/* roulang page: index */
:root {
      --primary: #E94E1B;
      --primary-hover: #C43D14;
      --secondary-dark: #1E1E1E;
      --secondary-silver: #F0F2F5;
      --accent-green: #00C48C;
      --white: #FFFFFF;
      --gray-light: #F8F9FA;
      --gray-mid: #6B7280;
      --gray-border: #E5E7EB;
      --text-main: #1E1E1E;
      --text-secondary: #4B5563;
      --shadow-sm: 0 2px 8px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
      --shadow-lg: 0 12px 32px rgba(0,0,0,0.12);
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 16px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --font-number: "Inter", "SF Pro Text", system-ui, sans-serif;
      --transition: 0.2s ease;
      --max-width: 1200px;
      --header-height: 64px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--secondary-silver);
      color: var(--text-main);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 20px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 16px;
      }
    }
    h1, h2, h3 {
      font-weight: 600;
    }
    h1 {
      font-size: 36px;
      line-height: 48px;
      letter-spacing: -0.5px;
      font-weight: 700;
    }
    h2 {
      font-size: 28px;
      line-height: 38px;
      margin-bottom: 16px;
    }
    h3 {
      font-size: 20px;
      line-height: 28px;
      margin-bottom: 8px;
    }
    p {
      font-size: 16px;
      line-height: 26px;
      color: var(--text-secondary);
      margin-bottom: 1.5em;
    }
    .text-small {
      font-size: 14px;
      line-height: 20px;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    button, .btn {
      cursor: pointer;
      font-family: var(--font-sans);
      font-weight: 600;
      border: none;
      background: none;
      transition: var(--transition);
    }
    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--header-height);
      background: var(--white);
      box-shadow: 0 1px 4px rgba(0,0,0,0.04);
      z-index: 100;
      display: flex;
      align-items: center;
    }
    .header .container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 700;
      font-size: 20px;
      color: var(--secondary-dark);
    }
    .logo-icon {
      width: 28px;
      height: 28px;
      background: var(--primary);
      border-radius: 6px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 16px;
      position: relative;
    }
    .logo-icon i {
      font-size: 18px;
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-link {
      font-size: 15px;
      font-weight: 500;
      color: var(--secondary-dark);
      transition: color var(--transition);
      white-space: nowrap;
    }
    .nav-link:hover {
      color: var(--primary);
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 10px 22px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 15px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
      border: none;
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      transform: translateY(-1px);
      box-shadow: var(--shadow-md);
    }
    .btn-outline {
      background: transparent;
      border: 1px solid var(--primary);
      color: var(--primary);
      padding: 10px 22px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 15px;
      display: inline-flex;
      align-items: center;
    }
    .btn-outline:hover {
      background: rgba(233, 78, 27, 0.08);
    }
    .hamburger {
      display: none;
      font-size: 24px;
      background: none;
      border: none;
      color: var(--secondary-dark);
    }
    @media (max-width: 1024px) {
      .nav-menu {
        gap: 20px;
      }
    }
    @media (max-width: 768px) {
      .nav-menu {
        display: none;
        position: fixed;
        top: var(--header-height);
        left: 0;
        width: 100%;
        height: calc(100vh - var(--header-height));
        background: var(--secondary-silver);
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 32px;
        z-index: 99;
      }
      .nav-menu.active {
        display: flex;
      }
      .nav-link {
        font-size: 20px;
      }
      .hamburger {
        display: block;
      }
      .header .btn-primary {
        display: none;
      }
      .nav-menu .btn-primary {
        display: inline-flex;
        margin-top: 16px;
      }
    }
    /* Hero */
    .hero {
      padding: 120px 0 80px;
      background: var(--white);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-left h1 {
      margin-bottom: 20px;
    }
    .hero-subtitle {
      font-size: 18px;
      color: var(--gray-mid);
      margin-bottom: 32px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image {
      background: linear-gradient(135deg, rgba(233,78,27,0.15), rgba(30,30,30,0.1));
      border-radius: var(--radius-lg);
      overflow: hidden;
      position: relative;
      aspect-ratio: 4/3;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .hero-image img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      border-radius: var(--radius-lg);
    }
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 32px;
      }
      .hero-image {
        order: -1;
        aspect-ratio: 16/9;
      }
      h1 {
        font-size: 28px;
        line-height: 38px;
      }
    }
    /* 通用板块 */
    section {
      padding: 80px 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }
    .section-title h2 {
      margin-bottom: 8px;
    }
    /* 亮点网格 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }
    .feature-card {
      background: var(--white);
      padding: 32px 24px;
      border-radius: var(--radius-md);
      border: 1px solid var(--gray-border);
      text-align: center;
      transition: box-shadow var(--transition), border-color var(--transition);
    }
    .feature-card:hover {
      box-shadow: var(--shadow-md);
      border-color: var(--primary);
    }
    .feature-icon {
      font-size: 32px;
      color: var(--primary);
      margin-bottom: 16px;
    }
    @media (max-width: 768px) {
      .features-grid {
        grid-template-columns: 1fr;
      }
    }
    /* 案例瀑布 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }
    .case-card {
      background: var(--white);
      border-radius: var(--radius-md);
      overflow: hidden;
      border: 1px solid var(--gray-border);
      transition: transform 0.3s, box-shadow 0.3s;
    }
    .case-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-lg);
    }
    .case-card img {
      width: 100%;
      height: 180px;
      object-fit: cover;
    }
    .case-content {
      padding: 20px;
    }
    .case-tag {
      background: var(--secondary-silver);
      color: var(--text-secondary);
      font-size: 13px;
      padding: 2px 10px;
      border-radius: 20px;
      display: inline-block;
      margin-bottom: 8px;
    }
    .case-card.wide {
      grid-column: span 2;
    }
    @media (max-width: 1024px) {
      .cases-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .case-card.wide {
        grid-column: span 2;
      }
    }
    @media (max-width: 600px) {
      .cases-grid {
        grid-template-columns: 1fr;
      }
      .case-card.wide {
        grid-column: span 1;
      }
    }
    /* 对比表 */
    .compare-table {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
      background: var(--white);
      border-radius: var(--radius-lg);
      overflow: hidden;
      border: 1px solid var(--gray-border);
    }
    .compare-col {
      padding: 32px;
    }
    .compare-col.highlight {
      background: rgba(0, 196, 140, 0.04);
    }
    .compare-item {
      display: flex;
      align-items: center;
      gap: 12px;
      padding: 12px 0;
      border-bottom: 1px solid var(--gray-border);
    }
    .compare-item i {
      font-size: 18px;
    }
    .text-green {
      color: var(--accent-green);
    }
    .text-gray {
      color: #9CA3AF;
    }
    @media (max-width: 768px) {
      .compare-table {
        grid-template-columns: 1fr;
      }
    }
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--gray-border);
    }
    .faq-question {
      width: 100%;
      background: var(--white);
      padding: 16px 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      font-size: 16px;
      text-align: left;
      border: none;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      background: var(--secondary-silver);
      padding: 0 16px;
      border-radius: 0 0 8px 8px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding: 16px;
    }
    /* CTA */
    .cta-band {
      background: var(--secondary-dark);
      text-align: center;
      padding: 80px 20px;
    }
    .cta-band h2 {
      color: white;
    }
    .cta-band p {
      color: #AAA;
      margin-bottom: 32px;
    }
    /* 页脚 */
    .footer {
      background: #111;
      color: #AAA;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      margin-bottom: 40px;
    }
    .footer-logo {
      font-size: 20px;
      font-weight: 700;
      color: white;
      margin-bottom: 12px;
    }
    .footer a {
      color: #AAA;
      font-size: 14px;
      display: block;
      margin-bottom: 8px;
    }
    .footer a:hover {
      color: var(--primary);
    }
    .copyright {
      text-align: center;
      font-size: 13px;
      border-top: 1px solid #222;
      padding-top: 24px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }