/* A.I. ClassMate Design System */
:root {
  /* ── Colors (HSL) ── */
  --background: 210 40% 99%;
  --foreground: 222 47% 11%;
  --primary: 221 83% 53%;
  --primary-foreground: 210 40% 98%;
  --secondary: 210 40% 96%;
  --secondary-foreground: 222 47% 11%;
  --accent: 188 85% 92%;
  --accent-foreground: 222 47% 11%;
  --muted: 210 40% 96%;
  --muted-foreground: 215 16% 47%;
  --destructive: 0 84% 60%;
  --border: 214 32% 91%;
  --ring: 221 83% 53%;
  --card: 0 0% 100%;
  --card-foreground: 222 47% 11%;

  /* Extra semantic tokens */
  --success: 142 71% 45%;
  --warning: 38 92% 50%;
  --info: 199 89% 48%;

  /* ── Shadows ── */
  --shadow-sm: 0 1px 2px 0 hsl(var(--foreground) / 0.05);
  --shadow-md: 0 4px 6px -1px hsl(var(--foreground) / 0.08), 0 2px 4px -2px hsl(var(--foreground) / 0.05);
  --shadow-lg: 0 10px 15px -3px hsl(var(--foreground) / 0.08), 0 4px 6px -4px hsl(var(--foreground) / 0.03);
  --shadow-elegant: 0 12px 34px -14px hsl(var(--primary) / 0.35);

  /* ── Gradients ── */
  --gradient-primary: linear-gradient(135deg, hsl(var(--primary)), hsl(var(--info) / 0.9));
  --gradient-subtle: linear-gradient(135deg, hsl(var(--background)), hsl(var(--secondary)));
  --gradient-hero: radial-gradient(1200px 600px at 10% 10%, hsl(var(--accent) / 0.9), transparent 60%), radial-gradient(900px 500px at 90% 20%, hsl(var(--primary) / 0.18), transparent 55%), linear-gradient(180deg, hsl(var(--background)), hsl(var(--secondary) / 0.6));

  /* ── Transitions ── */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-smooth: 300ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);

  /* ── Border Radius ── */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;

  /* Typography */
  --font-sans: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  --font-display: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial;
}

.dark, [data-theme="dark"] {
  --background: 222 47% 11%;
  --foreground: 210 40% 98%;
  --primary: 217 91% 60%;
  --primary-foreground: 222 47% 11%;
  --secondary: 217 33% 17%;
  --secondary-foreground: 210 40% 98%;
  --accent: 190 85% 18%;
  --accent-foreground: 210 40% 98%;
  --muted: 217 33% 17%;
  --muted-foreground: 215 20% 70%;
  --destructive: 0 84% 60%;
  --border: 217 33% 22%;
  --ring: 217 91% 60%;
  --card: 222 47% 13%;
  --card-foreground: 210 40% 98%;

  --shadow-sm: 0 1px 2px 0 hsl(var(--foreground) / 0.06);
  --shadow-md: 0 4px 10px -2px hsl(0 0% 0% / 0.35);
  --shadow-lg: 0 18px 30px -16px hsl(0 0% 0% / 0.55);
  --shadow-elegant: 0 18px 44px -18px hsl(var(--primary) / 0.35);

  --gradient-hero: radial-gradient(1200px 600px at 10% 10%, hsl(var(--accent) / 0.55), transparent 60%), radial-gradient(900px 500px at 90% 20%, hsl(var(--primary) / 0.22), transparent 55%), linear-gradient(180deg, hsl(var(--background)), hsl(var(--secondary) / 0.6));
}

html, body {
  font-family: var(--font-sans);
}

/* Focus styles */
:focus-visible {
  outline: none;
  box-shadow: 0 0 0 3px hsl(var(--ring) / 0.35);
  border-radius: var(--radius-sm);
}

/* Subtle animated background for hero */
.hero-bg {
  background: var(--gradient-hero);
}

/* Token-based helpers */
.card {
  background: hsl(var(--card));
  color: hsl(var(--card-foreground));
  border: 1px solid hsl(var(--border));
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
}

.btn {
  border-radius: var(--radius-md);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), background var(--transition-fast), color var(--transition-fast);
}

.btn:active {
  transform: translateY(1px);
}

/* Skeleton */
.skeleton {
  background: linear-gradient(90deg, hsl(var(--muted)) 0%, hsl(var(--secondary)) 50%, hsl(var(--muted)) 100%);
  background-size: 200% 100%;
  animation: shimmer 1.2s ease-in-out infinite;
  border-radius: var(--radius-md);
}

@keyframes shimmer {
  0% { background-position: 200% 0; }
  100% { background-position: -200% 0; }
}

/* Reduce motion */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 1ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 1ms !important;
    scroll-behavior: auto !important;
  }
}