/* roulang page: index */
:root {
      --primary: #E8452D;
      --primary-dark: #C13A25;
      --secondary-dark: #1E1E24;
      --secondary-light: #FAFAFA;
      --accent: #FFB800;
      --text-body: #333333;
      --text-muted: #666666;
      --border-light: #E0E0E0;
      --success-green: #0F9D58;
      --white: #FFFFFF;
      --card-shadow: 0 4px 12px rgba(0,0,0,0.06);
      --card-hover-shadow: 0 8px 24px rgba(232,69,45,0.15);
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-pill: 50px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
      --transition: all 0.25s ease;
      --container-max: 1200px;
      --section-padding: 80px 20px;
      --mobile-section-padding: 50px 16px;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--secondary-light);
      color: var(--text-body);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      outline: none;
      transition: var(--transition);
    }

    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 20px;
    }

    @media (max-width: 768px) {
      .container {
        padding: 0 16px;
      }
    }

    /* 导航栏 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: rgba(30,30,36,0.88);
      backdrop-filter: blur(10px);
      -webkit-backdrop-filter: blur(10px);
      transition: background 0.3s;
      border-bottom: 1px solid rgba(255,255,255,0.08);
    }

    .navbar.scrolled {
      background: #1E1E24;
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 20px;
      height: 70px;
    }

    .logo {
      font-size: 24px;
      font-weight: 800;
      color: var(--white);
      letter-spacing: 1px;
      white-space: nowrap;
    }
    .logo span {
      color: var(--accent);
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 30px;
      list-style: none;
    }

    .nav-link {
      color: #CCCCCC;
      font-weight: 500;
      font-size: 16px;
      position: relative;
      padding: 4px 0;
    }

    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 50%;
      transform: translateX(-50%) scaleX(0);
      width: 100%;
      height: 2px;
      background: var(--accent);
      transition: transform 0.25s;
      transform-origin: center;
    }

    .nav-link:hover {
      color: var(--accent);
    }
    .nav-link:hover::after {
      transform: translateX(-50%) scaleX(1);
    }

    .btn-nav {
      background: var(--primary);
      color: white;
      padding: 10px 24px;
      border-radius: var(--radius-pill);
      font-weight: 600;
      font-size: 15px;
      white-space: nowrap;
      box-shadow: 0 4px 10px rgba(232,69,45,0.3);
    }
    .btn-nav:hover {
      background: var(--primary-dark);
      box-shadow: 0 6px 14px rgba(232,69,45,0.5);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: transparent;
      border: none;
      cursor: pointer;
      padding: 8px;
    }
    .hamburger span {
      width: 26px;
      height: 3px;
      background: white;
      border-radius: 3px;
      transition: 0.3s;
    }

    @media (max-width: 992px) {
      .nav-menu {
        position: fixed;
        top: 70px;
        left: 0;
        width: 100%;
        background: #1E1E24;
        flex-direction: column;
        gap: 28px;
        padding: 40px 30px;
        transform: translateY(-120%);
        opacity: 0;
        transition: 0.35s ease;
        border-radius: 0 0 16px 16px;
      }
      .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
      }
      .hamburger {
        display: flex;
      }
      .btn-nav {
        margin-top: 10px;
      }
    }

    /* 通用板块 */
    section {
      padding: var(--section-padding);
    }
    @media (max-width: 768px) {
      section {
        padding: var(--mobile-section-padding);
      }
    }

    .section-title {
      font-size: 36px;
      font-weight: 700;
      color: var(--secondary-dark);
      margin-bottom: 16px;
      text-align: center;
    }
    .section-title::after {
      content: '';
      display: block;
      width: 70px;
      height: 4px;
      background: var(--primary);
      margin: 16px auto 0;
      border-radius: 2px;
    }
    .section-sub {
      color: var(--text-muted);
      text-align: center;
      max-width: 700px;
      margin: 0 auto 48px;
    }

    /* Hero */
    .hero {
      min-height: 100vh;
      background: linear-gradient(135deg, rgba(0,0,0,0.75) 0%, rgba(30,30,36,0.5) 100%), url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      display: flex;
      align-items: center;
      justify-content: center;
      text-align: left;
      color: white;
      position: relative;
    }
    .hero-content {
      max-width: 800px;
      padding: 0 20px;
    }
    .hero h1 {
      font-size: 52px;
      font-weight: 800;
      line-height: 1.2;
      margin-bottom: 20px;
      color: white;
    }
    .hero .subtitle {
      font-size: 20px;
      margin-bottom: 36px;
      color: rgba(255,255,255,0.9);
    }
    .hero-buttons {
      display: flex;
      flex-wrap: wrap;
      gap: 16px;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 17px;
      display: inline-block;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      box-shadow: 0 0 14px rgba(232,69,45,0.5);
    }
    .btn-outline-light {
      border: 2px solid white;
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      background: transparent;
    }
    .btn-outline-light:hover {
      background: white;
      color: var(--secondary-dark);
    }
    @media (max-width: 768px) {
      .hero {
        min-height: 80vh;
        text-align: center;
      }
      .hero h1 {
        font-size: 36px;
      }
      .hero-buttons {
        justify-content: center;
      }
    }

    /* 卡片网格 */
    .grid-3, .grid-4 {
      display: grid;
      gap: 24px;
    }
    .grid-3 { grid-template-columns: repeat(3, 1fr); }
    .grid-4 { grid-template-columns: repeat(4, 1fr); }
    @media (max-width: 992px) {
      .grid-4 { grid-template-columns: repeat(2, 1fr); }
      .grid-3 { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 600px) {
      .grid-4, .grid-3 { grid-template-columns: 1fr; }
    }

    .feature-card {
      background: white;
      border-radius: var(--radius-md);
      padding: 32px 24px;
      box-shadow: var(--card-shadow);
      transition: var(--transition);
      text-align: center;
    }
    .feature-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--card-hover-shadow);
    }
    .feature-icon {
      font-size: 40px;
      margin-bottom: 16px;
      color: var(--primary);
    }

    .project-card {
      background: white;
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--card-shadow);
      transition: var(--transition);
      position: relative;
    }
    .project-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--card-hover-shadow);
    }
    .project-img {
      height: 200px;
      object-fit: cover;
      width: 100%;
    }
    .project-body {
      padding: 20px;
    }
    .badge {
      background: var(--accent);
      color: #1E1E24;
      font-weight: 700;
      font-size: 12px;
      padding: 4px 10px;
      border-radius: 20px;
      display: inline-block;
    }

    .stats-band {
      background: #1E1E24;
      color: white;
      text-align: center;
      padding: 70px 20px;
    }
    .stats-grid {
      display: flex;
      justify-content: center;
      gap: 50px;
      flex-wrap: wrap;
    }
    .stat-number {
      font-size: 44px;
      font-weight: 800;
      color: var(--accent);
    }

    .case-card {
      display: flex;
      background: white;
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--card-shadow);
      margin-bottom: 24px;
    }
    .case-img {
      width: 45%;
      object-fit: cover;
    }
    .case-text {
      padding: 30px;
    }
    @media (max-width: 768px) {
      .case-card {
        flex-direction: column;
      }
      .case-img { width: 100%; height: 220px; }
    }

    .faq-item {
      background: white;
      border-bottom: 1px solid var(--border-light);
      padding: 18px 20px;
      cursor: pointer;
    }
    .faq-question {
      font-weight: 700;
      display: flex;
      justify-content: space-between;
    }

    .cta-section {
      background: linear-gradient(135deg, #E8452D, #C13A25);
      text-align: center;
      color: white;
      padding: 80px 20px;
    }
    .btn-cta-large {
      background: var(--accent);
      color: #1E1E24;
      font-weight: 800;
      padding: 18px 48px;
      border-radius: var(--radius-pill);
      font-size: 20px;
      display: inline-block;
      margin-top: 24px;
    }
    .btn-cta-large:hover {
      transform: scale(1.05);
      box-shadow: 0 12px 24px rgba(0,0,0,0.2);
    }

    footer {
      background: #1E1E24;
      color: #BBBBBB;
      padding: 60px 20px 20px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 30px;
    }
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr; }
    }
    .footer-logo {
      font-size: 24px;
      font-weight: 800;
      color: white;
    }