feat: add intra-line word-diff highlighting

.claude-plugin/skills/revdiff/references/config.md

@@ -71,7 +71,7 @@ revdiff --dump-theme > ~/.config/revdiff/themes/my-custom  # export current colo
 
 Set default theme in config: `theme = dracula`. Or env: `REVDIFF_THEME=dracula`.
 
-**Custom themes:** customize colors in config or via `--color-*` flags, then `revdiff --dump-theme > ~/.config/revdiff/themes/my-custom`. Or copy a bundled theme file and edit directly — each has all 21 color keys + `chroma-style`.
+**Custom themes:** customize colors in config or via `--color-*` flags, then `revdiff --dump-theme > ~/.config/revdiff/themes/my-custom`. Or copy a bundled theme file and edit directly — each has all 23 color keys + `chroma-style`.
 
 Precedence: `--theme` takes over completely — overwrites all color fields, ignoring `--color-*` flags and env vars. Without `--theme`: built-in defaults → config file → env vars → CLI flags. `--theme` + `--no-colors` prints warning and applies theme.
 
@@ -94,6 +94,8 @@ All color options accept hex values (`#rrggbb`) and have corresponding `REVDIFF_
 | `--color-add-bg` | Added line background | `#123800` |
 | `--color-remove-fg` | Removed line text | `#ff8787` |
 | `--color-remove-bg` | Removed line background | `#4D1100` |
+| `--color-word-add-bg` | Intra-line word-diff add background | auto-derived from add-bg |
+| `--color-word-remove-bg` | Intra-line word-diff remove background | auto-derived from remove-bg |
 | `--color-modify-fg` | Modified line text (collapsed mode) | `#f5c542` |
 | `--color-modify-bg` | Modified line background (collapsed mode) | `#3D2E00` |
 | `--color-tree-bg` | File tree pane background | terminal default |

CLAUDE.md

@@ -26,6 +26,8 @@ TUI for reviewing diffs, files, and documents with inline annotations, built wit
   - `annotlist.go` - annotation list overlay
   - `mdtoc.go` - markdown TOC component
   - `search.go` - search input and navigation
+  - `worddiff.go` - intra-line word-diff: tokenizer, LCS, line pairing, range computation
+  - `colorutil.go` - color utility: HSL conversion, shiftLightness for auto-deriving word-diff bg
   - `styles.go` - lipgloss styles and theme integration
 - `app/highlight/` - chroma-based syntax highlighting, foreground-only ANSI output
 - `app/keymap/` - user-configurable keybindings (`Action` constants, `Keymap` type, parser, defaults, dump)
@@ -44,8 +46,14 @@ git diff → diff.parseUnifiedDiff() → []DiffLine
   (or: disk file → diff.readFileAsContext() → []DiffLine, all ChangeContext)
   (or: stdin / arbitrary reader → diff.readReaderAsContext() → []DiffLine, all ChangeContext)
   → highlight.HighlightLines() → []string (ANSI foreground-only)
+  → recomputeIntraRanges(): pairs add/remove lines within hunks via pairHunkLines(),
+    runs token-level LCS diff (changedTokenRanges) on each pair, stores [][]matchRange
+    parallel to diffLines. 30% similarity gate discards ranges for dissimilar pairs.
+    Ranges are byte offsets on tab-replaced content, aligning with prepareLineContent output.
   → ui.renderDiff() dispatches:
     expanded (default): renderDiffLine() for each line
+      intra-line word-diff: when intraRanges[idx] is non-nil, insertHighlightMarkers()
+      adds WordAddBg/WordRemoveBg ANSI bg markers around changed spans (reverse-video in no-color mode)
     collapsed (`v` toggle): renderCollapsedDiff() → skips removed lines,
       uses buildModifiedSet() to style adds as modify (amber ~) or pure add (green +)
       expanded hunks (`.` toggle) show all lines inline
@@ -62,9 +70,9 @@ git diff → diff.parseUnifiedDiff() → []DiffLine
     wrapContent() splits long lines via ansi.Wrap,
     continuation lines get `↪` gutter marker, cursorViewportY() sums wrapped line counts.
     ansi.Wrap does not preserve SGR state across inserted newlines, so reemitANSIState()
-    re-prepends active fg color, bold, and italic at the start of each continuation line.
+    re-prepends active fg color, bold, italic, and bg at the start of each continuation line.
     State tracking via scanANSIState()/parseSGR()/applySGR(); handles chroma's fg (24-bit/basic),
-    bold (1/22), italic (3/23), fg reset (39), and full reset (0/bare)
+    bold (1/22), italic (3/23), bg (48;2;r;g;b/49), fg reset (39), and full reset (0/bare)
   when search is active (`/` to search, `n`/`N` to navigate, `esc` to clear):
     buildSearchMatchSet() converts match indices to O(1) map per render,
     highlightSearchMatches() inserts ANSI bg-only sequence around matched substrings
@@ -85,7 +93,7 @@ git diff → diff.parseUnifiedDiff() → []DiffLine
 - `no-ini:"true"` tag excludes fields from config file (used for --config, --dump-config, --dump-theme, --list-themes, --init-themes, --version)
 - Themes dir: `~/.config/revdiff/themes/` with 7 bundled themes (revdiff, catppuccin-mocha, catppuccin-latte, dracula, gruvbox, nord, solarized-dark), auto-created on first run
 - `--theme NAME` loads theme; `--dump-theme` exports resolved colors; `--list-themes` lists available; `--init-themes` re-creates bundled
-- Theme precedence: `--theme` takes over completely — overwrites all 21 color fields + chroma-style, ignoring any `--color-*` flags or env vars. `--theme` + `--no-colors` prints warning and applies theme.
+- Theme precedence: `--theme` takes over completely — overwrites all 23 color fields + chroma-style, ignoring any `--color-*` flags or env vars. `--theme` + `--no-colors` prints warning and applies theme.
 - Theme values applied via `applyTheme()` in `main.go` which directly overwrites `opts.Colors.*` fields after `parseArgs()`. `colorFieldPtrs(opts)` is the single source of truth for the color key → struct field mapping, used by both `applyTheme()` and `collectColors()` — adding a new color requires changes in `theme.go` colorKeys + options struct + `colorFieldPtrs()`
 - `ini-name` tags ensure config keys match CLI long flag names
 - Keybindings file: `~/.config/revdiff/keybindings` (`map <key> <action>` / `unmap <key>` format)

README.md

@@ -8,6 +8,7 @@ Built for a specific use case: reviewing code changes, plans, and documents with
 
 - Structured annotation output to stdout - pipe into AI agents, scripts, or other tools
 - Full-file diff view with syntax highlighting
+- Intra-line word-diff: highlights the specific changed words within paired add/remove lines using a brighter background overlay, always on
 - Collapsed diff mode: shows final text with change markers, toggle with `v`
 - Word wrap mode: wraps long lines at viewport boundary with `↪` continuation markers, toggle with `w`
 - Line numbers: side-by-side old/new line number gutter, toggle with `L`
@@ -295,15 +296,15 @@ revdiff --dump-theme > ~/.config/revdiff/themes/my-custom
 **Creating custom themes** — two approaches:
 
 1. **From current colors:** customize individual colors in your config file or via `--color-*` flags, then dump the resolved result as a theme: `revdiff --dump-theme > ~/.config/revdiff/themes/my-custom`
-2. **From scratch:** copy a bundled theme and edit it directly — each file defines all 21 color keys plus `chroma-style` in INI format:
+2. **From scratch:** copy a bundled theme and edit it directly — each file defines all 23 color keys plus `chroma-style` in INI format:
 
 ```ini
 # name: my-custom
 # description: custom color scheme
 chroma-style = dracula
 color-accent = #bd93f9
 color-border = #6272a4
-...all 21 color keys...
+...all 23 color keys...
 ```
 
 Set a default theme in the config file:
@@ -316,7 +317,7 @@ Or via environment variable: `REVDIFF_THEME=dracula`.
 
 **Contributing themes** — community themes live in the `themes/gallery/` directory. See [themes/README.md](themes/README.md) for the contribution guide, format requirements, and validation instructions.
 
-**Precedence:** When `--theme` is set, it takes over completely — all 21 color fields and chroma-style are overwritten by the theme, ignoring any `--color-*` flags or env vars. Without `--theme`: built-in defaults → config file → env vars → CLI flags. `--theme` + `--no-colors` prints a warning and applies the theme.
+**Precedence:** When `--theme` is set, it takes over completely — all 23 color fields and chroma-style are overwritten by the theme, ignoring any `--color-*` flags or env vars. Without `--theme`: built-in defaults → config file → env vars → CLI flags. `--theme` + `--no-colors` prints a warning and applies the theme.
 
 <details>
 <summary>Color customization flags (click to expand)</summary>
@@ -338,6 +339,8 @@ All color options accept hex values (`#rrggbb`) and have corresponding `REVDIFF_
 | `--color-add-bg` | Added line background | `#123800` |
 | `--color-remove-fg` | Removed line text | `#ff8787` |
 | `--color-remove-bg` | Removed line background | `#4D1100` |
+| `--color-word-add-bg` | Intra-line word-diff add background | auto-derived from add-bg |
+| `--color-word-remove-bg` | Intra-line word-diff remove background | auto-derived from remove-bg |
 | `--color-modify-fg` | Modified line text (collapsed mode) | `#f5c542` |
 | `--color-modify-bg` | Modified line background (collapsed mode) | `#3D2E00` |
 | `--color-tree-bg` | File tree pane background | terminal default |