feat: change css to use single brand color, only new browsers support

package.json

@@ -9,6 +9,7 @@
     "preview": "vite preview",
     "prepare": "svelte-kit sync || echo ''",
     "check": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json",
+    "lint:css": "stylelint '**/*.{css,svelte}",
     "check:watch": "svelte-kit sync && svelte-check --tsconfig ./tsconfig.json --watch",
     "test": "vitest",
     "test:ui": "vitest --ui",
@@ -32,8 +33,12 @@
     "@types/node": "^25.1.0",
     "@vitest/coverage-istanbul": "^4.0.18",
     "@vitest/ui": "^4.0.18",
+    "glob": "^13.0.2",
     "jsdom": "^28.0.0",
     "konva": "^10.2.0",
+    "stylelint": "^17.2.0",
+    "stylelint-config-html": "^1.1.0",
+    "stylelint-config-recommended": "^18.0.0",
     "svelte": "^5.48.2",
     "svelte-check": "^4.3.5",
     "typescript": "^5.9.3",