:root {
    --color-text-primary: #1a1a1a;
    --color-text-secondary: #555;
    --color-text-tertiary: #999;
    --color-background-primary: #ffffff;
    --color-background-secondary: #f4f4f2;
    --color-background-tertiary: #eaeae8;
    --color-border-tertiary: rgba(0,0,0,0.12);
    --color-border-secondary: rgba(0,0,0,0.25);
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'Cascadia Code', 'Consolas', 'SF Mono', monospace;
    --border-radius-md: 8px;
    --border-radius-lg: 12px;
    --border-radius-xl: 16px;
  }
  *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
  html { scroll-behavior: smooth; }
  body { font-family: var(--font-sans); background: #f9f9f8; color: var(--color-text-primary); min-height: 100vh; }
  button { font-family: inherit; cursor: pointer; }
  .sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }