/* roulang page: index */
:root {
      --primary: #FF4F1E;
      --primary-dark: #E63900;
      --accent: #FFD200;
      --black: #1A1A1A;
      --gray-dark: #4A4A4A;
      --gray-light: #F5F5F5;
      --white: #FFFFFF;
      --bg: #FAFAFA;
      --shadow-card: 0 8px 30px rgba(0,0,0,0.06);
      --shadow-nav: 0 4px 12px rgba(0,0,0,0.15);
      --border-radius-card: 20px;
      --border-radius-btn: 50px;
      --transition-smooth: all 0.3s ease;
    }

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

    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--bg);
      color: var(--gray-dark);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

    a, button {
      transition: var(--transition-smooth);
    }

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

    .container {
      width: 100%;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 深色导航 */
    .header {
      position: sticky;
      top: 0;
      width: 100%;
      background: rgba(26,26,26,0.92);
      backdrop-filter: blur(12px);
      height: 72px;
      z-index: 100;
      box-shadow: var(--shadow-nav);
      display: flex;
      align-items: center;
    }

    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    .logo {
      font-size: 1.8rem;
      font-weight: 800;
      letter-spacing: 1px;
      color: var(--white);
    }
    .logo span {
      color: var(--accent);
    }

    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
      list-style: none;
    }

    .nav-links a {
      color: #ccc;
      font-weight: 500;
      position: relative;
      font-size: 1rem;
      padding: 8px 0;
    }

    .nav-links a:hover {
      color: var(--accent);
    }

    .nav-links a.active {
      color: var(--white);
      border-bottom: 3px solid var(--primary);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
    }
    .hamburger span {
      width: 28px;
      height: 3px;
      background: white;
      border-radius: 3px;
      transition: 0.3s;
    }

    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 0;
        left: 100%;
        width: 100%;
        height: 100vh;
        background: var(--black);
        flex-direction: column;
        justify-content: center;
        gap: 48px;
        font-size: 1.5rem;
        transition: 0.4s ease;
        visibility: hidden;
      }
      .nav-links.open {
        left: 0;
        visibility: visible;
      }
      .hamburger {
        display: flex;
        z-index: 110;
      }
    }

    section {
      padding: 100px 0;
    }

    /* Button System */
    .btn-primary {
      background: linear-gradient(135deg, var(--primary), var(--primary-dark));
      color: white;
      padding: 14px 36px;
      border-radius: var(--border-radius-btn);
      font-weight: 600;
      border: none;
      display: inline-block;
      cursor: pointer;
      text-align: center;
      box-shadow: 0 6px 18px rgba(255,79,30,0.3);
    }
    .btn-primary:hover {
      transform: scale(1.03);
      box-shadow: 0 8px 22px rgba(255,79,30,0.5);
    }
    .btn-secondary {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 14px 36px;
      border-radius: var(--border-radius-btn);
      font-weight: 600;
      display: inline-block;
    }
    .btn-secondary:hover {
      background: rgba(255,79,30,0.1);
    }

    /* Hero */
    #hero {
      background: linear-gradient(135deg, var(--black) 0%, #341f1a 100%);
      color: white;
      padding: 120px 0 100px;
      position: relative;
      overflow: hidden;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 48px;
    }
    .hero-image {
      flex: 1;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      min-height: 380px;
      border-radius: 30px;
    }
    .hero-content {
      flex: 1;
    }
    .hero-content h1 {
      font-size: 3.8rem;
      font-weight: 800;
      line-height: 1.2;
      margin-bottom: 1.5rem;
    }
    .hero-content p {
      font-size: 1.3rem;
      max-width: 500px;
      margin-bottom: 2.5rem;
      color: #ddd;
    }
    .btn-group {
      display: flex;
      gap: 20px;
    }

    /* 数据徽章 */
    .badge-grid {
      display: flex;
      gap: 28px;
      justify-content: center;
      flex-wrap: wrap;
    }
    .badge-card {
      background: var(--white);
      border-radius: 24px;
      padding: 30px 28px;
      text-align: center;
      box-shadow: var(--shadow-card);
      min-width: 200px;
    }
    .badge-number {
      font-size: 3rem;
      font-weight: 800;
      color: var(--accent);
      line-height: 1.1;
    }
    .badge-label {
      margin-top: 8px;
      font-weight: 500;
      color: var(--gray-dark);
    }

    /* Cards */
    .card {
      background: var(--white);
      border-radius: var(--border-radius-card);
      padding: 32px;
      box-shadow: var(--shadow-card);
      transition: all 0.3s ease;
      border-top: 4px solid var(--primary);
    }
    .card:hover {
      transform: translateY(-6px);
      box-shadow: 0 14px 34px rgba(255,79,30,0.1);
    }
    .testimonial-card {
      background: #f9f9f9;
      border-left: 4px solid var(--primary);
    }

    .section-title {
      font-size: 2.6rem;
      font-weight: 800;
      color: var(--black);
      margin-bottom: 20px;
      text-align: center;
    }
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(auto-fit , minmax(280px , 1fr));
      gap: 30px;
    }

    .faq-item {
      border-bottom: 1px solid #e0e0e0;
      padding: 20px 0;
    }
    .faq-question {
      font-size: 1.2rem;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: 0.3s;
      color: #555;
    }
    .faq-answer.open {
      max-height: 200px;
      margin-top: 12px;
    }

    footer {
      background: var(--black);
      color: #aaa;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 30px;
    }
    @media (max-width:768px) {
      .hero-grid {flex-direction: column;}
      .hero-content h1 {font-size: 2.5rem;}
      section {padding: 60px 0;}
      .footer-grid {grid-template-columns: 1fr;}
    }