Don't have an account?{" "}
-            <Text style={styles.linkBold}>Sign Up</Text>
+            <Text style={authStyles.linkBold}>Sign Up</Text>
           </Text>
         </TouchableOpacity>
       </View>
     </KeyboardAvoidingView>
   );
 }
-
-const styles = StyleSheet.create({
-  container: {
-    flex: 1,
-    backgroundColor: "#0f0f23",
-  },
-  inner: {
-    flex: 1,
-    justifyContent: "center",
-    paddingHorizontal: 24,
-  },
-  title: {
-    fontSize: 32,
-    fontWeight: "bold",
-    color: "#fff",
-    textAlign: "center",
-    marginBottom: 8,
-  },
-  subtitle: {
-    fontSize: 16,
-    color: "#888",
-    textAlign: "center",
-    marginBottom: 32,
-  },
-  input: {
-    backgroundColor: "#1a1a2e",
-    borderRadius: 8,
-    padding: 16,
-    fontSize: 16,
-    color: "#fff",
-    marginBottom: 12,
-    borderWidth: 1,
-    borderColor: "#333",
-  },
-  button: {
-    backgroundColor: "#4f8ef7",
-    borderRadius: 8,
-    padding: 16,
-    alignItems: "center",
-    marginTop: 8,
-    marginBottom: 24,
-  },
-  buttonDisabled: {
-    opacity: 0.6,
-  },
-  buttonText: {
-    color: "#fff",
-    fontSize: 16,
-    fontWeight: "600",
-  },
-  errorBox: {
-    backgroundColor: "rgba(255, 69, 58, 0.15)",
-    borderRadius: 8,
-    padding: 12,
-    marginBottom: 16,
-    borderWidth: 1,
-    borderColor: "rgba(255, 69, 58, 0.3)",
-  },
-  errorText: {
-    color: "#ff453a",
-    fontSize: 14,
-    textAlign: "center",
-  },
-  linkText: {
-    color: "#888",
-    textAlign: "center",
-    fontSize: 14,
-  },
-  linkBold: {
-    color: "#4f8ef7",
-    fontWeight: "600",
-  },
-});

mobile/src/screens/ReaderScreen.tsx

@@ -0,0 +1,133 @@
+import { useEffect, useState, type ReactNode } from "react";
+import {
+  View,
+  Text,
+  TouchableOpacity,
+  ActivityIndicator,
+  StyleSheet,
+} from "react-native";
+import { SafeAreaView } from "react-native-safe-area-context";
+import type { RouteProp } from "@react-navigation/native";
+import type { EBookDetail } from "@cloud-reader/shared";
+import { ebooksApi } from "../api/ebooks";
+import { EpubReaderView } from "../components/reader/EpubReaderView";
+import type { AppStackParamList } from "../types";
+
+type ReaderRoute = RouteProp<AppStackParamList, "Reader">;
+
+export default function ReaderScreen({
+  route,
+  navigation,
+}: {
+  route: ReaderRoute;
+  navigation: any;
+}): ReactNode {
+  const { ebookId } = route.params;
+  const [book, setBook] = useState<EBookDetail | null>(null);
+  const [loading, setLoading] = useState(true);
+  const [error, setError] = useState(false);
+
+  useEffect(() => {
+    let active = true;
+    ebooksApi
+      .get(ebookId)
+      .then(({ data }) => {
+        if (active) setBook(data);
+      })
+      .catch(() => {
+        if (active) setError(true);
+      })
+      .finally(() => {
+        if (active) setLoading(false);
+      });
+    return () => {
+      active = false;
+    };
+  }, [ebookId]);
+
+  if (loading) {
+    return (
+      <View style={styles.centered}>
+        <ActivityIndicator size="large" color="#4f8ef7" />
+      </View>
+    );
+  }
+
+  if (error || !book) {
+    return (
+      <SafeAreaView style={styles.centered} edges={["top", "bottom"]}>
+        <Text style={styles.message}>Could not open this book.</Text>
+        <TouchableOpacity
+          style={styles.backButton}
+          onPress={() => navigation.goBack()}
+        >
+          <Text style={styles.backText}>Go back</Text>
+        </TouchableOpacity>
+      </SafeAreaView>
+    );
+  }
+
+  const format = (book.format ?? "").toLowerCase();
+
+  if (format !== "epub") {
+    return (
+      <SafeAreaView style={styles.centered} edges={["top", "bottom"]}>
+        <Text style={styles.placeholderTitle}>PDF reading is coming soon</Text>
+        <Text style={styles.message}>
+          “{book.title}” is a {format.toUpperCase() || "non-EPUB"} file. PDF
+          reading isn&apos;t available on mobile yet — open it in the web reader
+          for now.
+        </Text>
+        <TouchableOpacity
+          style={styles.backButton}
+          onPress={() => navigation.goBack()}
+        >
+          <Text style={styles.backText}>Go back</Text>
+        </TouchableOpacity>
+      </SafeAreaView>
+    );
+  }
+
+  return (
+    <EpubReaderView
+      book={book}
+      ebookId={ebookId}
+      onClose={() => navigation.goBack()}
+    />
+  );
+}
+
+const styles = StyleSheet.create({
+  centered: {
+    flex: 1,
+    justifyContent: "center",
+    alignItems: "center",
+    backgroundColor: "#0f0f23",
+    padding: 24,
+  },
+  placeholderTitle: {
+    fontSize: 20,
+    fontWeight: "700",
+    color: "#fff",
+    marginBottom: 12,
+    textAlign: "center",
+  },
+  message: {
+    fontSize: 15,
+    color: "#aaa",
+    textAlign: "center",
+    lineHeight: 22,
+  },
+  backButton: {
+    marginTop: 24,
+    backgroundColor: "#4f8ef7",
+    borderRadius: 10,
+    paddingHorizontal: 24,
+    paddingVertical: 12,
+  },
+  backText: {
+    color: "#fff",
+    fontSize: 15,
+    fontWeight: "600",
+  },
+});

mobile/src/screens/RegisterScreen.tsx

@@ -1,10 +1,8 @@
 import { useState, type ReactNode } from "react";
 import {
-  View,
   Text,
   TextInput,
   TouchableOpacity,
-  StyleSheet,
   Alert,
   ActivityIndicator,
   KeyboardAvoidingView,
@@ -12,40 +10,39 @@ import {
   ScrollView,
 } from "react-native";
 import { useAuth } from "../context/AuthContext";
-import {
+import { isStrongPassword } from "@cloud-reader/shared";
-  isValidEmail,
+import { authStyles } from "./authStyles";
-  validatePasswordStrength,
+import { AuthFormError } from "./AuthFormError";
-} from "@cloud-reader/shared";
+import { requireValidEmail } from "./authValidation";
 
 export default function RegisterScreen({
   navigation,
 }: {
   navigation: any;
 }): ReactNode {
-  const { state, register, clearError } = useAuth();
+  const { register } = useAuth();
   const [username, setUsername] = useState("");
   const [email, setEmail] = useState("");
   const [password, setPassword] = useState("");
   const [confirmPassword, setConfirmPassword] = useState("");
+  const [error, setError] = useState<string | null>(null);
+  const [submitting, setSubmitting] = useState(false);
 
   const handleRegister = async () => {
-    clearError();
+    setError(null);
 
     if (!username.trim()) {
       Alert.alert("Validation Error", "Please enter a username.");
       return;
     }
-    if (!email.trim()) {
+    if (!requireValidEmail(email)) {
-      Alert.alert("Validation Error", "Please enter your email.");
       return;
     }
-    if (!isValidEmail(email.trim())) {
+    if (!isStrongPassword(password)) {
-      Alert.alert("Validation Error", "Please enter a valid email address.");
+      Alert.alert(
-      return;
+        "Validation Error",
-    }
+        "Password must be at least 8 characters and include uppercase, lowercase, and a number.",
-    const passwordError = validatePasswordStrength(password);
+      );
-    if (passwordError) {
-      Alert.alert("Validation Error", passwordError);
       return;
     }
     if (password !== confirmPassword) {
@@ -53,30 +50,29 @@ export default function RegisterScreen({
       return;
     }
 
+    setSubmitting(true);
     try {
-      await register(email.trim(), password, username.trim());
+      await register(email.trim(), username.trim(), password);
     } catch {
-      // Error handled in context
+      setError("Could not create the account. Try a different email.");
+    } finally {
+      setSubmitting(false);
     }
   };
 
   return (
     <KeyboardAvoidingView
-      style={styles.container}
+      style={authStyles.container}
       behavior={Platform.OS === "ios" ? "padding" : "height"}
     >
-      <ScrollView contentContainerStyle={styles.inner}>
+      <ScrollView contentContainerStyle={authStyles.innerScroll}>
-        <Text style={styles.title}>Create Account</Text>
+        <Text style={authStyles.titleCompact}>Create Account</Text>
-        <Text style={styles.subtitle}>Join Cloud Reader</Text>
+        <Text style={authStyles.subtitle}>Join Cloud Reader</Text>
 
-        {state.error && (
+        {error ? <AuthFormError message={error} /> : null}
-          <View style={styles.errorBox}>
-            <Text style={styles.errorText}>{state.error}</Text>
-          </View>
-        )}
 
         <TextInput
-          style={styles.input}
+          style={authStyles.input}
           placeholder="Username"
           placeholderTextColor="#666"
           value={username}
@@ -86,7 +82,7 @@ export default function RegisterScreen({
         />
 
         <TextInput
-          style={styles.input}
+          style={authStyles.input}
           placeholder="Email"
           placeholderTextColor="#666"
           value={email}
@@ -97,7 +93,7 @@ export default function RegisterScreen({
         />
 
         <TextInput
-          style={styles.input}
+          style={authStyles.input}
           placeholder="Password"
           placeholderTextColor="#666"
           value={password}
@@ -106,7 +102,7 @@ export default function RegisterScreen({
         />
 
         <TextInput
-          style={styles.input}
+          style={authStyles.input}
           placeholder="Confirm Password"
           placeholderTextColor="#666"
           value={confirmPassword}
@@ -115,98 +111,24 @@ export default function RegisterScreen({
         />
 
         <TouchableOpacity
-          style={[styles.button, state.isLoading && styles.buttonDisabled]}
+          style={[authStyles.button, submitting && authStyles.buttonDisabled]}
           onPress={handleRegister}
-          disabled={state.isLoading}
+          disabled={submitting}
         >
-          {state.isLoading ? (
+          {submitting ? (
             <ActivityIndicator color="#fff" />
           ) : (
-            <Text style={styles.buttonText}>Create Account</Text>
+            <Text style={authStyles.buttonText}>Create Account</Text>
           )}
         </TouchableOpacity>
 
         <TouchableOpacity onPress={() => navigation.goBack()}>
-          <Text style={styles.linkText}>
+          <Text style={authStyles.linkText}>
             Already have an account?{" "}
-            <Text style={styles.linkBold}>Sign In</Text>
+            <Text style={authStyles.linkBold}>Sign In</Text>
           </Text>
         </TouchableOpacity>
       </ScrollView>
     </KeyboardAvoidingView>
   );
 }
-
-const styles = StyleSheet.create({
-  container: {
-    flex: 1,
-    backgroundColor: "#0f0f23",
-  },
-  inner: {
-    flexGrow: 1,
-    justifyContent: "center",
-    paddingHorizontal: 24,
-    paddingVertical: 48,
-  },
-  title: {
-    fontSize: 28,
-    fontWeight: "bold",
-    color: "#fff",
-    textAlign: "center",
-    marginBottom: 8,
-  },
-  subtitle: {
-    fontSize: 16,
-    color: "#888",
-    textAlign: "center",
-    marginBottom: 32,
-  },
-  input: {
-    backgroundColor: "#1a1a2e",
-    borderRadius: 8,
-    padding: 16,
-    fontSize: 16,
-    color: "#fff",
-    marginBottom: 12,
-    borderWidth: 1,
-    borderColor: "#333",
-  },
-  button: {
-    backgroundColor: "#4f8ef7",
-    borderRadius: 8,
-    padding: 16,
-    alignItems: "center",
-    marginTop: 8,
-    marginBottom: 24,
-  },
-  buttonDisabled: {
-    opacity: 0.6,
-  },
-  buttonText: {
-    color: "#fff",
-    fontSize: 16,
-    fontWeight: "600",
-  },
-  errorBox: {
-    backgroundColor: "rgba(255, 69, 58, 0.15)",
-    borderRadius: 8,
-    padding: 12,
-    marginBottom: 16,
-    borderWidth: 1,
-    borderColor: "rgba(255, 69, 58, 0.3)",
-  },
-  errorText: {
-    color: "#ff453a",
-    fontSize: 14,
-    textAlign: "center",
-  },
-  linkText: {
-    color: "#888",
-    textAlign: "center",
-    fontSize: 14,
-  },
-  linkBold: {
-    color: "#4f8ef7",
-    fontWeight: "600",
-  },
-});

mobile/src/screens/SettingsScreen.tsx

@@ -9,7 +9,7 @@ import {
 import { useAuth } from "../context/AuthContext";
 
 export default function SettingsScreen(): ReactNode {
-  const { state, logout } = useAuth();
+  const { user, logout } = useAuth();
 
   const handleLogout = () => {
     Alert.alert("Logout", "Are you sure you want to sign out?", [
@@ -24,11 +24,11 @@ export default function SettingsScreen(): ReactNode {
         <Text style={styles.sectionTitle}>Account</Text>
         <View style={styles.infoRow}>
           <Text style={styles.label}>Username</Text>
-          <Text style={styles.value}>{state.user?.username ?? "—"}</Text>
+          <Text style={styles.value}>{user?.username ?? "—"}</Text>
         </View>
         <View style={styles.infoRow}>
           <Text style={styles.label}>Email</Text>
-          <Text style={styles.value}>{state.user?.email ?? "—"}</Text>
+          <Text style={styles.value}>{user?.email ?? "—"}</Text>
         </View>
       </View>
 

mobile/src/screens/authStyles.ts

@@ -0,0 +1,88 @@
+import { StyleSheet } from "react-native";
+
+/** Shared layout/styles for Login and Register screens. */
+export const authStyles = StyleSheet.create({
+  container: {
+    flex: 1,
+    backgroundColor: "#0f0f23",
+  },
+  inner: {
+    flex: 1,
+    justifyContent: "center",
+    paddingHorizontal: 24,
+  },
+  innerScroll: {
+    flexGrow: 1,
+    justifyContent: "center",
+    paddingHorizontal: 24,
+    paddingVertical: 48,
+  },
+  title: {
+    fontSize: 32,
+    fontWeight: "bold",
+    color: "#fff",
+    textAlign: "center",
+    marginBottom: 8,
+  },
+  titleCompact: {
+    fontSize: 28,
+    fontWeight: "bold",
+    color: "#fff",
+    textAlign: "center",
+    marginBottom: 8,
+  },
+  subtitle: {
+    fontSize: 16,
+    color: "#888",
+    textAlign: "center",
+    marginBottom: 32,
+  },
+  input: {
+    backgroundColor: "#1a1a2e",
+    borderRadius: 8,
+    padding: 16,
+    fontSize: 16,
+    color: "#fff",
+    marginBottom: 12,
+    borderWidth: 1,
+    borderColor: "#333",
+  },
+  button: {
+    backgroundColor: "#4f8ef7",
+    borderRadius: 8,
+    padding: 16,
+    alignItems: "center",
+    marginTop: 8,
+    marginBottom: 24,
+  },
+  buttonDisabled: {
+    opacity: 0.6,
+  },
+  buttonText: {
+    color: "#fff",
+    fontSize: 16,
+    fontWeight: "600",
+  },
+  errorBox: {
+    backgroundColor: "rgba(255, 69, 58, 0.15)",
+    borderRadius: 8,
+    padding: 12,
+    marginBottom: 16,
+    borderWidth: 1,
+    borderColor: "rgba(255, 69, 58, 0.3)",
+  },
+  errorText: {
+    color: "#ff453a",
+    fontSize: 14,
+    textAlign: "center",
+  },
+  linkText: {
+    color: "#888",
+    textAlign: "center",
+    fontSize: 14,
+  },
+  linkBold: {
+    color: "#4f8ef7",
+    fontWeight: "600",
+  },
+});

mobile/src/screens/authValidation.ts

@@ -0,0 +1,15 @@
+import { Alert } from "react-native";
+import { isValidEmail } from "@cloud-reader/shared";
+
+/** Returns true when email is non-empty and well-formed. */
+export function requireValidEmail(email: string): boolean {
+  if (!email.trim()) {
+    Alert.alert("Validation Error", "Please enter your email.");
+    return false;
+  }
+  if (!isValidEmail(email.trim())) {
+    Alert.alert("Validation Error", "Please enter a valid email address.");
+    return false;
+  }
+  return true;
+}

mobile/src/types/index.ts

@@ -1,8 +1,37 @@
 // Mobile-specific type aliases and extensions not covered by shared types
 
-export type RootStackParamList = {
+import type { NavigatorScreenParams } from "@react-navigation/native";
-  Auth: undefined;
+import type { MainTabParamList } from "../navigation/MainNavigator";
-  Main: undefined;
+
-  BookReader: { bookId: number };
+/** Stack hosted above the bottom tabs once the user is authenticated. */
-  BookDetail: { bookId: number };
+export type AppStackParamList = {
-};
+  Tabs: NavigatorScreenParams<MainTabParamList> | undefined;
+  BookDetail: { ebookId: number };
+  Reader: { ebookId: number };
+};
+
+/** EPUB bookmark/highlight, mirrors frontend/src/types Bookmark. */
+export interface Bookmark {
+  id: string;
+  ebook: number;
+  ebook_title: string;
+  epub_cfi: string;
+  chapter_index: number;
+  chapter_title: string;
+  page: number;
+  location_text: string;
+  content: string;
+  highlight_color?: string;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface CreateMarkerPayload {
+  ebook: number;
+  epub_cfi: string;
+  chapter_index: number;
+  chapter_title?: string;
+  location_text?: string;
+  content?: string;
+  highlight_color?: string;
+}

mobile/src/types/reader.ts

@@ -0,0 +1,32 @@
+/**
+ * Reader module types for the mobile app. Mirrors
+ * frontend/src/types/reader.ts so settings and progress behave the same
+ * way across web and mobile.
+ */
+
+export interface ReadingSettings {
+  font_family: "sans-serif" | "serif" | "monospace";
+  font_size: number;
+  line_height: number;
+  margin_width: number;
+  background_color: string;
+  text_color: string;
+  brightness: number;
+  orientation_lock: "auto" | "portrait" | "landscape";
+  theme: "sepia" | "dark" | "light" | "paper";
+  created_at: string;
+  updated_at: string;
+}
+
+export type ThemePreset = ReadingSettings["theme"];
+export type FontFamily = ReadingSettings["font_family"];
+
+export interface ReadingProgress {
+  id: number;
+  book: number;
+  current_chapter: number;
+  current_position: number;
+  percentage: number;
+  epub_location: string;
+  updated_at: string;
+}

mobile/src/utils/epubTheme.ts

@@ -0,0 +1,66 @@
+import type { ReadingSettings, ThemePreset } from "../types/reader";
+
+/** CSS font stacks per family, mirrors frontend/src/utils/epubRendition.ts. */
+export const FONT_STACKS: Record<ReadingSettings["font_family"], string> = {
+  serif: 'Georgia, "Times New Roman", serif',
+  "sans-serif":
+    'system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif',
+  monospace: 'ui-monospace, "Cascadia Code", monospace',
+};
+
+/** Background/text/chrome colors for each reader theme preset. */
+export const THEME_PALETTES: Record<
+  ThemePreset,
+  { background: string; text: string; chrome: string }
+> = {
+  light: { background: "#ffffff", text: "#1a1a1a", chrome: "#f2f2f2" },
+  dark: { background: "#121212", text: "#e0e0e0", chrome: "#1c1c1e" },
+  sepia: { background: "#f4ecd8", text: "#5b4636", chrome: "#e8ddc4" },
+  paper: { background: "#fbfbf8", text: "#2b2b2b", chrome: "#efefe9" },
+};
+
+export function resolvePalette(settings: ReadingSettings) {
+  const preset = THEME_PALETTES[settings.theme] ?? THEME_PALETTES.light;
+  return {
+    background: settings.background_color || preset.background,
+    text: settings.text_color || preset.text,
+    chrome: preset.chrome,
+  };
+}
+
+/**
+ * Build an epub.js theme object (selector -> CSS rules) from reader settings.
+ * Used with the epubjs-react-native `changeTheme` method.
+ */
+export function buildEpubTheme(
+  settings: ReadingSettings,
+): Record<string, Record<string, string>> {
+  const { background, text } = resolvePalette(settings);
+  const fontStack = FONT_STACKS[settings.font_family] ?? FONT_STACKS.serif;
+  const lineHeight = `${settings.line_height} !important`;
+  const fontFamily = `${fontStack} !important`;
+  const color = `${text} !important`;
+
+  return {
+    body: {
+      background: `${background} !important`,
+      color,
+      "font-family": fontFamily,
+      "line-height": lineHeight,
+    },
+    p: {
+      color,
+      "font-family": fontFamily,
+      "line-height": lineHeight,
+    },
+    li: { color, "font-family": fontFamily, "line-height": lineHeight },
+    span: { color },
+    a: { color },
+    h1: { color },
+    h2: { color },
+    h3: { color },
+    h4: { color },
+    h5: { color },
+    h6: { color },
+  };
+}

mobile/tsconfig.json

@@ -12,7 +12,8 @@
     "forceConsistentCasingInFileNames": true,
     "baseUrl": ".",
     "paths": {
-      "@/*": ["src/*"]
+      "@/*": ["src/*"],
+      "@cloud-reader/shared": ["../packages/shared/src/index.ts"]
     }
   },
   "include": ["**/*.ts", "**/*.tsx"],

packages/shared/src/types.ts

@@ -215,4 +215,36 @@ export interface PaginatedResponse<T> {
 export interface ApiError {
   detail?: string;
   [key: string]: unknown;
+}
+
+// ---- Reading Groups ----
+
+export interface ReadingGroupSummary {
+  id: number;
+  name: string;
+  ebook: number;
+  ebook_title: string;
+  ebook_author: string;
+  created_by_email: string;
+  description: string;
+  member_count: number;
+  my_progress: {
+    current_section: number;
+    percentage: number;
+    time_spent_seconds: number;
+    section_label: string;
+  } | null;
+  created_at: string;
+  updated_at: string;
+}
+
+export interface MemberProgressPublic {
+  user_id: number;
+  user_email: string;
+  current_section: number;
+  total_sections: number;
+  section_label: string;
+  percentage: number;
+  time_spent_seconds: number;
+  updated_at: string;
 }

packages/shared/src/utils.ts

@@ -114,4 +114,13 @@ export const API_ENDPOINTS = {
     bookmarkDetail: (id: string) => `/api/annotations/bookmarks/${id}/`,
     noteDetail: (id: string) => `/api/annotations/notes/${id}/`,
   },
+  groups: {
+    list: "/api/groups/",
+    detail: (id: number) => `/api/groups/${id}/`,
+    membersProgress: (id: number) => `/api/groups/${id}/members/progress/`,
+    myProgress: (id: number) => `/api/groups/${id}/progress/`,
+    progressSummary: (id: number) => `/api/groups/${id}/progress/summary/`,
+    join: (id: number) => `/api/groups/${id}/join/`,
+    leave: (id: number) => `/api/groups/${id}/leave/`,
+  },
 } as const;