/* roulang page: index */
:root {
      --primary: #E8451E;
      --primary-dark: #c0392b;
      --secondary: #1E1E1E;
      --bg-light: #F8F8F5;
      --accent: #FFB800;
      --accent-dark: #e6a800;
      --success: #2E7D32;
      --danger: #C62828;
      --white: #FFFFFF;
      --card-bg: #FFFFFF;
      --border-light: #eaeaea;
      --text-main: #1E1E1E;
      --text-body: #4A4A4A;
      --text-muted: #8A8A8A;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.06);
      --shadow-card-hover: 0 12px 32px rgba(0,0,0,0.1);
      --shadow-cta: 0 8px 24px rgba(232,69,30,0.35);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', 'Inter', system-ui, -apple-system, sans-serif;
      --max-width: 1280px;
      --nav-height: 72px;
      --transition: 0.2s ease;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-body);
      line-height: 1.75;
      font-size: 16px;
      scroll-behavior: smooth;
    }
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 板块通用间距 */
    section {
      padding: 100px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 60px 0;
      }
      .container {
        padding: 0 20px;
      }
    }
    h2.section-title {
      font-size: 36px;
      line-height: 1.3;
      font-weight: 700;
      color: var(--text-main);
      text-align: center;
      margin-bottom: 16px;
      position: relative;
    }
    h2.section-title::after {
      content: '';
      display: block;
      width: 32px;
      height: 4px;
      background: var(--primary);
      margin: 16px auto 0;
      border-radius: 2px;
    }
    @media (max-width: 768px) {
      h2.section-title {
        font-size: 28px;
      }
    }
    /* 导航栏 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(0,0,0,0.05);
      z-index: 1000;
      display: flex;
      align-items: center;
      transition: var(--transition);
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    .logo {
      display: flex;
      align-items: center;
      text-decoration: none;
      font-weight: 700;
      font-size: 22px;
      color: var(--secondary);
      letter-spacing: 1px;
    }
    .logo-icon {
      display: flex;
      align-items: center;
      margin-right: 10px;
    }
    .logo-icon i {
      font-size: 26px;
      color: var(--primary);
    }
    .nav-menu {
      display: flex;
      list-style: none;
      gap: 32px;
      align-items: center;
    }
    .nav-menu a {
      text-decoration: none;
      color: var(--text-body);
      font-weight: 500;
      font-size: 16px;
      position: relative;
      padding: 8px 0;
      transition: color var(--transition);
    }
    .nav-menu a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width var(--transition);
    }
    .nav-menu a:hover {
      color: var(--primary);
    }
    .nav-menu a:hover::after {
      width: 100%;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      cursor: pointer;
      gap: 5px;
      z-index: 1100;
    }
    .hamburger span {
      width: 28px;
      height: 3px;
      background: var(--secondary);
      border-radius: 3px;
      transition: 0.3s;
    }
    .mobile-overlay {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(30,30,30,0.95);
      backdrop-filter: blur(8px);
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      gap: 40px;
      z-index: 1050;
      opacity: 0;
      visibility: hidden;
      transition: 0.3s;
    }
    .mobile-overlay.active {
      opacity: 1;
      visibility: visible;
    }
    .mobile-overlay a {
      color: white;
      font-size: 28px;
      font-weight: 600;
      text-decoration: none;
      transition: color 0.2s;
    }
    .mobile-overlay a:hover {
      color: var(--primary);
    }
    @media (max-width: 768px) {
      .nav-menu {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .nav-container {
        padding: 0 20px;
      }
      .navbar {
        height: 60px;
      }
    }
    /* 按钮全局 */
    .btn {
      display: inline-block;
      padding: 14px 32px;
      font-weight: 600;
      border-radius: var(--radius-btn);
      text-decoration: none;
      transition: all var(--transition);
      cursor: pointer;
      border: none;
      font-size: 16px;
      text-align: center;
    }
    .btn-primary {
      background: linear-gradient(135deg, var(--primary), var(--accent));
      color: white;
      box-shadow: var(--shadow-cta);
    }
    .btn-primary:hover {
      filter: brightness(1.1);
      transform: translateY(-2px);
      box-shadow: 0 12px 28px rgba(232,69,30,0.45);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
    }
    .btn-outline:hover {
      background: rgba(232,69,30,0.08);
    }
    .btn-accent {
      background: var(--accent);
      color: var(--secondary);
      box-shadow: 0 8px 20px rgba(255,184,0,0.3);
    }
    .btn-accent:hover {
      background: var(--accent-dark);
    }
    /* Hero */
    .hero {
      padding-top: calc(var(--nav-height) + 60px);
      padding-bottom: 60px;
      display: flex;
      align-items: center;
      min-height: 100vh;
      background: var(--bg-light);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-content h1 {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--text-main);
      margin-bottom: 24px;
    }
    .hero-content .subtitle {
      font-size: 18px;
      color: var(--text-body);
      margin-bottom: 32px;
      max-width: 90%;
    }
    .hero-buttons {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }
    .hero-image {
      width: 100%;
      border-radius: 12px;
      overflow: hidden;
      box-shadow: 0 20px 40px rgba(0,0,0,0.12);
    }
    .hero-image img {
      width: 100%;
      height: auto;
      display: block;
      object-fit: cover;
      aspect-ratio: 4/3;
    }
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
      }
      .hero-content h1 {
        font-size: 32px;
      }
      .hero-image {
        order: -1;
        margin-bottom: 24px;
      }
    }
    /* 核心优势网格 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
      margin-top: 48px;
    }
    .feature-item {
      background: var(--white);
      padding: 32px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .feature-item:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    .feature-icon {
      font-size: 32px;
      color: var(--primary);
      margin-bottom: 16px;
    }
    .feature-item h3 {
      font-size: 20px;
      font-weight: 600;
      color: var(--text-main);
      margin-bottom: 12px;
    }
    @media (max-width: 768px) {
      .features-grid {
        grid-template-columns: 1fr;
      }
    }
    /* 服务卡片 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
      margin-top: 48px;
    }
    .service-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .service-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-card-hover);
    }
    .card-img {
      height: 200px;
      background-size: cover;
      background-position: center;
      position: relative;
    }
    .card-img-overlay {
      position: absolute;
      bottom: 0;
      left: 0;
      width: 100%;
      padding: 20px;
      background: linear-gradient(transparent, rgba(0,0,0,0.7));
      color: white;
      font-weight: 700;
      font-size: 20px;
    }
    .card-body {
      padding: 24px;
    }
    .card-body ul {
      list-style: none;
      margin-bottom: 20px;
    }
    .card-body li {
      margin-bottom: 10px;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .card-body li i {
      color: var(--primary);
      font-size: 14px;
    }
    .link-arrow {
      color: var(--primary);
      font-weight: 600;
      text-decoration: none;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      transition: gap 0.2s;
    }
    .link-arrow:hover {
      gap: 12px;
    }
    @media (max-width: 768px) {
      .services-grid {
        grid-template-columns: 1fr;
      }
    }
    /* 案例瀑布流 */
    .cases-masonry {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      margin-top: 48px;
    }
    .case-card {
      background: var(--white);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .case-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    .case-img {
      width: 100%;
      height: 220px;
      object-fit: cover;
    }
    .case-info {
      padding: 20px;
    }
    .case-tags {
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
      margin: 10px 0;
    }
    .tag {
      background: #f0f0f0;
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 12px;
      color: var(--text-muted);
    }
    @media (max-width: 768px) {
      .cases-masonry {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 480px) {
      .cases-masonry {
        grid-template-columns: 1fr;
      }
    }
    /* 对比表 */
    .compare-table {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 32px;
      margin-top: 48px;
    }
    .compare-col {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-card);
    }
    .compare-col h3 {
      font-size: 24px;
      margin-bottom: 24px;
    }
    .compare-row {
      display: flex;
      justify-content: space-between;
      padding: 12px 0;
      border-bottom: 1px solid #eee;
    }
    .text-success i { color: var(--success); }
    .text-danger i { color: var(--danger); }
    @media (max-width: 768px) {
      .compare-table {
        grid-template-columns: 1fr;
      }
    }
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 48px auto 0;
    }
    .faq-item {
      background: var(--white);
      border-radius: var(--radius-card);
      margin-bottom: 12px;
      box-shadow: 0 2px 8px rgba(0,0,0,0.04);
      overflow: hidden;
    }
    .faq-question {
      padding: 20px 24px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      background: var(--white);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      background: #fafafa;
      padding: 0 24px;
    }
    .faq-answer p {
      padding: 16px 0;
      color: var(--text-body);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
    }
    /* CTA 横幅 */
    .cta-band {
      background: var(--secondary);
      color: white;
      text-align: center;
      padding: 80px 0;
    }
    .cta-band h2 {
      color: white;
      font-size: 36px;
    }
    .cta-band .btn {
      margin-top: 24px;
    }
    /* 页脚 */
    .footer {
      background: var(--secondary);
      color: #B0B0B0;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer a {
      color: #B0B0B0;
      text-decoration: none;
    }
    .footer a:hover {
      color: white;
    }
    .social-icons i {
      font-size: 20px;
      margin-right: 16px;
      transition: color 0.2s;
    }
    .social-icons i:hover {
      color: var(--primary);
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }