/* Math Insight — Design Tokens */
:root {
  /* Brand — academic burgundy */
  --color-brand: #6b1d2a;
  --color-brand-dark: #4a121c;
  --color-brand-light: #8b2e3c;
  --color-accent: #c4a35a;
  --color-accent-hover: #d4b56a;

  /* Neutrals */
  --color-bg: #f7f5f2;
  --color-bg-elevated: #ffffff;
  --color-bg-muted: #efeae4;
  --color-ink: #1c1917;
  --color-ink-muted: #57534e;
  --color-border: #e7e0d6;
  --color-success: #2f6b4f;
  --color-error: #9b2c2c;

  /* Typography */
  --font-display: "Noto Serif TC", "Source Serif 4", Georgia, serif;
  --font-body: "Noto Sans TC", "Source Sans 3", system-ui, sans-serif;
  --fs-xs: 0.8125rem;
  --fs-sm: 0.9375rem;
  --fs-base: 1.0625rem;
  --fs-lg: 1.25rem;
  --fs-xl: 1.5rem;
  --fs-2xl: clamp(1.75rem, 2.5vw, 2.25rem);
  --fs-3xl: clamp(2.25rem, 4vw, 3.25rem);
  --fs-hero: clamp(2.5rem, 6vw, 4rem);
  --lh-tight: 1.25;
  --lh-body: 1.7;

  /* Spacing */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 4rem;
  --space-9: 6rem;
  --container: 72rem;
  --container-narrow: 48rem;

  /* Layout */
  --header-h: 4.25rem;
  --radius: 0.25rem;
  --radius-lg: 0.5rem;
  --shadow-sm: 0 1px 2px rgba(28, 25, 23, 0.06);
  --shadow-md: 0 8px 24px rgba(28, 25, 23, 0.08);
  --transition: 0.25s ease;
  --z-header: 1000;
  --z-overlay: 1100;
  --z-top: 1200;
}

@media (max-width: 768px) {
  :root {
    --header-h: 3.75rem;
  }
}