feat(web/m7-362): tokens.json dark/light/flat split + dual-block CSS generator

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

web/scripts/tokens-to-css.js

@@ -2,7 +2,7 @@
 // Reads ../src/lib/styles/tokens.json and emits tokens.generated.css.
 // Single source of truth for FabledSword tokens shared with the Flutter
 // client. Keep output deterministic — Tailwind reads tokens.json directly,
-// the .css emission is for raw CSS consumers.
+// the .css emission is for raw CSS consumers and theme switching.
 import { readFileSync, writeFileSync } from 'node:fs';
 import { fileURLToPath } from 'node:url';
 import { dirname, resolve } from 'node:path';
@@ -10,19 +10,35 @@ import { dirname, resolve } from 'node:path';
 const here = dirname(fileURLToPath(import.meta.url));
 const tokensPath = resolve(here, '../src/lib/styles/tokens.json');
 const outPath    = resolve(here, '../src/lib/styles/tokens.generated.css');
-const tokens = JSON.parse(readFileSync(tokensPath, 'utf8'));
 
-const lines = ['/* GENERATED — do not edit. Source: tokens.json */', ':root {'];
+export function emit(tokens) {
-for (const [name, value] of Object.entries(tokens.colors)) {
+  const lines = ['/* GENERATED — do not edit. Source: tokens.json */', ':root {'];
+  for (const [name, value] of Object.entries(tokens.colors.dark)) {
     lines.push(`  --fs-${name}: ${value};`);
-}
+  }
-for (const [name, value] of Object.entries(tokens.radii)) {
+  for (const [name, value] of Object.entries(tokens.colors.flat)) {
+    lines.push(`  --fs-${name}: ${value};`);
+  }
+  for (const [name, value] of Object.entries(tokens.radii)) {
     lines.push(`  --fs-radius-${name}: ${value};`);
-}
+  }
-lines.push(`  --fs-font-display: ${tokens.fontStacks.display};`);
+  lines.push(`  --fs-font-display: ${tokens.fontStacks.display};`);
-lines.push(`  --fs-font-body: ${tokens.fontStacks.body};`);
+  lines.push(`  --fs-font-body: ${tokens.fontStacks.body};`);
-lines.push(`  --fs-font-mono: ${tokens.fontStacks.mono};`);
+  lines.push(`  --fs-font-mono: ${tokens.fontStacks.mono};`);
-lines.push('}', '[data-fs-app="minstrel"] {', `  --fs-accent: ${tokens.colors.accent};`, '}', '');
+  lines.push('}');
 
-writeFileSync(outPath, lines.join('\n'));
+  lines.push('[data-theme="light"] {');
-console.log(`wrote ${outPath}`);
+  for (const [name, value] of Object.entries(tokens.colors.light)) {
+    lines.push(`  --fs-${name}: ${value};`);
+  }
+  lines.push('}');
+
+  lines.push('[data-fs-app="minstrel"] {', `  --fs-accent: ${tokens.colors.flat.accent};`, '}', '');
+  return lines.join('\n');
+}
+
+if (import.meta.url === `file://${process.argv[1]}`) {
+  const tokens = JSON.parse(readFileSync(tokensPath, 'utf8'));
+  writeFileSync(outPath, emit(tokens));
+  console.log(`wrote ${outPath}`);
+}

web/src/lib/styles/tokens.generated.css

@@ -0,0 +1,37 @@
+/* GENERATED — do not edit. Source: tokens.json */
+:root {
+  --fs-obsidian: #14171A;
+  --fs-iron: #1E2228;
+  --fs-slate: #2C313A;
+  --fs-pewter: #3F4651;
+  --fs-parchment: #E8E4D8;
+  --fs-vellum: #C2BFB4;
+  --fs-ash: #9C9A92;
+  --fs-moss: #4A5D3F;
+  --fs-bronze: #8B7355;
+  --fs-oxblood: #6B2118;
+  --fs-warning: #8B6F1E;
+  --fs-error: #C04A1F;
+  --fs-info: #3D5A6E;
+  --fs-accent: #4A6B5C;
+  --fs-on-action: #E8E4D8;
+  --fs-radius-sm: 4px;
+  --fs-radius-md: 8px;
+  --fs-radius-lg: 12px;
+  --fs-radius-xl: 16px;
+  --fs-font-display: 'Fraunces', Georgia, serif;
+  --fs-font-body: 'Inter', system-ui, sans-serif;
+  --fs-font-mono: 'JetBrains Mono', ui-monospace, monospace;
+}
+[data-theme="light"] {
+  --fs-obsidian: #F8F5EE;
+  --fs-iron: #ECE6D5;
+  --fs-slate: #DCD3BD;
+  --fs-pewter: #B8AE94;
+  --fs-parchment: #14171A;
+  --fs-vellum: #2C313A;
+  --fs-ash: #5C6068;
+}
+[data-fs-app="minstrel"] {
+  --fs-accent: #4A6B5C;
+}

web/src/lib/styles/tokens.json

@@ -1,31 +1,36 @@
 {
   "colors": {
+    "dark": {
       "obsidian": "#14171A",
       "iron": "#1E2228",
       "slate": "#2C313A",
       "pewter": "#3F4651",
       "parchment": "#E8E4D8",
       "vellum": "#C2BFB4",
-    "ash": "#9C9A92",
+      "ash": "#9C9A92"
+    },
+    "light": {
+      "obsidian": "#F8F5EE",
+      "iron": "#ECE6D5",
+      "slate": "#DCD3BD",
+      "pewter": "#B8AE94",
+      "parchment": "#14171A",
+      "vellum": "#2C313A",
+      "ash": "#5C6068"
+    },
+    "flat": {
       "moss": "#4A5D3F",
       "bronze": "#8B7355",
       "oxblood": "#6B2118",
       "warning": "#8B6F1E",
       "error": "#C04A1F",
       "info": "#3D5A6E",
-    "accent": "#4A6B5C"
+      "accent": "#4A6B5C",
-  },
+      "on-action": "#E8E4D8"
-  "radii": {
+    }
-    "sm": "4px",
-    "md": "8px",
-    "lg": "12px",
-    "xl": "16px"
-  },
-  "fonts": {
-    "display": "Fraunces",
-    "body": "Inter",
-    "mono": "JetBrains Mono"
   },
+  "radii": { "sm": "4px", "md": "8px", "lg": "12px", "xl": "16px" },
+  "fonts": { "display": "Fraunces", "body": "Inter", "mono": "JetBrains Mono" },
   "fontStacks": {
     "display": "'Fraunces', Georgia, serif",
     "body": "'Inter', system-ui, sans-serif",