/* 
  =============================================================
  TDV ECOSYSTEM DESIGN TOKENS (Linear / Vercel / Stripe Grade)
  =============================================================
*/
:root {
  /* LIGHT MODE SURFACES (Alabaster & Pure White) */
  --surface-bg: #F8FAFC;
  --surface-card: #FFFFFF;
  --surface-elevated: #F1F5F9;
  
  /* BORDERS */
  --border-subtle: rgba(0, 0, 0, 0.06);
  --border-hover: rgba(0, 0, 0, 0.12);
  
  /* SHADOWS (Surface elevation, not heavy black boxes) */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -2px rgba(0, 0, 0, 0.03);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -4px rgba(0, 0, 0, 0.02);

  /* SPRING PHYSICS & ANIMATIONS */
  --transition-spring: 150ms cubic-bezier(0.22, 1, 0.36, 1);
  --transition-spring-slow: 300ms cubic-bezier(0.22, 1, 0.36, 1);
}

html.dark {
  /* DARK MODE SURFACES (Deep Charcoal / Slate) */
  --surface-bg: #090A0F;
  --surface-card: #0F1117;
  --surface-elevated: #161922;
  
  /* BORDERS */
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-hover: rgba(255, 255, 255, 0.15);
  
  /* SHADOWS (Dark mode uses almost no shadow, relies on border & elevation) */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.5);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5);
}

/* Base resets for optical perfection */
body {
  background-color: var(--surface-bg);
  transition: background-color var(--transition-spring), color var(--transition-spring);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Typography refinements */
.tabular-nums { font-variant-numeric: tabular-nums; }
.tracking-tight { letter-spacing: -0.02em; }
.max-w-65ch { max-width: 65ch; }

/* Concentric Border Radius Utility Math */
.radius-card { border-radius: 20px; padding: 12px; }
.radius-inner { border-radius: 8px; /* 20 - 12 = 8 */ }

/* Micro-interactions: Buttons */
.btn-spring {
  transition: all var(--transition-spring);
}
.btn-spring:active {
  transform: scale(0.98);
}

/* Micro-interactions: Cards */
.card-spring {
  background-color: var(--surface-card);
  border: 1px solid var(--border-subtle);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-spring);
}
.card-spring:hover {
  border-color: var(--border-hover);
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
}

/* Skeleton Loading (No Layout Shifts) */
@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}
.skeleton-pulse {
  background: linear-gradient(90deg, var(--surface-elevated) 25%, var(--border-subtle) 50%, var(--surface-elevated) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite linear;
  border-radius: inherit;
}

/* Ensure minimum touch targets for mobile */
@media (max-width: 768px) {
  button, a.tap-target, .tap-target {
    min-height: 44px;
    min-width: 44px;
  }
}

:root {
      color-scheme: dark;
    }
    html, body {
      max-width: 100vw;
      overflow-x: clip;
      min-height: 100dvh;
      min-height: -webkit-fill-available;
    }
    html.light {
      color-scheme: light;
    }
    body {
      transition: background-color 200ms ease, color 200ms ease;
    }

    html.dark body {
      background-color: #09090b;
      color: #fafafa;
      background-image: 
        radial-gradient(ellipse 70% 40% at 50% -10%, rgba(147, 51, 234, 0.15), transparent 70%),
        radial-gradient(at 0% 0%, rgba(168, 85, 247, 0.1) 0px, transparent 50%),
        radial-gradient(at 100% 0%, rgba(244, 63, 94, 0.06) 0px, transparent 50%);
      background-attachment: fixed;
    }

    html.light body {
      background-color: #fafafa;
      color: #09090b;
      background-image: 
        radial-gradient(ellipse 70% 40% at 50% -10%, rgba(147, 51, 234, 0.06), transparent 70%),
        radial-gradient(at 0% 0%, rgba(168, 85, 247, 0.05) 0px, transparent 50%),
        radial-gradient(at 100% 0%, rgba(244, 63, 94, 0.03) 0px, transparent 50%);
      background-attachment: fixed;
    }

    .hub-card {
      background-color: #ffffff;
      border: 1px solid #e4e4e7;
      box-shadow: 0 1px 3px 0 rgba(0, 0, 0, 0.04), 0 1px 2px -1px rgba(0, 0, 0, 0.04);
      transition: transform 200ms cubic-bezier(0.16, 1, 0.3, 1), box-shadow 200ms cubic-bezier(0.16, 1, 0.3, 1), border-color 200ms ease;
    }

    html.dark .hub-card {
      background-color: #18181b;
      border: 1px solid #27272a;
      box-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.5);
    }

    .hub-card:hover {
      transform: translateY(-2px);
      box-shadow: 0 12px 24px -8px rgba(147, 51, 234, 0.12);
      border-color: rgba(147, 51, 234, 0.35);
    }

    html.dark .hub-card:hover {
      box-shadow: 0 16px 30px -10px rgba(147, 51, 234, 0.25);
      border-color: rgba(168, 85, 247, 0.45);
    }

    ::-webkit-scrollbar {
      width: 6px;
      height: 6px;
    }
    ::-webkit-scrollbar-track {
      background: transparent;
    }
    ::-webkit-scrollbar-thumb {
      background: rgba(148, 163, 184, 0.3);
      border-radius: 9999px;
    }
    ::-webkit-scrollbar-thumb:hover {
      background: rgba(147, 51, 234, 0.6);
    }

    .pulse-dot {
      animation: pulseGlow 2s infinite ease-in-out;
    }
    @keyframes pulseGlow {
      0%, 100% { opacity: 1; transform: scale(1); }
      50% { opacity: 0.35; transform: scale(0.85); }
    }

    dialog::backdrop {
      background: rgba(0, 0, 0, 0.75);
      backdrop-filter: blur(8px);
      -webkit-backdrop-filter: blur(8px);
    }