frontend/src/components/reader/BookmarkIcon.tsx

@@ -0,0 +1,26 @@
+/** Same bookmark ribbon as ReaderToolbar, for rail markers (use with rotate for horizontal). */
+
+interface BookmarkIconProps {
+  size?: number;
+  color: string;
+  className?: string;
+}
+
+export function BookmarkIcon({ size = 24, color, className }: BookmarkIconProps) {
+  return (
+    <svg
+      className={className}
+      width={size}
+      height={size}
+      viewBox="0 0 24 24"
+      fill={color}
+      stroke="rgba(255, 255, 255, 0.9)"
+      strokeWidth="1.25"
+      strokeLinecap="round"
+      strokeLinejoin="round"
+      aria-hidden
+    >
+      <path d="M19 21l-7-5-7 5V5a2 2 0 0 1 2-2h10a2 2 0 0 1 2 2z" />
+    </svg>
+  );
+}

frontend/src/components/reader/BookmarkReaderRail.tsx

@@ -0,0 +1,73 @@
+import { useState } from "react";
+import { useTranslation } from "react-i18n-lite";
+import type { BookmarkRailItem } from "@/utils/bookmarkRailLayout";
+import { truncateRailPreview } from "@/utils/bookmarkRailLayout";
+import { normalizeHighlightColor } from "@/constants/bookmarkHighlightColors";
+import { BookmarkIcon } from "./BookmarkIcon";
+
+interface BookmarkReaderRailProps {
+  items: BookmarkRailItem[];
+  onGoToBookmark: (epubCfi: string) => void;
+}
+
+function RailMarker({
+  item,
+  onGoToBookmark,
+}: {
+  item: BookmarkRailItem;
+  onGoToBookmark: (epubCfi: string) => void;
+}) {
+  const { t } = useTranslation();
+  const [hovered, setHovered] = useState(false);
+  const color = normalizeHighlightColor(item.marker.highlight_color);
+  const previewText = truncateRailPreview(item.marker.location_text || "");
+  const notePreview = item.marker.content
+    ? truncateRailPreview(item.marker.content, 80)
+    : "";
+
+  const ariaLabel = previewText
+    ? t("reader.bookmarkRailPreview", { text: previewText })
+    : t("reader.bookmarkRailGoTo");
+
+  return (
+    <li className="reader-bookmark-marker-wrap">
+      <button
+        type="button"
+        className="reader-bookmark-marker"
+        onClick={() => onGoToBookmark(item.marker.epub_cfi)}
+        onMouseEnter={() => setHovered(true)}
+        onMouseLeave={() => setHovered(false)}
+        onFocus={() => setHovered(true)}
+        onBlur={() => setHovered(false)}
+        aria-label={ariaLabel}
+        title={previewText || undefined}
+      >
+        <BookmarkIcon size={28} color={color} className="reader-bookmark-marker-icon" />
+      </button>
+      {hovered && previewText && (
+        <div
+          className="reader-bookmark-preview"
+          style={{ borderLeftColor: color }}
+          role="tooltip"
+        >
+          <p className="reader-bookmark-preview-passage">{previewText}</p>
+          {notePreview && (
+            <p className="reader-bookmark-preview-note">{notePreview}</p>
+          )}
+        </div>
+      )}
+    </li>
+  );
+}
+
+export function BookmarkReaderRail({ items, onGoToBookmark }: BookmarkReaderRailProps) {
+  if (items.length === 0) return null;
+
+  return (
+    <ul className="reader-bookmark-strip" aria-label="Bookmarks">
+      {items.map((item) => (
+        <RailMarker key={item.marker.id} item={item} onGoToBookmark={onGoToBookmark} />
+      ))}
+    </ul>
+  );
+}

frontend/src/hooks/useBookmarkRailLayout.ts

@@ -0,0 +1,7 @@
+import { useMemo } from "react";
+import type { MarkerEntry } from "@/types";
+import { layoutBookmarkRail, type BookmarkRailItem } from "@/utils/bookmarkRailLayout";
+
+export function useBookmarkRailLayout(markers: MarkerEntry[]): BookmarkRailItem[] {
+  return useMemo(() => layoutBookmarkRail(markers), [markers]);
+}

frontend/src/hooks/useEpubReader.ts

@@ -10,6 +10,7 @@ import {
   applyRenditionSettings,
   isEpubCfi,
   marginWidthToGap,
+  percentageFromCfi,
   resolveSpineHref,
   updateChapterTitleFromRendition,
   type EpubRendition,
@@ -28,13 +29,6 @@ export interface ReadingAnchor {
   percentage: number;
 }
 
-function percentageFromCfi(rendition: EpubRendition, cfi: string): number {
-  if (!rendition.book?.locations) return 0;
-  const pct = rendition.book.locations.percentageFromCfi(cfi);
-  if (pct === null || pct === undefined) return 0;
-  return Math.round(pct * 100);
-}
-
 function cfiFromRendition(rendition: EpubRendition | null): string | null {
   if (!rendition) return null;
   const start = (rendition as EpubRendition & { location?: { start?: { cfi?: string } } }).location
@@ -157,7 +151,7 @@ export function useEpubReader(
       cfi = cfiFromRendition(rendition);
     }
     if (!cfi) return null;
-    const percentage = rendition ? percentageFromCfi(rendition, cfi) : 0;
+    const percentage = rendition ? (percentageFromCfi(rendition, cfi) ?? 0) : 0;
     return { cfi, percentage };
   }, [location]);
 
@@ -187,7 +181,7 @@ export function useEpubReader(
 
     setLocation(anchor.cfi);
     const rendition = renditionRef.current;
-    const pct = rendition ? percentageFromCfi(rendition, anchor.cfi) : anchor.percentage;
+    const pct = rendition ? (percentageFromCfi(rendition, anchor.cfi) ?? anchor.percentage) : anchor.percentage;
     void flushProgress(anchor.cfi, pct > 0 ? pct : anchor.percentage);
   }, [clearPeekState, flushProgress]);
 
@@ -267,7 +261,7 @@ export function useEpubReader(
       if (!isEpubCfi(loc)) return;
 
       const rendition = renditionRef.current;
-      const percentage = rendition ? percentageFromCfi(rendition, loc) : 0;
+      const percentage = rendition ? (percentageFromCfi(rendition, loc) ?? 0) : 0;
 
       if (rendition) {
         void updateChapterTitleFromRendition(rendition).then((title) => {
@@ -306,7 +300,7 @@ export function useEpubReader(
       const cfi = start?.cfi;
       if (!cfi || !isEpubCfi(cfi)) return;
 
-      const percentage = percentageFromCfi(rendition, cfi);
+      const percentage = percentageFromCfi(rendition, cfi) ?? 0;
       void flushProgress(cfi, percentage);
 
       if (percentage <= 0 && attempt < 2) {

frontend/src/locales/en-US.ts

@@ -123,6 +123,8 @@ const enUS = {
     nextPage: "Next page",
     resumeReading: "Back to reading",
     resumeReadingAria: "Return to where you were reading",
+    bookmarkRailGoTo: "Go to bookmark",
+    bookmarkRailPreview: "Bookmark: {{text}}",
     backToLibraryAria: "Back to library",
     tocAria: "Table of contents",
     settingsAria: "Reading settings",

frontend/src/locales/es-ES.ts

@@ -125,6 +125,8 @@ const esES: Locale = {
     nextPage: "Página siguiente",
     resumeReading: "Volver a la lectura",
     resumeReadingAria: "Volver a donde estabas leyendo",
+    bookmarkRailGoTo: "Ir al marcador",
+    bookmarkRailPreview: "Marcador: {{text}}",
     backToLibraryAria: "Volver a la biblioteca",
     tocAria: "Tabla de contenidos",
     settingsAria: "Ajustes de lectura",

frontend/src/pages/ReadingPage.tsx

@@ -2,11 +2,13 @@
  * ReadingPage — full-screen EPUB reading view powered by react-reader (epub.js).
  */
 
-import { lazy, Suspense, useCallback, useEffect, useState } from "react";
+import { lazy, Suspense, useCallback, useEffect, useMemo, useState } from "react";
 import { useLocation, useNavigate, useParams } from "react-router-dom";
 import { useTranslation } from "react-i18n-lite";
 import { EpubView, EpubViewStyle } from "react-reader";
 import { booksApi } from "../api/books";
+import { useAnnotations } from "@/context/AnnotationsContext";
+import { useBookmarkRailLayout } from "../hooks/useBookmarkRailLayout";
 import { useEpubHighlights } from "../hooks/useEpubHighlights";
 import { useEpubReader } from "../hooks/useEpubReader";
 import { useEpubSelection } from "../hooks/useEpubSelection";
@@ -15,6 +17,7 @@ import type { EBookDetail } from "../types/book";
 import type { EpubTocItem } from "../components/reader/TableOfContents";
 import { SelectionPopover } from "../components/reader/SelectionPopover";
 import { BookMarkersPanel } from "../components/reader/BookMarkersPanel";
+import { BookmarkReaderRail } from "../components/reader/BookmarkReaderRail";
 import { ResumeReadingButton } from "../components/reader/ResumeReadingButton";
 import type { MarkerEntry } from "@/types";
 import "../reader.css";
@@ -73,7 +76,14 @@ export default function ReadingPage() {
     renditionVersion,
   );
 
+  const { markers } = useAnnotations();
+  const bookMarkers = useMemo(
+    () => markers.filter((m) => m.ebook_id === bookId),
+    [markers, bookId],
+  );
+
   useEpubHighlights(bookId, renditionRef, renditionVersion);
+  const railItems = useBookmarkRailLayout(bookMarkers);
 
   useEffect(() => {
     if (!bookId || Number.isNaN(bookId)) return;
@@ -227,6 +237,10 @@ export default function ReadingPage() {
               </div>
             }
           />
+          <BookmarkReaderRail
+            items={railItems}
+            onGoToBookmark={beginBookmarkPeek}
+          />
           <button
             type="button"
             className="reader-page-nav reader-page-nav--prev"

frontend/src/reader.css

@@ -215,6 +215,105 @@
   display: block;
 }
 
+.reader-bookmark-strip {
+  position: absolute;
+  top: 8px;
+  right: 52px;
+  z-index: 9;
+  display: flex;
+  flex-direction: column;
+  align-items: flex-end;
+  gap: 4px;
+  max-height: min(45vh, 360px);
+  overflow-y: auto;
+  overflow-x: visible;
+  margin: 0;
+  padding: 0;
+  list-style: none;
+  pointer-events: none;
+}
+
+.reader-bookmark-marker-wrap {
+  position: relative;
+  flex-shrink: 0;
+  pointer-events: auto;
+}
+
+.reader-bookmark-marker {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 2px 4px;
+  border: none;
+  background: transparent;
+  cursor: pointer;
+  opacity: 0.55;
+  filter: drop-shadow(0 1px 2px rgba(0, 0, 0, 0.15));
+  transition: opacity 0.15s ease, transform 0.15s ease;
+}
+
+.reader-bookmark-marker-icon {
+  transform: rotate(-90deg);
+  display: block;
+}
+
+.reader-bookmark-marker:hover,
+.reader-bookmark-marker:focus {
+  opacity: 1;
+  transform: scale(1.15);
+  outline: none;
+}
+
+.reader-bookmark-preview {
+  position: absolute;
+  right: calc(100% + 10px);
+  top: 50%;
+  transform: translateY(-50%);
+  width: max-content;
+  max-width: 220px;
+  padding: 8px 10px;
+  background: #fff;
+  border-left: 4px solid #fde047;
+  border-radius: 8px;
+  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
+  z-index: 20;
+  pointer-events: none;
+}
+
+.reader-bookmark-preview-passage {
+  margin: 0;
+  font-size: 0.75rem;
+  line-height: 1.4;
+  color: #374151;
+  font-style: italic;
+}
+
+.reader-bookmark-preview-note {
+  margin: 6px 0 0;
+  font-size: 0.6875rem;
+  line-height: 1.35;
+  color: #6b7280;
+}
+
+.reader-container[data-theme="dark"] .reader-bookmark-preview {
+  background: #2a2a2a;
+  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.4);
+}
+
+.reader-container[data-theme="dark"] .reader-bookmark-preview-passage {
+  color: #e5e7eb;
+}
+
+.reader-container[data-theme="dark"] .reader-bookmark-preview-note {
+  color: #9ca3af;
+}
+
+@media (max-width: 640px) {
+  .reader-bookmark-strip {
+    display: none;
+  }
+}
+
 .reader-container[data-theme="dark"] .reader-page-nav {
   color: rgba(102, 102, 102, 0.9);
 }

frontend/src/utils/bookmarkRailLayout.ts

@@ -0,0 +1,17 @@
+import type { MarkerEntry } from "@/types";
+
+export interface BookmarkRailItem {
+  marker: MarkerEntry;
+}
+
+export function layoutBookmarkRail(markers: MarkerEntry[]): BookmarkRailItem[] {
+  return [...markers]
+    .sort((a, b) => new Date(a.created_at).getTime() - new Date(b.created_at).getTime())
+    .map((marker) => ({ marker }));
+}
+
+export function truncateRailPreview(text: string, max = 120): string {
+  const t = text.trim();
+  if (t.length <= max) return t;
+  return `${t.slice(0, max)}…`;
+}

frontend/src/utils/epubRendition.ts

@@ -55,6 +55,23 @@ export function isEpubCfi(location: string | number): boolean {
   return typeof location === "string" && location.startsWith("epubcfi(");
 }
 
+/** Book progress 0–100 from an EPUB CFI (requires locations.generate). */
+export function percentageFromCfi(rendition: EpubRendition, cfi: string): number | null {
+  if (!rendition.book?.locations || !isEpubCfi(cfi)) return null;
+  try {
+    const pct = rendition.book.locations.percentageFromCfi(cfi);
+    if (pct === null || pct === undefined) return null;
+    return Math.min(100, Math.max(0, Math.round(pct * 100)));
+  } catch {
+    return null;
+  }
+}
+
+export function spineLength(rendition: EpubRendition): number {
+  const items = rendition.book?.spine?.spineItems;
+  return items?.length ?? 0;
+}
+
 /** Map nav/TOC href to a spine href epub.js can display. */
 export function resolveSpineHref(book: EpubBookForNav, href: string): string {
   const hashIndex = href.indexOf("#");