/* ============================================================
   luoai.asia Design Tokens — Unified Design System v2.0
   Taste-skill calibrated: Zinc neutrals, Teal accent, no AI-slops
   ============================================================ */

/* ---------- Light Theme (default) ---------- */
:root {
  /* Accent */
  --color-accent: #0d9488;
  --color-accent-hover: #0f766e;
  --color-accent-light: rgba(13, 148, 136, 0.12);
  --color-accent-glow: rgba(13, 148, 136, 0.25);

  /* Neutrals — Zinc scale */
  --color-bg: #fafafa;
  --color-bg-alt: #f4f4f5;
  --color-surface: #ffffff;
  --color-surface-hover: #f4f4f5;
  --color-surface-elevated: #ffffff;
  --color-border: #e4e4e7;
  --color-border-light: #f4f4f5;

  /* Text */
  --color-text-primary: #18181b;
  --color-text-secondary: #52525b;
  --color-text-tertiary: #a1a1aa;
  --color-text-inverse: #fafafa;

  /* States */
  --color-success: #22c55e;
  --color-warning: #f59e0b;
  --color-danger: #ef4444;
  --color-info: #3b82f6;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.12);
  --shadow-glow: 0 0 24px var(--color-accent-glow);

  /* Radius */
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-full: 9999px;

  /* Spacing — 4px grid */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-8: 32px;
  --space-10: 40px;
  --space-12: 48px;
  --space-16: 64px;

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Noto Sans SC', sans-serif;
  --font-mono: 'SF Mono', 'Cascadia Code', 'Fira Code', Consolas, 'Liberation Mono', Menlo, monospace;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 350ms ease;

  /* Layout */
  --max-width: 1200px;
  --nav-height: 64px;

  /* Glass */
  --glass-bg: rgba(255, 255, 255, 0.72);
  --glass-border: rgba(255, 255, 255, 0.6);
  --glass-blur: 16px;
}

/* ---------- Dark Theme ---------- */
[data-theme="dark"] {
  --color-accent: #2dd4bf;
  --color-accent-hover: #5eead4;
  --color-accent-light: rgba(45, 212, 191, 0.12);
  --color-accent-glow: rgba(45, 212, 191, 0.2);

  --color-bg: #09090b;
  --color-bg-alt: #18181b;
  --color-surface: #18181b;
  --color-surface-hover: #27272a;
  --color-surface-elevated: #27272a;
  --color-border: #27272a;
  --color-border-light: #3f3f46;

  --color-text-primary: #fafafa;
  --color-text-secondary: #a1a1aa;
  --color-text-tertiary: #71717a;
  --color-text-inverse: #18181b;

  --color-success: #4ade80;
  --color-warning: #fbbf24;
  --color-danger: #f87171;
  --color-info: #60a5fa;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.5);
  --shadow-glow: 0 0 32px var(--color-accent-glow);

  --glass-bg: rgba(24, 24, 27, 0.72);
  --glass-border: rgba(255, 255, 255, 0.08);
  --glass-blur: 16px;
}

/* ---------- Global Reset ---------- */
*, *::before, *::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  font-family: var(--font-sans);
  font-size: var(--font-size-base);
  line-height: 1.6;
  color: var(--color-text-primary);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color var(--transition-normal),
              color var(--transition-normal);
}

/* ---------- Theme Toggle Button ---------- */
.theme-toggle {
  position: fixed;
  top: var(--space-4);
  right: var(--space-4);
  z-index: 100;
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  color: var(--color-text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  transition: background var(--transition-fast),
              transform var(--transition-fast),
              box-shadow var(--transition-fast);
  -webkit-tap-highlight-color: transparent;
}

.theme-toggle:hover {
  background: var(--color-surface-hover);
  transform: scale(1.08);
  box-shadow: var(--shadow-sm);
}

.theme-toggle:active {
  transform: scale(0.95);
}

/* ---------- Utility Classes ---------- */
.text-accent { color: var(--color-accent); }
.bg-accent { background-color: var(--color-accent); }
.text-secondary { color: var(--color-text-secondary); }
.text-tertiary { color: var(--color-text-tertiary); }

/* Scrollbar styling */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--color-border);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--color-text-tertiary);
}

/* Focus ring */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 2px;
}

/* Selection */
::selection {
  background: var(--color-accent-light);
  color: var(--color-text-primary);
}