/* roulang page: index */
:root {
      --primary: #1A1A2E;
      --accent: #E43F3F;
      --bg: #FAFAFA;
      --bg-alt: #F0F0F5;
      --text-title: #1A1A2E;
      --text-body: #4A4A5A;
      --text-muted: #8A8A9A;
      --gold: #FFB800;
      --white: #FFFFFF;
      --border-light: #E8E8EC;
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 20px;
      --shadow-sm: 0 2px 8px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 30px rgba(0,0,0,0.08);
      --transition: 0.2s ease;
      --container-max: 1200px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--bg);
      color: var(--text-body);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    img {
      max-width: 100%;
      display: block;
      height: auto;
    }
    button, input {
      font-family: inherit;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: var(--white);
      border-bottom: 1px solid var(--border-light);
      z-index: 100;
      transition: box-shadow 0.3s ease;
      display: flex;
      align-items: center;
    }
    .site-header.scrolled {
      box-shadow: 0 2px 20px rgba(0,0,0,0.06);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 700;
      font-size: 22px;
      color: var(--primary);
      letter-spacing: -0.3px;
    }
    .logo-icon {
      width: 32px;
      height: 32px;
      background: var(--accent);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-weight: 700;
      font-size: 18px;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      list-style: none;
      font-weight: 500;
      font-size: 15px;
      color: var(--text-body);
    }
    .nav-links a {
      padding: 8px 0;
      border-bottom: 2px solid transparent;
      transition: var(--transition);
    }
    .nav-links a:hover {
      color: var(--accent);
      border-bottom-color: var(--accent);
    }
    .header-actions {
      display: flex;
      align-items: center;
      gap: 16px;
    }
    .search-box {
      background: #F5F5F7;
      border-radius: var(--radius-input);
      padding: 8px 16px;
      display: flex;
      align-items: center;
      gap: 6px;
      color: var(--text-muted);
      font-size: 14px;
    }
    .search-box input {
      border: none;
      background: transparent;
      outline: none;
      width: 120px;
      font-size: 14px;
    }
    .btn-primary {
      background: var(--accent);
      color: white;
      border: none;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
      cursor: pointer;
      box-shadow: 0 4px 10px rgba(228,63,63,0.25);
      transition: all 0.2s ease;
      letter-spacing: 0.5px;
    }
    .btn-primary:hover {
      background: #c93030;
      transform: translateY(-2px);
      box-shadow: 0 8px 18px rgba(228,63,63,0.35);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 15px;
      cursor: pointer;
      transition: all 0.2s ease;
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
      transform: translateY(-2px);
    }
    .btn-text {
      color: var(--accent);
      font-weight: 600;
      font-size: 15px;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      transition: var(--transition);
    }
    .btn-text:hover {
      text-decoration: underline;
      color: #b32d2d;
    }
    /* 汉堡菜单（移动端） */
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--primary);
      border-radius: 2px;
    }
    @media (max-width: 768px) {
      .nav-links, .header-actions .search-box {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .mobile-menu {
        display: none;
        position: absolute;
        top: 72px;
        left: 0;
        width: 100%;
        background: white;
        flex-direction: column;
        padding: 20px;
        box-shadow: 0 10px 20px rgba(0,0,0,0.05);
        gap: 20px;
      }
      .mobile-menu.active {
        display: flex;
      }
    }
    /* Hero */
    .hero {
      padding: 140px 0 100px;
      background: var(--white);
      display: flex;
      align-items: center;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-content {
      flex: 1 1 50%;
    }
    .hero h1 {
      font-size: 48px;
      line-height: 1.2;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: -0.5px;
      margin-bottom: 20px;
    }
    .hero-sub {
      font-size: 18px;
      color: var(--text-body);
      margin-bottom: 32px;
      line-height: 1.6;
    }
    .hero-actions {
      display: flex;
      gap: 20px;
      align-items: center;
    }
    .hero-image {
      flex: 1 1 45%;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: 24px;
      min-height: 360px;
      box-shadow: 0 20px 35px rgba(0,0,0,0.08);
    }
    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
      }
      .hero h1 {
        font-size: 36px;
      }
      .hero-image {
        width: 100%;
        min-height: 260px;
      }
    }
    /* 通用板块 */
    .section {
      padding: 100px 0;
    }
    .section-alt {
      background: var(--bg-alt);
    }
    .section-title {
      font-size: 36px;
      font-weight: 600;
      color: var(--primary);
      margin-bottom: 16px;
      text-align: center;
    }
    .section-desc {
      color: var(--text-muted);
      text-align: center;
      max-width: 680px;
      margin: 0 auto 48px;
    }
    /* 卡片网格 */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    @media (max-width: 1024px) {
      .grid-3 {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 640px) {
      .grid-3 {
        grid-template-columns: 1fr;
      }
    }
    .card {
      background: white;
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-sm);
      transition: all 0.25s ease;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .feature-icon {
      font-size: 32px;
      color: var(--accent);
      margin-bottom: 20px;
    }
    .card h3 {
      font-size: 22px;
      font-weight: 600;
      color: var(--primary);
      margin-bottom: 12px;
    }
    /* 方案交替布局 */
    .solution-row {
      display: flex;
      align-items: center;
      gap: 48px;
      margin-bottom: 80px;
    }
    .solution-row.reverse {
      flex-direction: row-reverse;
    }
    .solution-text {
      flex: 1;
    }
    .solution-number {
      font-size: 64px;
      font-weight: 700;
      color: rgba(26,26,46,0.06);
      margin-bottom: 8px;
    }
    .solution-list {
      list-style: none;
      margin-top: 16px;
    }
    .solution-list li {
      padding-left: 20px;
      position: relative;
      margin-bottom: 8px;
      color: var(--text-body);
    }
    .solution-list li::before {
      content: "—";
      color: var(--accent);
      position: absolute;
      left: 0;
      font-weight: 600;
    }
    .solution-image {
      flex: 1;
      background: #e9e9f0;
      border-radius: 16px;
      min-height: 280px;
      background-size: cover;
      background-position: center;
    }
    @media (max-width: 768px) {
      .solution-row, .solution-row.reverse {
        flex-direction: column;
      }
    }
    /* 场景卡片 */
    .scenario-card {
      background: #f7f7fc;
      border-left: 4px solid var(--accent);
      padding: 28px;
      border-radius: 0 var(--radius-card) var(--radius-card) 0;
    }
    /* 案例数字 */
    .case-number {
      font-size: 48px;
      font-weight: 700;
      color: var(--gold);
      line-height: 1;
      margin-bottom: 8px;
    }
    /* FAQ */
    .faq-item {
      background: white;
      border-radius: var(--radius-card);
      margin-bottom: 16px;
      overflow: hidden;
      border: 1px solid var(--border-light);
    }
    .faq-question {
      padding: 20px 24px;
      background: #FAFAFA;
      font-weight: 600;
      font-size: 18px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      transition: background 0.2s;
    }
    .faq-question:hover {
      background: #f0f0f5;
    }
    .faq-answer {
      padding: 0 24px 20px;
      color: var(--text-body);
      display: none;
    }
    .faq-item.active .faq-answer {
      display: block;
    }
    .faq-item.active .faq-icon {
      transform: rotate(180deg);
    }
    /* CTA 横幅 */
    .cta-banner {
      background: linear-gradient(135deg, #1A1A2E 0%, #E43F3F 100%);
      padding: 80px 0;
      text-align: center;
      color: white;
    }
    .cta-banner h2 {
      font-size: 36px;
      font-weight: 700;
    }
    .footer {
      background: #1A1A2E;
      color: #B0B0C0;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
      .section {
        padding: 60px 0;
      }
      .section-title {
        font-size: 28px;
      }
    }