chore(release): v0.1.13

NSSpellChecker's implicit URL handling is unreliable for URLs alone on a
line (a bookmark list), flagging the whole URL as one misspelling. Request
the link checking type alongside spelling so the data detector claims URL
ranges, then keep only spelling results. Real misspellings are unaffected.

package.json

@@ -1,7 +1,7 @@
 {
   "name": "margin-app",
   "private": true,
-  "version": "0.1.11",
+  "version": "0.1.13",
   "type": "module",
   "scripts": {
     "dev": "vite",

src-tauri/Cargo.lock

@@ -4713,11 +4713,14 @@ checksum = "3e2e65a1a2e43cfcb47a895c4c8b10d1f4a61097f9f254f183aee60cad9c651d"
 
 [[package]]
 name = "margin-app"
-version = "0.1.7"
+version = "0.1.11"
 dependencies = [
  "base64 0.22.1",
  "fontdb",
  "harper-core",
+ "objc2",
+ "objc2-app-kit",
+ "objc2-foundation",
  "rand 0.8.6",
  "reqwest 0.12.28",
  "serde",
@@ -5138,9 +5141,17 @@ checksum = "d49e936b501e5c5bf01fda3a9452ff86dc3ea98ad5f283e1455153142d97518c"
 dependencies = [
  "bitflags 2.13.0",
  "block2",
+ "libc",
  "objc2",
+ "objc2-cloud-kit",
+ "objc2-core-data",
  "objc2-core-foundation",
+ "objc2-core-graphics",
+ "objc2-core-image",
+ "objc2-core-text",
+ "objc2-core-video",
  "objc2-foundation",
+ "objc2-quartz-core",
 ]
 
 [[package]]
@@ -5160,6 +5171,7 @@ version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "0b402a653efbb5e82ce4df10683b6b28027616a2715e90009947d50b8dd298fa"
 dependencies = [
+ "bitflags 2.13.0",
  "objc2",
  "objc2-foundation",
 ]
@@ -5220,6 +5232,19 @@ dependencies = [
  "objc2-core-graphics",
 ]
 
+[[package]]
+name = "objc2-core-video"
+version = "0.3.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d425caf1df73233f29fd8a5c3e5edbc30d2d4307870f802d18f00d83dc5141a6"
+dependencies = [
+ "bitflags 2.13.0",
+ "objc2",
+ "objc2-core-foundation",
+ "objc2-core-graphics",
+ "objc2-io-surface",
+]
+
 [[package]]
 name = "objc2-encode"
 version = "4.1.0"

src-tauri/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "margin-app"
-version = "0.1.11"
+version = "0.1.13"
 description = "A Tauri App"
 authors = ["you"]
 edition = "2021"
@@ -31,7 +31,6 @@ fontdb = "0.23"
 typst = "0.14.2"
 typst-pdf = "0.14.2"
 typst-as-lib = "0.15.5"
-spellbook = "0.4"
 # Pinned exactly: the [patch] stubs below are tied to this version's burn/cubecl graph. A minor
 # bump could silently invalidate the patch ("unused") and pull the broken CUDA subtree back in,
 # so bump deliberately and re-audit the stubs. (see [patch.crates-io])
@@ -41,6 +40,18 @@ sha2 = "0.10"
 rand = "0.8"
 url = "2"
 
+# Spelling on macOS uses the system NSSpellChecker (same engine as TextEdit/Safari): far better
+# vocabulary than the bundled Hunspell dictionary and it skips URLs. These objc2 crates are already
+# in the graph via Tauri, so this adds nothing new to the build.
+[target.'cfg(target_os = "macos")'.dependencies]
+objc2 = "0.6"
+objc2-app-kit = { version = "0.3", features = ["NSSpellChecker"] }
+objc2-foundation = { version = "0.3", features = ["NSString", "NSArray", "NSRange", "NSTextCheckingResult"] }
+
+# Other platforms fall back to the bundled Hunspell dictionary via spellbook.
+[target.'cfg(not(target_os = "macos"))'.dependencies]
+spellbook = "0.4"
+
 # harper-core transitively declares an optional, disabled `burn-cuda` (CUDA backend).
 # Cargo still version-resolves that dead subtree, which currently fails (broken tracel-llvm
 # prereleases) and links-collides with `zip`'s lzma. Replace it with an empty stub so the

src-tauri/src/lib.rs

@@ -2,6 +2,8 @@ mod epub;
 mod fonts;
 mod gdrive;
 mod library;
+#[cfg(target_os = "macos")]
+mod macspell;
 mod pdf;
 mod project;
 mod proofing;

src-tauri/src/macspell.rs

@@ -0,0 +1,73 @@
+use std::collections::HashSet;
+
+use objc2::rc::autoreleasepool;
+use objc2_app_kit::NSSpellChecker;
+use objc2_foundation::{NSRange, NSString, NSTextCheckingType};
+
+pub struct MacIssue {
+    pub start: usize,
+    pub end: usize,
+    pub word: String,
+    pub suggestions: Vec<String>,
+}
+
+fn utf16_to_codepoint(text: &str, utf16_len: usize) -> Vec<usize> {
+    let mut map = Vec::with_capacity(utf16_len + 1);
+    let mut cp = 0;
+    for ch in text.chars() {
+        for _ in 0..ch.len_utf16() {
+            map.push(cp);
+        }
+        cp += 1;
+    }
+    map.push(cp);
+    map
+}
+
+pub fn check(text: &str, custom: &HashSet<String>) -> Vec<MacIssue> {
+    autoreleasepool(|_| {
+        let checker = NSSpellChecker::sharedSpellChecker();
+        let ns = NSString::from_str(text);
+        let len = ns.length();
+        let results = unsafe {
+            checker.checkString_range_types_options_inSpellDocumentWithTag_orthography_wordCount(
+                &ns,
+                NSRange { location: 0, length: len },
+                (NSTextCheckingType::Spelling | NSTextCheckingType::Link).bits(),
+                None,
+                0,
+                None,
+                std::ptr::null_mut(),
+            )
+        };
+
+        let map = utf16_to_codepoint(text, len);
+        let chars: Vec<char> = text.chars().collect();
+        let mut issues = Vec::new();
+        for result in results.iter() {
+            if result.resultType() != NSTextCheckingType::Spelling {
+                continue;
+            }
+            let range = result.range();
+            let start = map[range.location.min(len)];
+            let end = map[(range.location + range.length).min(len)];
+            let word: String = chars[start..end].iter().collect();
+            if custom.contains(&word.to_lowercase()) {
+                continue;
+            }
+            let mut suggestions = Vec::new();
+            if let Some(guesses) =
+                checker.guessesForWordRange_inString_language_inSpellDocumentWithTag(range, &ns, None, 0)
+            {
+                for guess in guesses.iter() {
+                    suggestions.push(guess.to_string());
+                    if suggestions.len() >= 5 {
+                        break;
+                    }
+                }
+            }
+            issues.push(MacIssue { start, end, word, suggestions });
+        }
+        issues
+    })
+}

src-tauri/src/proofing.rs

@@ -27,6 +27,7 @@ struct Harper {
 }
 
 pub struct Engine {
+    #[cfg(not(target_os = "macos"))]
     speller: Option<spellbook::Dictionary>,
     harper: Option<Harper>,
     custom: HashSet<String>,
@@ -87,6 +88,7 @@ fn load_custom(app: &tauri::AppHandle) -> HashSet<String> {
     set
 }
 
+#[cfg(not(target_os = "macos"))]
 fn build_speller(app: &tauri::AppHandle) -> Result<spellbook::Dictionary, String> {
     let aff = dict_file(app, "index.aff")?;
     let dic = dict_file(app, "index.dic")?;
@@ -100,18 +102,22 @@ fn build_harper() -> Harper {
     Harper { linter, dict }
 }
 
+#[cfg(not(target_os = "macos"))]
 fn is_word_char(c: char) -> bool {
     c.is_alphabetic()
 }
 
+#[cfg(not(target_os = "macos"))]
 fn has_irregular_case(word: &str) -> bool {
     word.chars().skip(1).any(|c| c.is_uppercase())
 }
 
+#[cfg(not(target_os = "macos"))]
 fn is_apostrophe(c: char) -> bool {
     c == '\'' || c == '\u{2019}'
 }
 
+#[cfg(not(target_os = "macos"))]
 fn collect_spelling(
     speller: &spellbook::Dictionary,
     custom: &HashSet<String>,
@@ -143,6 +149,10 @@ fn collect_spelling(
         }
         let mut suggestions = Vec::new();
         speller.suggest(&word, &mut suggestions);
+        let lower = word.to_lowercase();
+        if suggestions.iter().any(|s| s.to_lowercase() == lower) {
+            continue;
+        }
         suggestions.truncate(5);
         issues.push(Issue {
             start,
@@ -197,6 +207,7 @@ pub async fn proof_text(
             let mut custom = load_custom(&app);
             load_tech(&app, &mut custom);
             *guard = Some(Engine {
+                #[cfg(not(target_os = "macos"))]
                 speller: None,
                 harper: None,
                 custom,
@@ -207,11 +218,25 @@ pub async fn proof_text(
         let chars: Vec<char> = text.chars().collect();
         let mut issues = Vec::new();
         if spelling {
+            #[cfg(target_os = "macos")]
+            for mi in crate::macspell::check(&text, &engine.custom) {
+                issues.push(Issue {
+                    start: mi.start,
+                    end: mi.end,
+                    kind: "spelling".into(),
+                    category: "Spelling".into(),
+                    message: format!("“{}” may be misspelled", mi.word),
+                    suggestions: mi.suggestions,
+                });
+            }
+            #[cfg(not(target_os = "macos"))]
+            {
                 if engine.speller.is_none() {
                     engine.speller = Some(build_speller(&app)?);
                 }
                 collect_spelling(engine.speller.as_ref().unwrap(), &engine.custom, &chars, &mut issues);
             }
+        }
         if grammar {
             if engine.harper.is_none() {
                 engine.harper = Some(build_harper());

src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "Margin",
-  "version": "0.1.11",
+  "version": "0.1.13",
   "identifier": "studio.margin.app",
   "build": {
     "beforeDevCommand": "pnpm dev",

src/components/AddPageMenu.tsx

@@ -16,6 +16,7 @@ export function AddPageMenu({ onAdd, onAddPart }: AddPageMenuProps) {
   const [open, setOpen] = useState(false);
   const [coords, setCoords] = useState({ top: 0, left: 0 });
   const btnRef = useRef<HTMLButtonElement>(null);
+  const popRef = useRef<HTMLDivElement>(null);
 
   const toggle = () => {
     if (!open && btnRef.current) {
@@ -38,6 +39,25 @@ export function AddPageMenu({ onAdd, onAddPart }: AddPageMenuProps) {
     };
   }, [open]);
 
+  useEffect(() => {
+    if (!open) return;
+    popRef.current?.querySelector<HTMLElement>(".add-page-item")?.focus();
+  }, [open]);
+
+  const onMenuKeyDown = (e: React.KeyboardEvent) => {
+    if (e.key === "Escape") {
+      e.preventDefault();
+      setOpen(false);
+      btnRef.current?.focus();
+    } else if (e.key === "ArrowDown" || e.key === "ArrowUp") {
+      e.preventDefault();
+      const items = Array.from(popRef.current?.querySelectorAll<HTMLElement>(".add-page-item") ?? []);
+      const idx = items.indexOf(document.activeElement as HTMLElement);
+      const nextIdx = e.key === "ArrowDown" ? (idx + 1) % items.length : (idx - 1 + items.length) % items.length;
+      items[nextIdx]?.focus();
+    }
+  };
+
   const pick = (group: "front" | "back", label: string) => {
     setOpen(false);
     onAdd(group, label);
@@ -56,9 +76,11 @@ export function AddPageMenu({ onAdd, onAddPart }: AddPageMenuProps) {
       </button>
       {open && (
         <div
+          ref={popRef}
           className="add-page-pop"
           style={{ top: coords.top, left: coords.left }}
           onMouseDown={(e) => e.stopPropagation()}
+          onKeyDown={onMenuKeyDown}
         >
           <div className="add-page-group">
             <div className="add-page-label">Body</div>

src/components/ConfirmDialog.tsx

@@ -1,4 +1,4 @@
-import type { ReactNode } from "react";
+import { useEffect, useRef, type ReactNode } from "react";
 import { Icon } from "./Icon";
 
 interface ConfirmDialogProps {
@@ -10,6 +10,21 @@ interface ConfirmDialogProps {
 }
 
 export function ConfirmDialog({ title, message, confirmLabel = "Delete", onConfirm, onClose }: ConfirmDialogProps) {
+  const confirmRef = useRef<HTMLButtonElement>(null);
+
+  useEffect(() => {
+    confirmRef.current?.focus();
+    const onKey = (e: KeyboardEvent) => {
+      if (e.key === "Escape") {
+        e.preventDefault();
+        onClose();
+      }
+    };
+    window.addEventListener("keydown", onKey);
+    return () => window.removeEventListener("keydown", onKey);
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, []);
+
   return (
     <div className="overlay" onClick={onClose}>
       <div className="panel panel-confirm" onClick={(e) => e.stopPropagation()}>
@@ -26,7 +41,7 @@ export function ConfirmDialog({ title, message, confirmLabel = "Delete", onConfi
           <button className="btn-ghost" onClick={onClose}>
             Cancel
           </button>
-          <button className="btn-danger" onClick={onConfirm}>
+          <button ref={confirmRef} className="btn-danger" onClick={onConfirm}>
             {confirmLabel}
           </button>
         </div>

src/components/EditorView.tsx

@@ -44,6 +44,9 @@ export function EditorView() {
 
   const isCompact = useCompact();
   const [editor, setEditor] = useState<TiptapEditor | null>(null);
+  const editorRef = useRef<TiptapEditor | null>(null);
+  editorRef.current = editor;
+  const lastChapterRef = useRef<string>("");
   const [sidebarOpen, setSidebarOpen] = useState(!isCompact);
   const [dock, setDock] = useState(!isCompact);
   const [settingsOpen, setSettingsOpen] = useState(false);
@@ -83,6 +86,18 @@ export function EditorView() {
     setFindOpen(true);
   }, []);
 
+  const focusEditorSoon = useCallback(() => {
+    requestAnimationFrame(() => editorRef.current?.commands.focus(undefined, { scrollIntoView: false }));
+  }, []);
+
+  const switchChapter = useCallback(
+    (dir: 1 | -1) => {
+      useBook.getState().goToAdjacentChapter(dir);
+      focusEditorSoon();
+    },
+    [focusEditorSoon]
+  );
+
   const reproof = useCallback(() => {
     if (!editor) return;
     const state = useProofing.getState();
@@ -120,11 +135,36 @@ export function EditorView() {
       } else if ((e.metaKey || e.ctrlKey) && e.key.toLowerCase() === "f") {
         e.preventDefault();
         openFind(e.altKey);
+      } else if (e.metaKey && e.altKey && (e.key === "ArrowDown" || e.key === "ArrowRight")) {
+        e.preventDefault();
+        e.stopPropagation();
+        switchChapter(1);
+      } else if (e.metaKey && e.altKey && (e.key === "ArrowUp" || e.key === "ArrowLeft")) {
+        e.preventDefault();
+        e.stopPropagation();
+        switchChapter(-1);
+      } else if (e.ctrlKey && !e.metaKey && e.key === "Tab") {
+        e.preventDefault();
+        e.stopPropagation();
+        switchChapter(e.shiftKey ? -1 : 1);
+      }
+    };
+    window.addEventListener("keydown", onKey, true);
+    return () => window.removeEventListener("keydown", onKey, true);
+  }, [saveNow, openFind, switchChapter]);
+
+  useEffect(() => {
+    if (!widthOpen && !exportOpen && !moreOpen) return;
+    const onKey = (e: KeyboardEvent) => {
+      if (e.key === "Escape") {
+        setWidthOpen(false);
+        setExportOpen(false);
+        setMoreOpen(false);
       }
     };
     window.addEventListener("keydown", onKey);
     return () => window.removeEventListener("keydown", onKey);
-  }, [saveNow, openFind]);
+  }, [widthOpen, exportOpen, moreOpen]);
 
   useEffect(() => {
     if (!notice) return;
@@ -177,8 +217,11 @@ export function EditorView() {
   };
 
   if (!book) return null;
-  const idx = book.chapters.findIndex((c) => c.id === activeChapterId);
+  const activeIdx = book.chapters.findIndex((c) => c.id === activeChapterId);
-  const chapter = book.chapters[idx] ?? book.chapters[0];
+  const activeChapter = book.chapters[activeIdx];
+  if (activeChapter) lastChapterRef.current = activeChapter.id;
+  const editorIdx = activeChapter ? activeIdx : book.chapters.findIndex((c) => c.id === lastChapterRef.current);
+  const chapter = book.chapters[editorIdx] ?? book.chapters[0];
   const realIdx = book.chapters.findIndex((c) => c.id === chapter?.id);
   const kind = chapter ? chapterKind(chapter) : "body";
   const eyebrow =
@@ -342,14 +385,16 @@ export function EditorView() {
       />
 
       <div className="body">
-        <Sidebar onNavigate={() => isCompact && setSidebarOpen(false)} />
+        <Sidebar
+          onNavigate={() => {
+            if (isCompact) setSidebarOpen(false);
+            focusEditorSoon();
+          }}
+        />
         {sidebarOpen && !isCompact && <ResizeHandle pane="sidebar" />}
         <main className="editor-pane">
-          {coverActive ? (
+          {coverActive && <CoverView />}
-            <CoverView />
+          <article className="sheet" hidden={coverActive}>
-          ) : (
-            <>
-              <article className="sheet">
             <header className="chapter-opener">
               <div className="chapter-num">{eyebrow}</div>
               <ChapterTitleInput
@@ -372,7 +417,6 @@ export function EditorView() {
               )}
             </header>
             <Editor
-                  key={chapter.id}
               bookId={book.id}
               chapterId={chapter.id}
               content={chapter.content}
@@ -383,9 +427,7 @@ export function EditorView() {
               }
             />
           </article>
-              <FloatingToolbar editor={editor} />
+          {!coverActive && <FloatingToolbar editor={editor} />}
-            </>
-          )}
         </main>
         {dock && !isCompact && <ResizeHandle pane="dock" />}
         {dock && <Dock />}

src/components/FindBar.tsx

@@ -58,7 +58,7 @@ export function FindBar({ editor, open, initialExpanded, onClose }: FindBarProps
     return () => {
       editor.off("transaction", update);
     };
-  }, [editor]);
+  }, [editor, activeChapterId]);
 
   useEffect(() => {
     if (!editor) return;
@@ -67,7 +67,7 @@ export function FindBar({ editor, open, initialExpanded, onClose }: FindBarProps
     } else {
       editor.commands.clearSearch();
     }
-  }, [editor, open, query, caseSensitive, wholeWord]);
+  }, [editor, open, query, caseSensitive, wholeWord, activeChapterId]);
 
   useEffect(() => {
     if (open) {

src/components/Library.tsx

@@ -51,6 +51,11 @@ export function Library({ onOpen }: { onOpen: (book: Book) => void }) {
     onOpen(copy);
   };
 
+  const openById = (id: string) =>
+    loadBook(id)
+      .then(onOpen)
+      .catch((e) => setNotice(`Could not open book: ${e}`));
+
   const removeBook = async () => {
     if (!pendingDelete) return;
     await deleteBook(pendingDelete.id);
@@ -108,7 +113,15 @@ export function Library({ onOpen }: { onOpen: (book: Book) => void }) {
             <div
               key={b.id}
               className="card card-book"
-              onClick={() => loadBook(b.id).then(onOpen).catch((e) => setNotice(`Could not open book: ${e}`))}
+              role="button"
+              tabIndex={0}
+              onClick={() => openById(b.id)}
+              onKeyDown={(e) => {
+                if (e.key === "Enter" || e.key === " ") {
+                  e.preventDefault();
+                  openById(b.id);
+                }
+              }}
             >
               <span className="card-title">{b.title || "Untitled"}</span>
               {b.author && <span className="card-author">{b.author}</span>}

src/components/RowMenu.tsx

@@ -33,6 +33,25 @@ export function RowMenu({ label, onDuplicate, onDelete, onToggleTitle, titleHidd
     setOpen((v) => !v);
   };
 
+  useEffect(() => {
+    if (!open) return;
+    popRef.current?.querySelector<HTMLElement>(".row-menu-item")?.focus();
+  }, [open]);
+
+  const onMenuKeyDown = (e: React.KeyboardEvent) => {
+    if (e.key === "Escape") {
+      e.preventDefault();
+      setOpen(false);
+      btnRef.current?.focus();
+    } else if (e.key === "ArrowDown" || e.key === "ArrowUp") {
+      e.preventDefault();
+      const items = Array.from(popRef.current?.querySelectorAll<HTMLElement>(".row-menu-item") ?? []);
+      const idx = items.indexOf(document.activeElement as HTMLElement);
+      const nextIdx = e.key === "ArrowDown" ? (idx + 1) % items.length : (idx - 1 + items.length) % items.length;
+      items[nextIdx]?.focus();
+    }
+  };
+
   useEffect(() => {
     if (!open) return;
     const onDown = (e: MouseEvent) => {
@@ -88,7 +107,7 @@ export function RowMenu({ label, onDuplicate, onDelete, onToggleTitle, titleHidd
       </button>
       {open &&
         createPortal(
-          <div ref={popRef} className="row-menu-pop" style={{ top: coords.top, right: coords.right }}>
+          <div ref={popRef} className="row-menu-pop" style={{ top: coords.top, right: coords.right }} onKeyDown={onMenuKeyDown}>
             {onToggleTitle && (
               <button className="row-menu-item" onClick={toggleTitle}>
                 {titleHidden ? (

src/components/Settings.tsx

@@ -94,6 +94,17 @@ export function Settings({ onClose, onSave }: { onClose: () => void; onSave: ()
     });
   }, []);
 
+  useEffect(() => {
+    const onKey = (e: KeyboardEvent) => {
+      if (e.key === "Escape") {
+        e.preventDefault();
+        onClose();
+      }
+    };
+    window.addEventListener("keydown", onKey);
+    return () => window.removeEventListener("keydown", onKey);
+  }, [onClose]);
+
   if (!book) return null;
 
   const set = (patch: Partial<Draft>) => setDraft((d) => ({ ...d, ...patch }));
@@ -121,7 +132,7 @@ export function Settings({ onClose, onSave }: { onClose: () => void; onSave: ()
         </div>
         <div className="panel-body">
           <Field label="Title">
-            <input value={draft.title} placeholder="Untitled" onChange={(e) => set({ title: e.target.value })} />
+            <input autoFocus value={draft.title} placeholder="Untitled" onChange={(e) => set({ title: e.target.value })} />
           </Field>
           <Field label="Subtitle">
             <input value={draft.subtitle} onChange={(e) => set({ subtitle: e.target.value })} />

src/components/Sidebar.tsx

@@ -155,6 +155,33 @@ export function Sidebar({ onNavigate }: { onNavigate?: () => void }) {
     onNavigate?.();
   };
 
+  const focusRow = (id: string) =>
+    requestAnimationFrame(() => {
+      document.querySelector<HTMLElement>(`.chapter[data-id="${CSS.escape(id)}"]`)?.focus();
+    });
+
+  const onRowKeyDown = (e: React.KeyboardEvent, index: number, id: string) => {
+    if (e.key === "Enter" || e.key === " ") {
+      e.preventDefault();
+      setActiveChapter(id);
+      onNavigate?.();
+    } else if (e.key === "ArrowDown" || e.key === "ArrowUp" || e.key === "Home" || e.key === "End") {
+      e.preventDefault();
+      const target =
+        e.key === "Home"
+          ? chapters[0]
+          : e.key === "End"
+            ? chapters[chapters.length - 1]
+            : chapters[index + (e.key === "ArrowDown" ? 1 : -1)];
+      if (target) {
+        setActiveChapter(target.id);
+        focusRow(target.id);
+      }
+    }
+  };
+
+  const tabStopId = chapters.some((c) => c.id === activeChapterId) ? activeChapterId : chapters[0]?.id;
+
   return (
     <aside className="sidebar">
       <button className="brand" onClick={closeBook} title="All books">
@@ -193,6 +220,7 @@ export function Sidebar({ onNavigate }: { onNavigate?: () => void }) {
                     key={row.chapter.id}
                     className="chapter"
                     data-idx={row.index}
+                    data-id={row.chapter.id}
                     data-kind={group.kind}
                     data-part={isPart}
                     data-indent={row.indent}
@@ -200,7 +228,11 @@ export function Sidebar({ onNavigate }: { onNavigate?: () => void }) {
                     data-dragging={dragIndex === row.index}
                     data-drop-before={dropTarget?.kind === group.kind && dropTarget.index === row.index}
                     data-drop-after={dropTarget?.kind === group.kind && i === group.rows.length - 1 && dropTarget.index === row.index + 1}
+                    role="button"
+                    tabIndex={row.chapter.id === tabStopId ? 0 : -1}
+                    aria-current={row.chapter.id === activeChapterId}
                     onClick={() => onRowClick(row.chapter.id)}
+                    onKeyDown={(e) => onRowKeyDown(e, row.index, row.chapter.id)}
                     onPointerDown={(e) => onRowPointerDown(e, row.index)}
                   >
                     <span className="grip" title="Drag to reorder">

src/editor/Editor.tsx

@@ -1,8 +1,10 @@
-import { useEffect, useRef } from "react";
+import { useEffect, useLayoutEffect, useRef } from "react";
 import { EditorContent, useEditor, type Editor as TiptapEditor } from "@tiptap/react";
+import { EditorState } from "@tiptap/pm/state";
 import type { JSONContent } from "@tiptap/core";
 import { editorExtensions } from "./extensions";
 import { loadPosition, savePosition, type ChapterPosition } from "./positions";
+import { useBook } from "../store/useBook";
 
 interface EditorProps {
   bookId: string;
@@ -13,13 +15,34 @@ interface EditorProps {
   onContentError: (error: Error) => void;
 }
 
+interface Cached {
+  state: EditorState;
+  content: JSONContent;
+  scroll: number;
+}
+
+function buildState(editor: TiptapEditor, content: JSONContent, onError: (error: Error) => void): EditorState {
+  const base = editor.view.state;
+  try {
+    const doc = editor.schema.nodeFromJSON(content);
+    doc.check();
+    return EditorState.create({ doc, plugins: base.plugins });
+  } catch (error) {
+    onError(error as Error);
+    return EditorState.create({ schema: base.schema, plugins: base.plugins });
+  }
+}
+
 export function Editor({ bookId, chapterId, content, onChange, onReady, onContentError }: EditorProps) {
   const onChangeRef = useRef(onChange);
   onChangeRef.current = onChange;
   const onContentErrorRef = useRef(onContentError);
   onContentErrorRef.current = onContentError;
 
+  const cache = useRef(new Map<string, Cached>());
+  const activeId = useRef(chapterId);
   const latest = useRef<ChapterPosition | null>(null);
+  const restoreToken = useRef(0);
 
   const editor = useEditor({
     extensions: editorExtensions,
@@ -31,49 +54,84 @@ export function Editor({ bookId, chapterId, content, onChange, onReady, onConten
     onUpdate: ({ editor }) => onChangeRef.current(editor.getJSON()),
   });
 
-  useEffect(() => {
+  const scrollerOf = (ed: TiptapEditor) => ed.view.dom.closest(".editor-pane") as HTMLElement | null;
-    onReady(editor);
+
-    return () => onReady(null);
+  const restorePosition = (ed: TiptapEditor, id: string, focus: boolean) => {
-  }, [editor, onReady]);
+    const scroller = scrollerOf(ed);
+    const saved = loadPosition(bookId, id);
+    const size = ed.state.doc.content.size;
+    const selection = saved ? { from: Math.min(saved.from, size), to: Math.min(saved.to, size) } : 0;
+    const chain = ed.chain().setTextSelection(selection);
+    if (focus) chain.focus(undefined, { scrollIntoView: false });
+    chain.run();
+    if (scroller) {
+      const token = ++restoreToken.current;
+      const top = saved?.scroll ?? 0;
+      const apply = () => {
+        if (restoreToken.current === token) scroller.scrollTop = top;
+      };
+      apply();
+      requestAnimationFrame(apply);
+      document.fonts?.ready.then(apply).catch(() => {});
+    }
+  };
+
+  const stash = (ed: TiptapEditor, id: string) => {
+    const scroller = scrollerOf(ed);
+    const { from, to } = ed.state.selection;
+    const scroll = scroller?.scrollTop ?? 0;
+    const stored = useBook.getState().book?.chapters.find((c) => c.id === id)?.content ?? cache.current.get(id)?.content ?? ed.getJSON();
+    cache.current.set(id, { state: ed.view.state, content: stored, scroll });
+    savePosition(bookId, id, { from, to, scroll });
+  };
 
   useEffect(() => {
     if (!editor) return;
-    let active = true;
+    cache.current.set(chapterId, { state: editor.view.state, content, scroll: 0 });
-    const scroller = editor.view.dom.closest(".editor-pane") as HTMLElement | null;
+    activeId.current = chapterId;
-
+    restorePosition(editor, chapterId, true);
-    const saved = loadPosition(bookId, chapterId);
+    onReady(editor);
-    const size = editor.state.doc.content.size;
+    return () => onReady(null);
-    const selection = saved ? { from: Math.min(saved.from, size), to: Math.min(saved.to, size) } : 0;
-    editor.chain().setTextSelection(selection).focus(undefined, { scrollIntoView: false }).run();
-
-    if (scroller) {
-      const top = saved?.scroll ?? 0;
-      const restore = () => {
-        if (active) scroller.scrollTop = top;
-      };
-      restore();
-      requestAnimationFrame(restore);
-      document.fonts?.ready.then(restore).catch(() => {});
-    }
-
-    return () => {
-      active = false;
-    };
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [editor]);
 
+  useLayoutEffect(() => {
+    if (!editor) return;
+    const prev = activeId.current;
+    if (prev === chapterId) return;
+
+    stash(editor, prev);
+    const entry = cache.current.get(chapterId);
+    if (entry && entry.content === content) {
+      editor.view.updateState(entry.state);
+      const scroller = scrollerOf(editor);
+      if (scroller) scroller.scrollTop = entry.scroll;
+      ++restoreToken.current;
+    } else {
+      editor.view.updateState(buildState(editor, content, onContentErrorRef.current));
+      cache.current.set(chapterId, { state: editor.view.state, content, scroll: 0 });
+      restorePosition(editor, chapterId, false);
+    }
+    activeId.current = chapterId;
+    latest.current = null;
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [chapterId, content, editor]);
+
   useEffect(() => {
     if (!editor) return;
-    const scroller = editor.view.dom.closest(".editor-pane") as HTMLElement | null;
+    const scroller = scrollerOf(editor);
     let timer: ReturnType<typeof setTimeout>;
     const capture = () => {
       const { from, to } = editor.state.selection;
-      latest.current = { from, to, scroll: scroller?.scrollTop ?? 0 };
+      const scroll = scroller?.scrollTop ?? 0;
+      latest.current = { from, to, scroll };
+      const entry = cache.current.get(activeId.current);
+      if (entry) entry.scroll = scroll;
     };
     const persist = () => {
       capture();
       clearTimeout(timer);
-      timer = setTimeout(() => savePosition(bookId, chapterId, latest.current!), 400);
+      timer = setTimeout(() => savePosition(bookId, activeId.current, latest.current!), 400);
     };
     editor.on("selectionUpdate", persist);
     scroller?.addEventListener("scroll", persist, { passive: true });
@@ -81,9 +139,9 @@ export function Editor({ bookId, chapterId, content, onChange, onReady, onConten
       clearTimeout(timer);
       editor.off("selectionUpdate", persist);
       scroller?.removeEventListener("scroll", persist);
-      if (latest.current) savePosition(bookId, chapterId, latest.current);
+      if (latest.current) savePosition(bookId, activeId.current, latest.current);
     };
-  }, [editor, bookId, chapterId]);
+  }, [editor, bookId]);
 
   return <EditorContent editor={editor} className="editor-host" />;
 }

src/store/useBook.ts

@@ -30,6 +30,7 @@ interface BookState {
   openBook: (book: Book) => void;
   closeBook: () => void;
   setActiveChapter: (id: string) => void;
+  goToAdjacentChapter: (dir: 1 | -1) => void;
   setChapterContent: (id: string, content: JSONContent) => void;
   setChapterTitle: (id: string, title: string) => void;
   setChapterNoTitle: (id: string, noTitle: boolean) => void;
@@ -73,6 +74,15 @@ export const useBook = create<BookState>((set, get) => ({
     set({ book: null, activeChapterId: "", dirty: false });
   },
   setActiveChapter: (id) => set({ activeChapterId: id }),
+  goToAdjacentChapter: (dir) => {
+    const { book, activeChapterId } = get();
+    if (!book) return;
+    const ids = [COVER_ID, ...book.chapters.map((c) => c.id)];
+    const i = ids.indexOf(activeChapterId);
+    if (i === -1) return;
+    const next = ids[(i + dir + ids.length) % ids.length];
+    if (next !== activeChapterId) set({ activeChapterId: next });
+  },
   setChapterContent: (id, content) =>
     set((s) =>
       s.book

src/styles/app.css

@@ -40,6 +40,22 @@ button {
   padding: 0;
 }
 
+:focus-visible {
+  outline: 2px solid var(--accent);
+  outline-offset: 2px;
+}
+
+.chapter:focus-visible,
+.card:focus-visible {
+  outline-offset: -2px;
+}
+
+.prose:focus,
+.prose:focus-visible,
+.editor-host:focus-visible {
+  outline: none;
+}
+
 .app {
   display: flex;
   flex-direction: column;