/* roulang page: index */
:root {
      --primary-deep: #0A0E27;
      --accent-cyan: #00F0FF;
      --accent-red: #FF4655;
      --card-bg: #141832;
      --bg-dark: #0F1330;
      --border-light: rgba(0,240,255,0.08);
      --text-primary: #FFFFFF;
      --text-secondary: #E0E6FF;
      --text-body: #B0B8D0;
      --text-muted: #8A92B0;
      --font-body: 'PingFang SC', 'Microsoft YaHei', 'Inter', system-ui, -apple-system, sans-serif;
      --font-number: 'Inter', 'Roboto', system-ui, sans-serif;
      --radius-card: 12px;
      --radius-btn: 8px;
      --max-width: 1280px;
      --gap-section: 120px;
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    body {
      font-family: var(--font-body);
      background-color: var(--primary-deep);
      color: var(--text-body);
      line-height: 1.8;
      letter-spacing: 0.02em;
      -webkit-font-smoothing: antialiased;
    }

    a, button, input, textarea {
      font-family: inherit;
    }

    img {
      max-width: 100%;
      display: block;
      height: auto;
    }

    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 导航栏 */
    header.nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: rgba(10,14,39,0.85);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(0,240,255,0.1);
      z-index: 50;
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .nav-container {
      width: min(100%, var(--max-width));
      margin: 0 auto;
      padding: 0 24px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
    }

    .logo-area {
      display: flex;
      align-items: center;
      gap: 6px;
      text-decoration: none;
      font-weight: 700;
      font-size: 1.35rem;
      letter-spacing: -0.3px;
      color: #fff;
    }
    .logo-accent {
      color: var(--accent-cyan);
      margin-right: 4px;
      font-weight: 600;
      transform: rotate(20deg);
      font-size: 1.1rem;
    }
    .logo-sub {
      font-size: 0.7rem;
      font-weight: 400;
      letter-spacing: 0.16em;
      color: var(--accent-cyan);
      margin-left: 4px;
      text-transform: uppercase;
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 2rem;
      list-style: none;
    }

    .nav-links a {
      color: var(--text-muted);
      text-decoration: none;
      font-weight: 500;
      font-size: 0.95rem;
      position: relative;
      padding: 6px 0;
      transition: color 0.3s ease;
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--accent-cyan);
      transition: width 0.3s ease;
    }

    .nav-links a:hover, .nav-links a.active {
      color: var(--accent-cyan);
    }
    .nav-links a:hover::after, .nav-links a.active::after {
      width: 100%;
    }

    .cta-nav {
      background: var(--accent-cyan);
      color: var(--primary-deep);
      font-weight: 700;
      padding: 10px 26px;
      border-radius: var(--radius-btn);
      text-decoration: none;
      transition: all 0.3s ease;
      box-shadow: 0 0 14px rgba(0,240,255,0.4);
      font-size: 0.9rem;
    }
    .cta-nav:hover {
      box-shadow: 0 0 28px rgba(0,240,255,0.7);
      transform: scale(1.03);
      background: #4af5ff;
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--accent-cyan);
      transition: 0.3s;
    }

    @media (max-width: 768px) {
      .nav-links, .cta-nav.desktop-only {
        display: none;
      }
      .hamburger {
        display: flex;
      }
    }

    /* 抽屉菜单 */
    .drawer {
      position: fixed;
      top: 0;
      right: -100%;
      width: 280px;
      height: 100vh;
      background: var(--primary-deep);
      backdrop-filter: blur(30px);
      padding: 2rem;
      display: flex;
      flex-direction: column;
      gap: 2rem;
      z-index: 100;
      transition: right 0.3s ease;
      border-left: 1px solid rgba(0,240,255,0.15);
    }
    .drawer.open {
      right: 0;
    }
    .drawer a {
      color: white;
      font-size: 1.2rem;
      text-decoration: none;
      padding: 12px 0;
      border-bottom: 1px solid rgba(255,255,255,0.1);
    }

    section {
      padding: calc(var(--gap-section)/1.5) 0;
    }
    h1 { font-size: 3.2rem; font-weight: 700; line-height: 1.2; letter-spacing: -0.02em; color: #fff; }
    h2 { font-size: 2.2rem; font-weight: 700; color: #fff; margin-bottom: 8px; display: inline-block; border-bottom: 4px solid var(--accent-cyan); padding-bottom: 8px; }
    h3 { font-size: 1.4rem; font-weight: 600; color: var(--text-secondary); }

    /* hero */
    #hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      position: relative;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      background-blend-mode: overlay;
      background-color: rgba(10,14,39,0.65);
    }
    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 780px;
    }
    .btn-primary {
      background: var(--accent-cyan);
      color: #0A0E27;
      font-weight: 700;
      padding: 14px 34px;
      border-radius: var(--radius-btn);
      text-decoration: none;
      transition: 0.3s ease;
      box-shadow: 0 0 18px rgba(0,240,255,0.5);
    }
    .btn-secondary {
      border: 1.8px solid var(--accent-cyan);
      color: var(--accent-cyan);
      background: transparent;
      padding: 14px 34px;
      border-radius: var(--radius-btn);
      text-decoration: none;
      margin-left: 12px;
    }

    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 24px;
      margin-top: 2.5rem;
    }
    .high-light-card {
      background: var(--card-bg);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-card);
      padding: 28px 16px;
      text-align: center;
      transition: 0.3s;
    }
    .high-light-card:hover {
      border-color: var(--accent-cyan);
      transform: translateY(-5px);
      box-shadow: 0 16px 40px rgba(0,0,0,0.6);
    }

    .comparison-wrapper {
      display: flex;
      align-items: stretch;
      gap: 2rem;
    }
    .vs-badge {
      background: linear-gradient(145deg, var(--accent-cyan), #005566);
      border-radius: 50%;
      width: 58px;
      height: 58px;
      display: grid;
      place-content: center;
      font-weight: bold;
      color: white;
    }

    .faq-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 20px;
    }
    footer {
      background: #060918;
      border-top: 2px solid var(--accent-cyan);
    }
    @media (max-width: 768px) {
      h1 { font-size: 2.4rem; }
      .grid-4 { grid-template-columns: repeat(2,1fr);}
      .comparison-wrapper { flex-direction: column; }
      .faq-grid { grid-template-columns: 1fr; }
    }
    button, .btn-style { cursor: pointer; }