Kordant/tasks/shieldai-unified-restructure/02-theme-system-brand-palette.md

02. Theme System — Auto-Shifting CSS with ShieldAI Brand Palette

meta: id: shieldai-unified-restructure-02 feature: shieldai-unified-restructure priority: P0 depends_on: [shieldai-unified-restructure-01] tags: [frontend, design-system, css, theme]

objective:

• Create a comprehensive, auto-shifting CSS theme system for the web app using Tailwind v4 @theme and CSS custom properties with @property animations, adapted from the Lendair reference but using a ShieldAI-appropriate brand palette.

deliverables:

• web/src/app.css — Complete theme file with:
  • @property declarations for all animatable color tokens
  • :root light-mode color tokens (backgrounds, text, brand, borders, semantic, glass)
  • @media (prefers-color-scheme: dark) dark-mode overrides
  • :root.light and :root.dark manual override classes
  • @theme block registering all tokens for Tailwind v4
  • Base styles (html, body, *:focus-visible)
  • Utility classes (gradients, glassmorphism, gradient text, glow shadows, dot-grid background, noise texture)
• Global background dot-grid pattern and smooth 500ms color transitions
• Typography scale using Inter font family
• Spacing and radius scale aligned with Lendair's design

steps:

1. Copy the Lendair app.css structure from ~/code/Lendair/web/src/app.css as the scaffold.
2. Replace the brand color tokens with ShieldAI palette:
   • Primary: deep indigo #4f46e5 (brand-primary), light #818cf8 (brand-primary-light), dark #4338ca (brand-primary-dark)
   • Accent: electric cyan #06b6d4 (brand-accent), light #67e8f9 (brand-accent-light), dark #0891b2 (brand-accent-dark)
   • Alert/Danger: amber #f59e0b (warning), red #ef4444 (error)
   • Keep neutral grays from Lendair for backgrounds and text
3. Add @property declarations for every custom property that should animate smoothly.
4. Define @theme block with all tokens so Tailwind v4 utility classes resolve correctly.
5. Implement prefers-color-scheme: dark media query with full dark palette.
6. Add .light and .dark classes on :root for manual JS toggling.
7. Define utility classes:
   • .gradient-primary, .gradient-accent, .gradient-subtle, .gradient-card
   • .glass, .glass-dark
   • .text-gradient-primary, .text-gradient-accent
   • .shadow-glow-primary, .shadow-glow-accent
   • .bg-dot-grid, .bg-noise
8. Set global background-color, background-image (dot-grid), and transition on :root and body.
9. Import the CSS in web/src/entry-client.tsx or web/src/app.tsx (whichever is the root).
10. Create a small useTheme() hook in web/src/lib/theme.ts that detects prefers-color-scheme, exposes theme signal, and toggles .light/.dark on document.documentElement.

tests:

• Unit: useTheme() hook returns correct initial theme based on media query; toggling updates class and signal
• Visual: Open app in light and dark OS modes; verify all colors shift smoothly over 500ms
• Visual: Toggle theme manually via useTheme(); verify override persists across reloads (localStorage)

acceptance_criteria:

• All color tokens animate smoothly between light/dark modes
• Tailwind utilities like text-brand-primary, bg-bg-secondary, border-border work correctly
• Manual theme toggle (light/dark/system) functions and persists
• Dot-grid background pattern renders correctly in both modes
• No FOUC (flash of unstyled content) on initial load

validation:

• Open http://localhost:3000 in browser DevTools
• Toggle OS dark mode; verify background, text, and card colors shift
• Run document.documentElement.classList.add('dark') in console; verify immediate dark mode
• Check computed styles for --color-bg and confirm it matches token values

notes:

• Reference: ~/code/Lendair/web/src/app.css — this is the exact structure we want, just with ShieldAI colors.
• Tailwind v4 @theme is compile-time; changing tokens requires rebuild. Runtime theme switching uses CSS custom properties.
• The transition on :root and body must include background-color and color for smooth shifts.
• Consider adding a theme-color meta tag that updates with the theme for mobile browsers.