/* roulang page: index */
:root {
      --primary: #00F0C8;
      --primary-glow: rgba(0, 240, 200, 0.5);
      --secondary: #7B2FFF;
      --bg-deep: #0B0C10;
      --bg-secondary: #15171E;
      --glass-bg: rgba(255, 255, 255, 0.03);
      --glass-border: rgba(255, 255, 255, 0.06);
      --text-white: #FFFFFF;
      --text-body: #B0B8C5;
      --text-muted: #6B7280;
      --radius-card: 16px;
      --radius-button: 50px;
      --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.4);
      --transition-smooth: all 0.3s ease;
      --font-title: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
      --font-body: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
      --font-number: 'Inter', 'DIN Alternate', 'PingFang SC', sans-serif;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      background-color: var(--bg-deep);
      color: var(--text-body);
      font-family: var(--font-body);
      line-height: 1.6;
      font-weight: 400;
      overflow-x: hidden;
    }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 1.5rem;
    }

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

    a {
      text-decoration: none;
      color: inherit;
    }

    /* 导航 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 50;
      background: rgba(11, 12, 16, 0.75);
      backdrop-filter: blur(24px) saturate(180%);
      -webkit-backdrop-filter: blur(24px) saturate(180%);
      border-bottom: 1px solid rgba(255, 255, 255, 0.05);
      height: 72px;
      display: flex;
      align-items: center;
    }

    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 1.5rem;
    }

    .logo {
      font-family: var(--font-title);
      font-weight: 800;
      font-size: 1.5rem;
      color: var(--text-white);
      display: flex;
      align-items: center;
      gap: 0.25rem;
    }

    .logo span {
      color: var(--primary);
      text-decoration: underline;
      text-underline-offset: 4px;
    }

    .nav-menu {
      display: flex;
      gap: 2rem;
      align-items: center;
    }

    .nav-link {
      color: var(--text-body);
      font-weight: 500;
      font-size: 0.95rem;
      padding: 0.5rem 0.25rem;
      position: relative;
      transition: color 0.3s;
    }

    .nav-link::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background-color: var(--primary);
      transition: width 0.3s ease;
    }

    .nav-link:hover,
    .nav-link.active {
      color: var(--text-white);
    }

    .nav-link:hover::after,
    .nav-link.active::after {
      width: 100%;
    }

    .btn-nav {
      background: var(--primary);
      color: var(--bg-deep);
      font-weight: 700;
      padding: 0.5rem 1.5rem;
      border-radius: var(--radius-button);
      font-size: 0.9rem;
      box-shadow: 0 0 15px var(--primary-glow);
      transition: var(--transition-smooth);
    }

    .btn-nav:hover {
      background: #1AFFD9;
      box-shadow: 0 0 25px var(--primary-glow);
      transform: scale(1.03);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      cursor: pointer;
      gap: 5px;
    }

    .hamburger span {
      width: 25px;
      height: 2px;
      background: white;
      transition: 0.3s;
    }

    .mobile-menu {
      display: none;
    }

    /* 按钮全局 */
    .btn-primary {
      background: var(--primary);
      color: var(--bg-deep);
      font-weight: 700;
      padding: 0.75rem 2rem;
      border-radius: var(--radius-button);
      box-shadow: 0 0 20px rgba(0, 240, 200, 0.4);
      transition: var(--transition-smooth);
      border: none;
      cursor: pointer;
      font-size: 1rem;
    }

    .btn-primary:hover {
      background: #1AFFD9;
      box-shadow: 0 0 35px rgba(0, 240, 200, 0.7);
      transform: scale(1.03);
    }

    .btn-ghost {
      background: transparent;
      border: 1.5px solid rgba(255,255,255,0.25);
      color: white;
      font-weight: 600;
      padding: 0.75rem 2rem;
      border-radius: var(--radius-button);
      transition: var(--transition-smooth);
      cursor: pointer;
    }

    .btn-ghost:hover {
      border-color: var(--primary);
      color: var(--primary);
      background: rgba(0,240,200,0.05);
    }

    .section-title {
      font-family: var(--font-title);
      font-weight: 700;
      font-size: 2.5rem;
      color: var(--text-white);
      margin-bottom: 1rem;
      line-height: 1.2;
    }

    .section-subtitle {
      color: var(--text-body);
      font-size: 1.125rem;
      max-width: 700px;
      margin: 0 auto 2.5rem;
    }

    .glass-card {
      background: var(--glass-bg);
      backdrop-filter: blur(20px) saturate(180%);
      -webkit-backdrop-filter: blur(20px) saturate(180%);
      border: 1px solid var(--glass-border);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      transition: var(--transition-smooth);
    }

    .glass-card:hover {
      border-color: rgba(0,240,200,0.3);
      box-shadow: 0 0 30px rgba(0,240,200,0.15);
      transform: translateY(-4px);
    }

    footer {
      background: #06070A;
      color: var(--text-muted);
      padding: 3rem 0;
    }

.mobile-menu {
      display: none;
      position: fixed; top: 72px; left: 0; width: 100%; height: calc(100vh - 72px);
      background: rgba(11,12,16,0.95); backdrop-filter: blur(30px); flex-direction: column;
      justify-content: center; align-items: center; gap: 2rem; z-index: 40;
    }
    .mobile-menu.active { display: flex; }
    .mobile-menu a { color: white; font-size: 1.5rem; font-weight: 500; }
    @media (max-width: 768px) {
      .nav-menu { display: none; }
      .hamburger { display: flex; }
      h1 { font-size: 2.2rem !important; }
      .section-title { font-size: 2rem !important; }
    }
    @media (min-width: 769px) {
      .mobile-menu { display: none !important; }
    }