/* Ocean: The Learning Depth — Design Tokens (Human-Designed Editorial Theme) */

:root {
  /* ─── Typography & Fonts ───────────────────────────────────────── */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-display: 'Plus Jakarta Sans', var(--font-sans);
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  --text-xs: 0.75rem;
  --text-sm: 0.8125rem;
  --text-base: 0.9375rem;
  --text-lg: 1.0625rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;

  --leading-tight: 1.25;
  --leading-normal: 1.6;
  --leading-relaxed: 1.72;

  --weight-normal: 400;
  --weight-medium: 500;
  --weight-semibold: 600;
  --weight-bold: 700;

  /* ─── Layout Dimensions ────────────────────────────────────────── */
  --sidebar-w: 260px;
  --header-height: 54px;
  --toc-width: 220px;

  /* ─── Spacing Scale ────────────────────────────────────────────── */
  --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;

  /* ─── Radii ───────────────────────────────────────────────────── */
  --radius-xs: 4px;
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --radius-xl: 16px;
  --radius-2xl: 20px;
  --radius-full: 9999px;

  /* ─── Transitions ─────────────────────────────────────────────── */
  --transition-fast: 120ms ease;
  --transition-base: 200ms cubic-bezier(0.16, 1, 0.3, 1);
  --transition-slow: 350ms cubic-bezier(0.16, 1, 0.3, 1);

  /* ─── Dark Mode (Default / Pure Obsidian Charcoal) ────────────── */
  --bg: #09090B;
  --surface: #121215;
  --surface-1: #121215;
  --surface-2: #18181C;
  --surface-3: #222227;
  --surface-elevated: #16161A;
  --border: rgba(255, 255, 255, 0.08);
  --border-subtle: rgba(255, 255, 255, 0.04);
  --border-focus: rgba(59, 130, 246, 0.5);

  --text: #F4F4F5;
  --text-secondary: #A1A1AA;
  --text-muted: #71717A;
  --text-dim: #52525B;

  --sidebar-bg: #0D0D10;
  --pill-bg: #121215;
  --pill-border: rgba(255, 255, 255, 0.1);
  --pill-hover: #18181C;
  --pill-focus: #222227;
  --item-hover: rgba(255, 255, 255, 0.04);
  --item-active: rgba(255, 255, 255, 0.08);
  --bg-surface: #121215;
  --bg-surface-2: #18181C;

  /* Docked Scrim fading seamlessly into obsidian background */
  --docked-scrim: linear-gradient(180deg, rgba(9, 9, 11, 0) 0%, rgba(9, 9, 11, 0.85) 45%, #09090B 100%);

  /* Academic Formula Styling (Donald Knuth / LaTeX Publication standard) */
  --formula-bg: #111114;
  --formula-border: rgba(255, 255, 255, 0.08);
  --formula-text: #F4F4F5;

  /* Semantic Editorial Accents */
  --blue: #3B82F6;
  --blue-dim: rgba(59, 130, 246, 0.1);
  --blue-border: rgba(59, 130, 246, 0.22);

  --green: #10B981;
  --green-dim: rgba(16, 185, 129, 0.1);
  --green-border: rgba(16, 185, 129, 0.22);

  --amber: #F59E0B;
  --amber-dim: rgba(245, 158, 11, 0.1);
  --amber-border: rgba(245, 158, 11, 0.22);

  --red: #F43F5E;
  --red-dim: rgba(244, 63, 94, 0.1);
  --red-border: rgba(244, 63, 94, 0.22);

  --purple: #8B5CF6;
  --purple-dim: rgba(139, 92, 246, 0.1);
  --purple-border: rgba(139, 92, 246, 0.22);

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 14px rgba(0, 0, 0, 0.45);
  --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.55);
  --card-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.5), 0 2px 6px -1px rgba(0, 0, 0, 0.3);
  --card-hover-shadow: 0 16px 36px -4px rgba(0, 0, 0, 0.7), 0 4px 12px -2px rgba(0, 0, 0, 0.4);
}

/* ─── Light Mode (Clean Modern Studio / Screenshot Standard) ───── */
[data-theme="light"] {
  --bg: #FFFFFF;
  --surface: #FFFFFF;
  --surface-1: #FFFFFF;
  --surface-2: #F9FAFB;
  --surface-3: #F3F4F6;
  --surface-elevated: #FFFFFF;
  --border: #E5E7EB;
  --border-subtle: #F3F4F6;
  --border-focus: #9CA3AF;

  --text: #0F172A;
  --text-secondary: #475569;
  --text-muted: #94A3B8;
  --text-dim: #94A3B8;

  --sidebar-bg: #F9FAFB;
  --pill-bg: #FFFFFF;
  --pill-border: #E5E7EB;
  --pill-hover: #FFFFFF;
  --pill-focus: #94A3B8;
  --item-hover: #F3F4F6;
  --item-active: #E5E7EB;
  --bg-surface: #FFFFFF;
  --bg-surface-2: #F9FAFB;

  /* Seamless white gradient fade for docked chat input */
  --docked-scrim: linear-gradient(180deg, rgba(255, 255, 255, 0) 0%, rgba(255, 255, 255, 0.95) 45%, #FFFFFF 100%);

  /* Academic Formula Styling in Light Mode */
  --formula-bg: #F8FAFC;
  --formula-border: #E2E8F0;
  --formula-text: #0F172A;

  /* Semantic Editorial Accents */
  --blue: #2563EB;
  --blue-dim: rgba(37, 99, 235, 0.08);
  --blue-border: rgba(37, 99, 235, 0.2);

  --green: #10B981;
  --green-dim: rgba(16, 185, 129, 0.08);
  --green-border: rgba(16, 185, 129, 0.2);

  --amber: #F59E0B;
  --amber-dim: rgba(245, 158, 11, 0.08);
  --amber-border: rgba(245, 158, 11, 0.2);

  --red: #EF4444;
  --red-dim: rgba(239, 68, 68, 0.08);
  --red-border: rgba(239, 68, 68, 0.2);

  --purple: #8B5CF6;
  --purple-dim: rgba(139, 92, 246, 0.08);
  --purple-border: rgba(139, 92, 246, 0.2);

  /* Modern soft shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.04);
  --shadow-md: 0 4px 14px rgba(0, 0, 0, 0.05);
  --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.08);
  --card-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.05), 0 2px 6px -1px rgba(0, 0, 0, 0.02);
  --card-hover-shadow: 0 12px 28px -4px rgba(0, 0, 0, 0.08), 0 3px 10px -2px rgba(0, 0, 0, 0.03);
}

@media (prefers-reduced-motion: reduce) {
  :root {
    --transition-fast: 0ms;
    --transition-base: 0ms;
    --transition-slow: 0ms;
  }
}