feat(tui): add Dune Dark theme and keep light Dune

CHANGELOG.md

@@ -235,12 +235,12 @@ tagged. Until then, source builds report the version `dev`.
   GitHub issue/PR templates.
 - Interactive `/theme` picker: bare `/theme` opens a popup that live-previews each palette as you move
   and applies on select (Esc reverts).
-- Twelve built-in color themes alongside the `dark`/`light` built-ins — `dracula`, `nord`, `gruvbox`,
+- Thirteen built-in color themes alongside the `dark`/`light` built-ins — `dracula`, `nord`, `gruvbox`,
   `tokyo-night`, `catppuccin`, `one-dark`, `solarized-dark`, `rose-pine`, `everforest`,
-  `solarized-light`, `dune`, and `neon` — selectable via `/theme <name>`, `--theme <name>`, or
+  `solarized-light`, `dune`, `dune-dark`, and `neon` — selectable via `/theme <name>`, `--theme <name>`, or
   `ZERO_THEME`. Every palette is contrast-audited to WCAG AA, and the new presets are additionally
-  audited after xterm-256 downsampling; see [docs/THEMES.md](docs/THEMES.md). The built-in light
-  theme was reworked for legibility.
+  audited after xterm-256 downsampling (Dune Dark also after 16-color ANSI conversion); see
+  [docs/THEMES.md](docs/THEMES.md). The built-in light theme was reworked for legibility.
 - `--theme <name>` flag for the TUI, accepting `auto` or any registered theme (previously only the
   `ZERO_THEME` env var existed).
 - "Accessibility / Appearance" section in the README documenting `NO_COLOR`, `ZERO_THEME`, `/theme`,

README.md

@@ -342,7 +342,7 @@ manifest.
 | Control | Effect |
 |---|---|
 | `NO_COLOR=<anything>` | disables color output |
-| `ZERO_THEME=<name>` | selects the startup theme (`auto`, `dark`, `light`, or a color theme like `dracula`, `nord`, `gruvbox`, `tokyo-night`, `catppuccin`, `one-dark`, `solarized-dark`, `rose-pine`, `everforest`, `neon`, `solarized-light`, `dune`) |
+| `ZERO_THEME=<name>` | selects the startup theme (`auto`, `dark`, `light`, or a color theme like `dracula`, `nord`, `gruvbox`, `tokyo-night`, `catppuccin`, `one-dark`, `solarized-dark`, `rose-pine`, `everforest`, `neon`, `dune-dark`, `solarized-light`, `dune`) |
 | `--theme <name>` | selects the TUI theme from the CLI (same names) |
 | `/theme` | opens the theme picker inside the TUI (live preview; `/theme <name>` switches directly) |
 | `ZERO_NO_FADE=1` | disables streaming fade animation |

README_ZH.md

@@ -234,7 +234,7 @@ zero update           检查更新版本
 | 控制 | 效果 |
 |---|---|
 | `NO_COLOR=<任意值>` | 禁用颜色输出 |
-| `ZERO_THEME=<名称>` | 选择启动主题（`auto`、`dark`、`light`，或颜色主题如 `dracula`、`nord`、`gruvbox`、`tokyo-night`、`catppuccin`、`one-dark`、`solarized-dark`、`rose-pine`、`everforest`、`neon`、`solarized-light`、`dune`） |
+| `ZERO_THEME=<名称>` | 选择启动主题（`auto`、`dark`、`light`，或颜色主题如 `dracula`、`nord`、`gruvbox`、`tokyo-night`、`catppuccin`、`one-dark`、`solarized-dark`、`rose-pine`、`everforest`、`neon`、`dune-dark`、`solarized-light`、`dune`） |
 | `--theme <名称>` | 从 CLI 选择 TUI 主题（相同名称） |
 | `/theme` | 在 TUI 中打开主题选择器（实时预览；`/theme <名称>` 直接切换） |
 | `ZERO_NO_FADE=1` | 禁用流式淡入动画 |

docs/THEMES.md

@@ -11,8 +11,14 @@ the active theme and the registered names without opening the picker.
 
 ## Dune (`dune`)
 
-A warm sand-and-cream palette: sand/cream surface, charcoal ink, and a soft
-amber accent.
+A warm sand-and-cream palette with charcoal ink, soft amber accent, and
+quantization-safe diff bands.
+
+## Dune Dark (`dune-dark`)
+
+A dark, colorblind-friendly palette inspired by Claude Code's daltonized dark palette:
+near-black surface, white ink, and a deuteranopia-adjusted brand-orange
+accent.
 
 ## Neon (`neon`)
 
@@ -28,12 +34,14 @@ adding a new `palette{...}` literal, a `themeRegistry` entry, and test
 coverage for the new palette (see below).
 
 Registry-wide tests in `internal/tui/theme_select_test.go` assert the basic
-WCAG AA text tokens, the gray-ramp order, the diff word-span pairs, and the
-selected-row band for every entry. The rendered-surface invariants beyond
-those (permission surfaces, selected-row secondary text, diff gutters, and
-the xterm-256 downsampling checks) are asserted per palette, not against the
-whole registry: `TestExtendedThemeContrastInvariants` and
-`TestExtendedThemeANSI256Contrast` enumerate the palettes they cover. A new
-theme must be added to those tests (or given equivalent palette-specific
-assertions), or CI can stay green while its permission, selected-row, and
-diff surfaces ship unreadable.
+WCAG AA text tokens, the gray-ramp order, the selected-row band, and (via
+`TestDiffHighlightWordSpans`) the word-span *contrast* pairs for every
+entry. The remaining rendered-surface invariants (permission surfaces,
+selected-row secondary text, xterm-256 quantization, and the quantized
+add/del band *identity* check that `addBg`/`delBg` stay green/red and
+distinct) are asserted per palette, not against the whole registry:
+`TestExtendedThemeContrastInvariants` and `TestExtendedThemeANSI256Contrast`
+enumerate the palettes they cover. A new theme must be added to those
+tests (or given equivalent palette-specific assertions), or CI can stay
+green while its permission, selected-row, and quantized-diff surfaces
+ship unreadable.

internal/tui/theme_palettes.go

@@ -444,17 +444,17 @@ var dunePalette = palette{
 	muted:     "#473e32",
 	faint:     "#554a3a",
 	faintest:  "#655648",
-	accent:    "#724028", // darkened from #8f5215 for AA on selBg (5.46:1) that also survives ANSI-256 downsampling (quantizes to #444444, 6.47:1 on quantized selBg; the previous #7c4712 quantized to #875f00 at 3.81:1)
+	accent:    "#5f4b30", // darkened from #8f5215 for AA on selBg (5.46:1) that also survives ANSI-256 downsampling (quantizes to #444444, 6.47:1 on quantized selBg)
 	green:     "#38572a",
-	red:       "#872d24", // darkened from #963328 so delBg contrast survives ANSI-256 downsampling (true 6.57:1, 256 7.86:1)
+	red:       "#872d24", // darkened from #963328 so delBg contrast survives ANSI-256 downsampling
 	amber:     "#6d4600",
-	blue:      "#2f5680", // darkened from #3d6a9e for AA on selBg (was 3.61:1, now 4.90:1)
+	blue:      "#2f5680",
 	gitAdd:    "#38572a",
 	gitDel:    "#963328",
-	addBg:     "#dcecd0",
-	delBg:     "#f5dbd5",
-	addBgWord: "#b9dc9e",
-	delBgWord: "#eebba9",
+	addBg:     "#d0f0c0", // quantizes to xterm green #d7ffd7, keeping add/del rows distinct on 256-color terminals
+	delBg:     "#fcd8d4", // quantizes to xterm red #ffd7d7
+	addBgWord: "#a5e090",
+	delBgWord: "#f8b8af",
 	permBg:    "#f0dfae",
 	selBg:     "#e0cf98",
 	addInk:    "#264018",
@@ -465,6 +465,67 @@ var dunePalette = palette{
 	cardPerm:  "#c2a04a",
 }
 
+// duneDarkPalette is a dark theme inspired by Claude Code's colorblind-friendly
+// (daltonized) dark palette. The base surface is near-black (Claude Code's true
+// dark canvas), with white ink and the brand-orange accent adjusted for
+// deuteranopia. Diff signals reuse the proven dark-theme structure so every
+// WCAG-AA invariant still holds; the accent and status colors (cool success,
+// warm error, amber warning) follow a daltonized palette so additions stay
+// distinguishable under color blindness.
+//
+// 16-color terminals (TERM=xterm) force every token through ansi.Convert16.
+// Saturated cyan/blue success and bright red error both collapse onto ANSI
+// pairs that fail AA on the green/maroon diff bands (bright-blue-on-green
+// 1.67:1, bright-red-on-maroon 2.74:1). Soft periwinkle success and soft pink
+// error map to ANSI white, which clears AA on those bands while keeping a
+// cool/warm tint in truecolor and 256-color.
+var duneDarkPalette = palette{
+	panel:    "#0e0e10", // Claude Code dark canvas — near-black
+	promptBg: "#262626", // submitted user-prompt bubble
+	line:     "#242429", // borders/separators
+	line2:    "#414147",
+	ink:      "#ececee",
+	// Gray ramp (ink > muted > faint > faintest > panel) is kept light enough
+	// that faintest maps to ANSI white / xterm #c6c6c6 and clears WCAG AA on the
+	// green add gutter under both 16-color and 256-color profiles. Prior cyan
+	// #55c6cd mapped to bright cyan at only 4.10:1 on ANSI green (short of AA).
+	muted:    "#e0e0e6", // secondary text
+	faint:    "#d4d4dc", // hints/metadata
+	faintest: "#c8c8d0", // line numbers/separators (and diff gutters)
+	// Warm sand-gold so TERM=xterm maps to ANSI yellow (brand #ff9628 maps to
+	// red at only 4.00:1 on the navy selection band under 16-color).
+	accent:    "#fff080",
+	green:     "#c8c8e9", // success — soft periwinkle (cool/daltonized). Maps to ANSI white so add-sign text stays AA (5.14:1) on the green add band under 16-color; saturated cyan/blue collapses to bright blue at 1.67:1
+	red:       "#ffc0c8", // error — soft pink. Maps to ANSI white so del-sign text stays AA (10.95:1) on the maroon del band under 16-color; bright red collapses to 2.74:1 on maroon
+	amber:     "#ffcc00", // warning rgb(255,204,0)
+	blue:      "#cceeff", // permission — light sky. Maps to bright cyan so selected-row local-model dots stay AA on black selBg under 16-color (prior #99ccff -> bright blue at 2.44:1)
+	gitAdd:    "#c8c8e9", // matches green (daltonized cool success)
+	gitDel:    "#ffc0c8", // matches red (daltonized warm error)
+	addBg:     "#003500", // diff added band — quantizes to xterm green #005f00 instead of the same gray as delBg, keeping add/del rows distinct on 256-color terminals (previous #0a1f14/#240a0e both collapsed to #121212); 16-color maps to ANSI green
+	delBg:     "#350000", // diff removed band — quantizes to xterm red #5f0000 (see addBg); 16-color maps to ANSI maroon
+	addBgWord: "#007400", // word-level added span — quantizes to xterm green #008700, distinct from both addBg's #005f00 and delBgWord's red
+	delBgWord: "#740000", // word-level removed span — quantizes to xterm red #870000 (see addBgWord)
+	permBg:    "#1c1915",
+	// Near-black grays collapse to ANSI black with panel under TERM=xterm,
+	// erasing the full-row highlight. Deep indigo maps to navy (#000080) in
+	// 16-color and #000087 in 256-color, staying distinct from panel.
+	selBg:    "#25257a",
+	addInk:   "#f0f5d2", // changed-word text — lightened so it still clears AA (4.60:1) against addBgWord's xterm-256 quantized #008700 (the original #bdeed7 fell to 4.06:1); 16-color maps to bright yellow (4.78:1 on ANSI green)
+	delInk:   "#fff0f0", // changed-word text — near-white pink maps to ANSI white so word spans stay AA on maroon under 16-color (prior #f2c4c4 -> bright red at 2.74:1)
+	onAccent: "#000000",
+	// Status-card borders are non-text UI (WCAG 1.4.11: >=3:1 against panel).
+	// Prior cardRun #3399ff mapped to ANSI bright blue at only 2.44:1 on the
+	// black panel under 16-color. #cceeff (same as blue) maps to bright cyan
+	// and clears 3:1 in truecolor, xterm-256, and ANSI-16.
+	// cardPerm must stay distinguishable from cardErr after ANSI conversion:
+	// #ffcc00 collapsed to the same ANSI red as #ff6666; pure yellow maps to
+	// ANSI yellow so running (cyan) / error (red) / permission (yellow) stay
+	// three distinct roles under 16-color and 256-color.
+	cardRun:  "#cceeff", // running tool border: light sky / ANSI bright cyan
+	cardErr:  "#ff6666", // failed tool border: warm red / ANSI red
+	cardPerm: "#fff200", // permission border: pure yellow / ANSI yellow (was #ffcc00 -> ANSI red)
+}
+
 // themeEntry is one registered theme: Name is the /theme value + ZERO_THEME/--theme
 // token (lowercase, kebab), Label is the picker display text, and IsDark groups the
 // picker (Dark/Light sections) and drives which built-in `auto` resolves to.
@@ -491,6 +552,7 @@ var themeRegistry = []themeEntry{
 	{Name: "rose-pine", Label: "Rosé Pine", Palette: rosePinePalette, IsDark: true},
 	{Name: "everforest", Label: "Everforest", Palette: everforestPalette, IsDark: true},
 	{Name: "neon", Label: "Neon", Palette: neonPalette, IsDark: true},
+	{Name: "dune-dark", Label: "Dune Dark", Palette: duneDarkPalette, IsDark: true},
 	{Name: "light", Label: "light", Palette: lightPalette, IsDark: false},
 	{Name: "solarized-light", Label: "Solarized Light", Palette: solarizedLightPalette, IsDark: false},
 	{Name: "dune", Label: "Dune", Palette: dunePalette, IsDark: false},