Nuxt Ui Guideline: Theming — Use @theme directive for custom colors. Description: Define design tokens in CSS with Tailwind @theme. Do: @theme { --color-brand-500: #xxx }. Don't: Inline color definitions. Good Example: @theme { --color-brand-500: #ef4444; }. Bad Example: :style="{ color: '#ef4444' }". Severity: Medium. Docs: https://ui.nuxt.com/docs/getting-started/theme/design-system.