:root {
      --bg: #ffffff;
      --text: #222;
      --accent: #0078ff;
      --muted: #666;
    }
    @media (prefers-color-scheme: dark) {
      :root {
        --bg: #1c1c1e;
        --text: #f2f2f7;
        --muted: #a0a0a5;
      }
    }

    body {
      margin: 0;
      padding: 0;
      font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
      background: var(--bg);
      color: var(--text);
      line-height: 1.6;
    }

    header {
      background: var(--accent);
      color: #fff;
      padding: 2.5rem 1rem;
      text-align: center;
    }

    header h1 {
      margin: 0;
      font-size: 1.8rem;
    }

    main {
      max-width: 800px;
      margin: 0 auto;
      padding: 2rem 1.5rem;
    }

    h2 {
      margin-top: 2rem;
      color: var(--accent);
      font-size: 1.3rem;
    }

    a {
      color: var(--accent);
      text-decoration: none;
    }
    a:hover { text-decoration: underline; }

    footer {
      text-align: center;
      font-size: 0.9rem;
      color: var(--muted);
      padding: 2rem 1rem;
      border-top: 1px solid rgba(0,0,0,0.1);
    }
    @media (prefers-color-scheme: dark) {
      footer { border-color: rgba(255,255,255,0.1); }
    }