/* ==========================================================================
   Hestens Learning - Design System & Accessibility Tokens
   ========================================================================== */

/* --- OpenDyslexic Font Face Declarations --- */
@font-face {
  font-family: 'OpenDyslexic';
  src: url('../fonts/OpenDyslexic/OpenDyslexic-Regular.otf') format('opentype');
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'OpenDyslexic';
  src: url('../fonts/OpenDyslexic/OpenDyslexic-Italic.otf') format('opentype');
  font-weight: 400;
  font-style: italic;
  font-display: swap;
}

@font-face {
  font-family: 'OpenDyslexic';
  src: url('../fonts/OpenDyslexic/OpenDyslexic-Bold.otf') format('opentype');
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

/* --- Root Variables & Theme Palettes --- */
:root {
  /* Typography Variables */
  --font-family-base: 'Lexend', system-ui, -apple-system, sans-serif;
  --font-family-opendyslexic: 'OpenDyslexic', sans-serif;
  --font-family-atkinson: 'Atkinson Hyperlegible', sans-serif;
  --font-family-sans: 'Inter', system-ui, -apple-system, sans-serif;
  
  --font-size-scale: 1;
  --base-font-size: calc(16px * var(--font-size-scale));
  --font-line-height: 1.65;
  --font-letter-spacing: 0.02em;
  --font-word-spacing: 0.05em;
  --paragraph-spacing: 1.5rem;

  /* Theme: Default Modern Dark (Calm Slate) */
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-tertiary: #334155;
  --bg-card: rgba(30, 41, 59, 0.85);
  --bg-card-hover: rgba(51, 65, 85, 0.9);
  --bg-overlay: rgba(15, 23, 42, 0.75);

  --text-primary: #f8fafc;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --text-inverse: #0f172a;

  --accent-primary: #38bdf8;
  --accent-secondary: #818cf8;
  --accent-hover: #0284c7;
  --accent-glow: rgba(56, 189, 248, 0.25);

  --success-color: #34d399;
  --success-bg: rgba(52, 211, 153, 0.15);
  --warning-color: #fbbf24;
  --warning-bg: rgba(251, 191, 36, 0.15);
  --info-color: #60a5fa;
  --info-bg: rgba(96, 165, 250, 0.15);

  --border-subtle: rgba(255, 255, 255, 0.1);
  --border-focus: #38bdf8;
  --focus-outline-width: 3px;
  --focus-outline-offset: 3px;

  /* Visual Aid Variables */
  --ruler-bg: rgba(254, 240, 138, 0.35);
  --ruler-border: #eab308;
  --ruler-height: 52px;
  --focus-mask-bg: rgba(0, 0, 0, 0.65);
  --tts-highlight-bg: #fde047;
  --tts-highlight-text: #020617;

  /* UI Tokens */
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-full: 9999px;

  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-md: 0 6px 20px rgba(0, 0, 0, 0.3);
  --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.45);
  --shadow-glow: 0 0 24px var(--accent-glow);

  --transition-speed: 0.25s;
  --transition-fn: cubic-bezier(0.16, 1, 0.3, 1);
}

/* --- Theme: Crisp Light --- */
[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f1f5f9;
  --bg-card: rgba(255, 255, 255, 0.95);
  --bg-card-hover: #ffffff;
  --bg-overlay: rgba(248, 250, 252, 0.8);

  --text-primary: #0f172a;
  --text-secondary: #334155;
  --text-muted: #64748b;
  --text-inverse: #f8fafc;

  --accent-primary: #0284c7;
  --accent-secondary: #6366f1;
  --accent-hover: #0369a1;
  --accent-glow: rgba(2, 132, 199, 0.15);

  --border-subtle: #e2e8f0;
  --border-focus: #0284c7;
  --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 6px 20px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 12px 32px rgba(0, 0, 0, 0.12);
}

/* --- Theme: Warm Sepia / Meares-Irlen Tint (Reduces Visual Stress / Glare) --- */
[data-theme="sepia"] {
  --bg-primary: #fbf0d9;
  --bg-secondary: #f4e4bc;
  --bg-tertiary: #ebd7a3;
  --bg-card: #f8ebd0;
  --bg-card-hover: #fcf4e3;
  --bg-overlay: rgba(251, 240, 217, 0.85);

  --text-primary: #2d261e;
  --text-secondary: #4a3f32;
  --text-muted: #736452;
  --text-inverse: #fbf0d9;

  --accent-primary: #965318;
  --accent-secondary: #794212;
  --accent-hover: #67370e;
  --accent-glow: rgba(150, 83, 24, 0.15);

  --border-subtle: #dfcca0;
  --border-focus: #965318;
  --ruler-bg: rgba(150, 83, 24, 0.2);
  --ruler-border: #965318;
}

/* --- Theme: Pastel Calming Green / Low Sensory Mode --- */
[data-theme="calm-green"] {
  --bg-primary: #ecfdf5;
  --bg-secondary: #d1fae5;
  --bg-tertiary: #a7f3d0;
  --bg-card: rgba(209, 250, 229, 0.85);
  --bg-card-hover: #e6fffa;
  --bg-overlay: rgba(236, 253, 245, 0.85);

  --text-primary: #064e3b;
  --text-secondary: #065f46;
  --text-muted: #047857;
  --text-inverse: #ecfdf5;

  --accent-primary: #059669;
  --accent-secondary: #0d9488;
  --accent-hover: #047857;
  --accent-glow: rgba(5, 150, 105, 0.2);

  --border-subtle: #a7f3d0;
  --border-focus: #059669;
}

/* --- Theme: Pastel Calming Blue / Serenity Mode --- */
[data-theme="calm-blue"] {
  --bg-primary: #f0f9ff;
  --bg-secondary: #e0f2fe;
  --bg-tertiary: #bae6fd;
  --bg-card: rgba(224, 242, 254, 0.85);
  --bg-card-hover: #eaf6fe;
  --bg-overlay: rgba(240, 249, 255, 0.85);

  --text-primary: #0c4a6e;
  --text-secondary: #0369a1;
  --text-muted: #0284c7;
  --text-inverse: #f0f9ff;

  --accent-primary: #0284c7;
  --accent-secondary: #3b82f6;
  --accent-hover: #0369a1;
  --accent-glow: rgba(2, 132, 199, 0.2);

  --border-subtle: #bae6fd;
  --border-focus: #0284c7;
}

/* --- Theme: High-Contrast Monochromatic (WCAG AAA 7:1+) --- */
[data-theme="high-contrast"] {
  --bg-primary: #000000;
  --bg-secondary: #000000;
  --bg-tertiary: #18181b;
  --bg-card: #000000;
  --bg-card-hover: #18181b;
  --bg-overlay: rgba(0, 0, 0, 0.95);

  --text-primary: #ffffff;
  --text-secondary: #ffff55;
  --text-muted: #e4e4e7;
  --text-inverse: #000000;

  --accent-primary: #ffff00;
  --accent-secondary: #00ffff;
  --accent-hover: #fef08a;
  --accent-glow: rgba(255, 255, 0, 0.4);

  --border-subtle: #ffffff;
  --border-focus: #ffff00;
  --focus-outline-width: 4px;
}

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

html {
  font-size: var(--base-font-size);
  line-height: var(--font-line-height);
  letter-spacing: var(--font-letter-spacing);
  word-spacing: var(--font-word-spacing);
  font-family: var(--font-family-base);
  color: var(--text-primary);
  background-color: var(--bg-primary);
  scroll-behavior: smooth;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  position: relative;
  overflow-x: hidden;
  transition: background-color var(--transition-speed) var(--transition-fn),
              color var(--transition-speed) var(--transition-fn);
}

/* Ambient Aurora Mesh Background Layer */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  background-image: 
    radial-gradient(at 15% 15%, rgba(56, 189, 248, 0.12) 0px, transparent 45%),
    radial-gradient(at 85% 20%, rgba(129, 140, 248, 0.14) 0px, transparent 50%),
    radial-gradient(at 50% 65%, rgba(52, 211, 153, 0.10) 0px, transparent 45%),
    radial-gradient(at 80% 85%, rgba(244, 114, 182, 0.10) 0px, transparent 50%);
  background-attachment: fixed;
  opacity: 0.9;
}

[data-theme="light"] body::before,
[data-theme="light"]::before {
  background-image: 
    radial-gradient(at 15% 15%, rgba(2, 132, 199, 0.08) 0px, transparent 45%),
    radial-gradient(at 85% 20%, rgba(99, 102, 241, 0.08) 0px, transparent 50%),
    radial-gradient(at 50% 75%, rgba(16, 185, 129, 0.06) 0px, transparent 45%);
}

[data-theme="sepia"] body::before,
[data-theme="sepia"]::before {
  background-image: 
    radial-gradient(at 15% 15%, rgba(245, 158, 11, 0.12) 0px, transparent 45%),
    radial-gradient(at 85% 25%, rgba(217, 119, 6, 0.10) 0px, transparent 50%),
    radial-gradient(at 50% 80%, rgba(180, 83, 9, 0.08) 0px, transparent 45%);
}

[data-theme="calm-green"] body::before,
[data-theme="calm-green"]::before {
  background-image: 
    radial-gradient(at 15% 15%, rgba(16, 185, 129, 0.14) 0px, transparent 45%),
    radial-gradient(at 85% 25%, rgba(13, 148, 136, 0.14) 0px, transparent 50%),
    radial-gradient(at 50% 75%, rgba(5, 150, 105, 0.10) 0px, transparent 45%);
}

[data-theme="calm-blue"] body::before,
[data-theme="calm-blue"]::before {
  background-image: 
    radial-gradient(at 15% 15%, rgba(2, 132, 199, 0.15) 0px, transparent 45%),
    radial-gradient(at 85% 25%, rgba(59, 130, 246, 0.15) 0px, transparent 50%),
    radial-gradient(at 50% 75%, rgba(99, 102, 241, 0.12) 0px, transparent 45%);
}

[data-theme="high-contrast"] body::before,
[data-theme="high-contrast"]::before {
  display: none;
}

/* Font classes */
body[data-font="opendyslexic"] {
  font-family: var(--font-family-opendyslexic);
}

body[data-font="atkinson"] {
  font-family: var(--font-family-atkinson);
}

body[data-font="sans"] {
  font-family: var(--font-family-sans);
}

body[data-font="lexend"] {
  font-family: var(--font-family-base);
}

/* Accessible Focus Rings */
:focus-visible {
  outline: var(--focus-outline-width) solid var(--border-focus) !important;
  outline-offset: var(--focus-outline-offset) !important;
  border-radius: var(--radius-sm);
  box-shadow: 0 0 0 4px var(--accent-glow) !important;
}

/* Skip to main content link (WCAG 2.4.1) */
.skip-link {
  position: absolute;
  top: -80px;
  left: 20px;
  background: var(--accent-primary);
  color: var(--text-inverse);
  padding: 12px 24px;
  font-weight: 700;
  border-radius: var(--radius-sm);
  z-index: 10000;
  transition: top 0.2s ease-in-out;
  text-decoration: none;
  box-shadow: var(--shadow-lg);
}

.skip-link:focus {
  top: 20px;
}

/* Live region for screen reader announcements */
.sr-only {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

/* Reduced Motion Compliance */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

body.reduced-motion *, body.reduced-motion *::before, body.reduced-motion *::after {
  animation-duration: 0.01ms !important;
  animation-iteration-count: 1 !important;
  transition-duration: 0.01ms !important;
  scroll-behavior: auto !important;
}