:root { --primary: #1D7BFF; --primary-light: #E8F1FF; --text-main: #1F2937; --text-muted: #6B7280; --bg-body: #F8FAFC; --bg-card: #FFFFFF; --border-color: #E2E8F0; --radius: 8px; }
    * { box-sizing: border-box; margin: 0; padding: 0; }
    body { font-family: "PingFang SC", "Noto Sans SC", sans-serif; background-color: var(--bg-body); color: var(--text-main); line-height: 1.6; font-size: 14px; }
    a { color: inherit; text-decoration: none; }
    a:hover { color: var(--primary); }
    .container { max-width: 1200px; margin: 0 auto; padding: 0 16px; }
    
    .header-wrapper { padding: 16px 0; }
    .header-bar { background: var(--bg-card); border-radius: 12px; padding: 12px 24px; display: flex; align-items: center; justify-content: space-between; box-shadow: 0 2px 12px rgba(0,0,0,0.04); border: 1px solid var(--border-color); }
    .logo { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 20px; color: var(--primary); }
    .logo img { max-height: 36px; }
    .nav-desktop { display: flex; align-items: center; gap: 20px; }
    .nav-desktop a { font-size: 15px; font-weight: 600; padding: 6px 12px; border-radius: 6px; }
    .menu-btn { display: none; background: none; border: none; cursor: pointer; padding: 6px; }
    .menu-btn span { display: block; width: 22px; height: 2px; background: var(--text-main); margin: 4px 0; }

    .drawer-overlay { position: fixed; inset: 0; background: rgba(0,0,0,0.5); z-index: 998; opacity: 0; visibility: hidden; transition: 0.3s; }
    .drawer-overlay.active { opacity: 1; visibility: visible; }
    .drawer { position: fixed; top: 0; left: -280px; width: 280px; height: 100%; background: #fff; z-index: 999; transition: 0.3s; padding: 20px; }
    .drawer.active { left: 0; }
    .drawer-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 20px; padding-bottom: 10px; border-bottom: 1px solid var(--border-color); }
    .drawer-nav { display: flex; flex-direction: column; gap: 10px; }
    .drawer-nav a { padding: 10px; border-radius: 6px; font-weight: 500; }

    .about-card { background: var(--bg-card); border: 1px solid var(--border-color); border-radius: var(--radius); padding: 32px; margin: 20px 0; }
    .about-title { font-size: 24px; font-weight: 800; color: var(--primary); margin-bottom: 16px; text-align: center; }
    .about-content p { margin-bottom: 16px; font-size: 15px; color: #374151; text-indent: 2em; }
    .feature-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; margin-top: 30px; }
    .feat-box { background: #F8FAFC; border: 1px solid var(--border-color); border-radius: 8px; padding: 20px; text-align: center; }
    .feat-box h4 { font-size: 16px; color: var(--primary); margin-bottom: 8px; }

    footer { background: #1E293B; color: #94A3B8; padding: 40px 0 20px; font-size: 13px; margin-top: 40px; }
    .footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1.5fr; gap: 30px; margin-bottom: 30px; }
    .footer-col h4 { color: #F8FAFC; font-size: 15px; margin-bottom: 14px; }
    .footer-col p { line-height: 1.6; margin-bottom: 10px; }
    .footer-nav { display: flex; flex-direction: column; gap: 8px; }
    .friend-links { border-top: 1px solid #334155; padding-top: 16px; margin-top: 20px; }
    .friend-title { font-weight: 700; color: #CBD5E1; margin-bottom: 8px; }
    .friend-content { display: flex; flex-wrap: wrap; gap: 12px; }
    .copyright-bar { text-align: center; border-top: 1px solid #334155; padding-top: 16px; font-size: 12px; }

    @media (max-width: 768px) {
      .nav-desktop { display: none; }
      .menu-btn { display: block; }
      .feature-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr; }
    }