/* ==========================================================================
   LUMINA LEARN DESIGN SYSTEM
   Design tokens, Theme variables, Glassmorphism, 3D Tactile Buttons & Glows
   ========================================================================== */

:root {
  /* Fonts */
  --font-headline: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-body: 'Be Vietnam Pro', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

  /* Theme Tokens - Light Mode Default */
  --bg-main: #f8f9ff;
  --bg-surface: #ffffff;
  --bg-surface-container: #eff4ff;
  --bg-surface-container-high: #e2ecfc;
  --bg-surface-container-highest: #d5e3fc;
  --bg-card: rgba(255, 255, 255, 0.85);
  --border-subtle: rgba(13, 28, 46, 0.08);
  --border-strong: rgba(13, 28, 46, 0.16);

  --text-primary: #0d1c2e;
  --text-secondary: #4d596a;
  --text-muted: #7f8c9f;
  --text-inverse: #ffffff;

  /* Vibrant Accent Palette */
  --primary-yellow: #ffd640;
  --primary-yellow-hover: #ffca1a;
  --primary-yellow-dim: #eac32c;
  --primary-yellow-shadow: #cda800;

  --accent-green: #22c55e;
  --accent-green-light: #4ade80;
  --accent-green-dark: #15803d;
  --accent-green-shadow: #166534;
  --accent-green-bg: rgba(34, 197, 94, 0.12);

  --accent-blue: #3b82f6;
  --accent-blue-light: #60a5fa;
  --accent-blue-dark: #1d4ed8;
  --accent-blue-bg: rgba(59, 130, 246, 0.12);

  --accent-error: #ef4444;
  --accent-error-dark: #b91c1c;
  --accent-error-bg: rgba(239, 68, 68, 0.12);

  --accent-gold: #f59e0b;
  --accent-purple: #8b5cf6;
  --accent-orange: #f97316;

  /* Glassmorphism & Elevation */
  --glass-bg: rgba(255, 255, 255, 0.75);
  --glass-border: rgba(255, 255, 255, 0.6);
  --glass-shadow: 0 12px 32px rgba(13, 28, 46, 0.08);
  --card-shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
  --modal-backdrop: rgba(13, 28, 46, 0.6);

  /* Tactile Button Shadows */
  --btn-3d-yellow: 0 4px 0 0 #cda800, 0 8px 20px rgba(255, 214, 64, 0.35);
  --btn-3d-green: 0 4px 0 0 #15803d, 0 8px 20px rgba(34, 197, 94, 0.35);
  --btn-3d-blue: 0 4px 0 0 #1d4ed8, 0 8px 20px rgba(59, 130, 246, 0.35);
  --btn-3d-surface: 0 4px 0 0 rgba(0, 0, 0, 0.08);

  /* Radii */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --radius-full: 9999px;

  /* Transitions */
  --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-normal: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-spring: 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

/* ==========================================================================
   Dark Theme (Default Stitch Style)
   ========================================================================== */
html.dark {
  --bg-main: #0d0f17;
  --bg-surface: #12141c;
  --bg-surface-container: #1a1d29;
  --bg-surface-container-high: #242838;
  --bg-surface-container-highest: #2e3347;
  --bg-card: rgba(30, 34, 48, 0.75);
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-strong: rgba(255, 255, 255, 0.18);

  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --text-inverse: #0d1c2e;

  --primary-yellow: #ffd954;
  --primary-yellow-hover: #ffe07e;
  --primary-yellow-dim: #eac32c;
  --primary-yellow-shadow: #a88500;

  --accent-green: #5eeb93;
  --accent-green-light: #6dfe9c;
  --accent-green-dark: #00924a;
  --accent-green-shadow: #005227;
  --accent-green-bg: rgba(94, 235, 147, 0.15);

  --accent-blue: #60a5fa;
  --accent-blue-light: #93c5fd;
  --accent-blue-dark: #2563eb;
  --accent-blue-bg: rgba(96, 165, 250, 0.15);

  --accent-error: #ff7675;
  --accent-error-dark: #d63031;
  --accent-error-bg: rgba(255, 118, 117, 0.15);

  --glass-bg: rgba(30, 34, 48, 0.78);
  --glass-border: rgba(255, 255, 255, 0.1);
  --glass-shadow: 0 16px 40px rgba(0, 0, 0, 0.5);
  --card-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
  --modal-backdrop: rgba(10, 12, 18, 0.85);

  --btn-3d-yellow: 0 4px 0 0 #a88500, 0 8px 24px rgba(255, 217, 84, 0.3);
  --btn-3d-green: 0 4px 0 0 #005227, 0 8px 24px rgba(94, 235, 147, 0.35);
  --btn-3d-blue: 0 4px 0 0 #1d4ed8, 0 8px 24px rgba(96, 165, 250, 0.35);
  --btn-3d-surface: 0 4px 0 0 #12141c;
}

/* Reset & Base Setup */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-body);
  background-color: var(--bg-main);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  transition: background-color var(--transition-normal), color var(--transition-normal);
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-headline);
  font-weight: 700;
  color: var(--text-primary);
}

/* Tactile 3D Buttons */
.btn-3d {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-headline);
  font-weight: 700;
  font-size: 1rem;
  padding: 14px 28px;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  text-decoration: none;
  user-select: none;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), filter var(--transition-fast);
}

.btn-3d:active {
  transform: translateY(3px);
  box-shadow: none !important;
}

.btn-3d-green {
  background: linear-gradient(180deg, var(--accent-green-light) 0%, var(--accent-green) 100%);
  color: #002911;
  box-shadow: var(--btn-3d-green);
}
.btn-3d-green:hover {
  filter: brightness(1.08);
}

.btn-3d-yellow {
  background: linear-gradient(180deg, var(--primary-yellow-hover) 0%, var(--primary-yellow) 100%);
  color: #231b00;
  box-shadow: var(--btn-3d-yellow);
}
.btn-3d-yellow:hover {
  filter: brightness(1.08);
}

.btn-3d-blue {
  background: linear-gradient(180deg, var(--accent-blue-light) 0%, var(--accent-blue) 100%);
  color: #ffffff;
  box-shadow: var(--btn-3d-blue);
}
.btn-3d-blue:hover {
  filter: brightness(1.08);
}

.btn-3d-surface {
  background-color: var(--bg-surface-container-high);
  color: var(--text-primary);
  border: 1px solid var(--border-subtle);
  box-shadow: var(--btn-3d-surface);
}
.btn-3d-surface:hover {
  background-color: var(--bg-surface-container-highest);
}

/* Glassmorphism Panels */
.glass-panel {
  background: var(--glass-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  box-shadow: var(--glass-shadow);
}

/* Ambient Glows */
.glow-gold {
  box-shadow: 0 0 35px rgba(255, 217, 84, 0.35);
}

.glow-green {
  box-shadow: 0 0 35px rgba(94, 235, 147, 0.35);
}

.glow-blue {
  box-shadow: 0 0 35px rgba(96, 165, 250, 0.35);
}

/* Interactive Card Hover */
.tactile-card {
  background: var(--bg-surface-container);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  transition: all var(--transition-spring);
  cursor: pointer;
}

.tactile-card:hover {
  transform: translateY(-4px) scale(1.01);
  border-color: var(--accent-blue-light);
  box-shadow: 0 12px 28px rgba(0, 0, 0, 0.15);
}

/* Custom Scrollbar */
::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-main);
}

::-webkit-scrollbar-thumb {
  background: var(--bg-surface-container-highest);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--accent-blue);
}