:root {
  /* Colors */
  --color-bg: #fafaf9;
  --color-text: #1a1a1a;
  --color-text-muted: #6b6b6b;
  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-border: #e5e5e5;
  --color-surface: #ffffff;
  --color-ad-bg: #f4f4f3;
  --color-backdrop: rgba(0, 0, 0, 0.4);

  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen,
    Ubuntu, Cantarell, "Helvetica Neue", sans-serif;
  --font-family-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas,
    monospace;

  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.5rem;
  --font-size-2xl: 2rem;

  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;

  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;

  /* Spacing (4px base) */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3rem;

  /* Layout */
  --content-max-width: 640px;
  --pane-width-desktop: 420px;

  /* Radius & shadow */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --shadow-pane: -4px 0 24px rgba(0, 0, 0, 0.12);
}