/* roulang page: index */
:root {
      --primary: #FF4D00;
      --primary-deep: #CC3E00;
      --accent: #00F0FF;
      --bg-dark: #1A1A1A;
      --bg-card: #242424;
      --bg-footer: #111111;
      --text-bright: #F2F2F2;
      --text-muted: #B0B0B0;
      --border: #333333;
      --radius: 8px;
      --transition: 0.3s ease;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      background-color: var(--bg-dark);
      color: var(--text-bright);
      line-height: 1.7;
      scroll-behavior: smooth;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 40px;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    button {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
    }
    h1, h2, h3 {
      font-weight: 700;
    }
    h2 {
      display: flex;
      align-items: center;
      font-size: clamp(2rem, 5vw, 2.8rem);
      margin-bottom: 1.5rem;
      position: relative;
      letter-spacing: -0.5px;
    }
    h2::before {
      content: '';
      display: inline-block;
      width: 5px;
      height: 32px;
      background: var(--primary);
      margin-right: 16px;
      border-radius: 4px;
    }
    section {
      padding: 90px 0;
    }
    /* 导航 */
    .main-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(26, 26, 26, 0.9);
      backdrop-filter: blur(12px);
      z-index: 1000;
      border-bottom: 1px solid rgba(255, 77, 0, 0.15);
      padding: 0;
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 70px;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 40px;
    }
    .logo {
      font-size: 1.8rem;
      font-weight: 800;
      color: var(--primary);
      letter-spacing: 1px;
      background: linear-gradient(to right, #FF4D00, #FF8C00);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .nav-menu {
      display: flex;
      gap: 2.5rem;
      align-items: center;
    }
    .nav-link {
      font-weight: 700;
      font-size: 0.95rem;
      color: var(--text-bright);
      text-transform: uppercase;
      transition: color var(--transition);
      position: relative;
      padding-bottom: 6px;
    }
    .nav-link:hover {
      color: var(--primary);
    }
    .nav-link.active {
      color: var(--primary);
    }
    .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      right: 0;
      height: 3px;
      background: var(--accent);
      border-radius: 2px;
    }
    .menu-toggle {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
    }
    .menu-toggle span {
      width: 28px;
      height: 3px;
      background: var(--text-bright);
      border-radius: 2px;
      transition: all 0.3s;
    }
    /* 按钮 */
    .btn-primary {
      background: var(--primary);
      color: #FFF;
      padding: 14px 32px;
      border-radius: 4px;
      font-weight: 700;
      font-size: 1rem;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: background 0.2s, box-shadow 0.2s;
      text-transform: uppercase;
      letter-spacing: 0.5px;
    }
    .btn-primary:hover {
      background: var(--primary-deep);
      box-shadow: 0 0 20px rgba(255, 77, 0, 0.6);
    }
    .btn-ghost {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 12px 28px;
      border-radius: 4px;
      font-weight: 700;
      transition: all 0.25s;
      text-transform: uppercase;
    }
    .btn-ghost:hover {
      background: var(--primary);
      color: white;
      box-shadow: 0 0 16px rgba(255,77,0,0.4);
    }
    /* Hero 背景图采用back-2 */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: linear-gradient(135deg, rgba(26,26,26,0.7) 0%, rgba(26,26,26,0.2) 100%), url('/assets/images/backpic/back-2.webp') center/cover no-repeat;
      background-attachment: fixed;
      position: relative;
    }
    .hero-content {
      text-align: left;
      max-width: 800px;
    }
    .hero h1 {
      font-size: clamp(3.5rem, 8vw, 5.5rem);
      font-weight: 900;
      background: linear-gradient(to right, #FF4D00, #FF8C00);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      line-height: 1.1;
      margin-bottom: 1.5rem;
      letter-spacing: -1px;
    }
    .hero-sub {
      font-size: 1.2rem;
      color: var(--text-muted);
      margin-bottom: 2.5rem;
    }
    .hero-buttons {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }
    /* 卡片 */
    .card-grid {
      display: grid;
      gap: 30px;
      margin-top: 2rem;
    }
    .card {
      background: var(--bg-card);
      border: 1px solid var(--border);
      border-radius: var(--radius);
      padding: 35px 25px;
      transition: all var(--transition);
      box-shadow: 0 4px 12px rgba(255, 77, 0, 0.08);
    }
    .card:hover {
      transform: translateY(-5px);
      border-color: var(--primary);
      box-shadow: 0 12px 24px rgba(255, 77, 0, 0.15);
    }
    .card h3 {
      font-size: 1.6rem;
      margin-bottom: 1rem;
      color: white;
    }
    .stats-block {
      display: flex;
      flex-wrap: wrap;
      gap: 2rem 4rem;
      justify-content: center;
      margin: 3rem 0;
    }
    .stat-item {
      text-align: center;
    }
    .stat-number {
      font-size: 3rem;
      font-weight: 900;
      color: var(--accent);
      line-height: 1;
    }
    /* Footer */
    .footer {
      background: var(--bg-footer);
      border-top: 2px solid var(--primary);
      padding: 50px 0 20px;
      color: #999;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 30px;
    }
    .social-icons {
      display: flex;
      gap: 20px;
      margin-top: 15px;
    }
    .social-icons svg {
      fill: #777;
      transition: fill 0.2s;
    }
    .social-icons svg:hover {
      fill: var(--primary);
    }
    @media (max-width: 1024px) {
      .container { padding: 0 25px; }
    }
    @media (max-width: 768px) {
      .nav-menu {
        position: fixed;
        right: -100%;
        top: 70px;
        flex-direction: column;
        background: #1A1A1A;
        width: 75%;
        height: 100vh;
        padding: 40px 30px;
        gap: 2rem;
        transition: right 0.3s ease;
      }
      .nav-menu.active {
        right: 0;
      }
      .menu-toggle { display: flex; }
      .footer-grid { grid-template-columns: repeat(2,1fr); }
    }