:root {
  --color-ink: #111111;
  --color-paper: #ffffff;
  --color-surface: #f5f5f7;
  --color-border: #e5e5e5;
  --color-muted: #666666;
  --color-soft: #8a8a8a;
  --font-sans: Inter, "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --font-mono: "SFMono-Regular", Consolas, monospace;
  --space-1: 8px; --space-2: 16px; --space-3: 24px; --space-4: 32px;
  --space-5: 48px; --space-6: 64px; --space-7: 96px; --space-8: 128px;
  --radius-button: 12px; --radius-card: 24px; --radius-input: 20px;
  --shadow-soft: 0 10px 30px rgba(0, 0, 0, 0.05);
  --container: 1160px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--color-paper); color: var(--color-ink); font-family: var(--font-sans); -webkit-font-smoothing: antialiased; }
h1, h2, h3, p { margin-top: 0; }
a { color: inherit; text-decoration: none; }
button, input, textarea { font: inherit; }
button, a, input, textarea, select { -webkit-tap-highlight-color: transparent; }
:focus-visible { outline: 3px solid var(--color-accent, #2563eb); outline-offset: 3px; box-shadow: var(--focus-ring, 0 0 0 4px rgba(37,99,235,.2)); }