/* roulang page: index */
/* 全局设计变量与重置 */
    :root {
      --primary: #0A6EFF;
      --primary-dark: #0857D6;
      --primary-light: #E6F0FF;
      --accent: #FF5C00;
      --accent-dark: #E04E00;
      --bg: #F8FAFC;
      --bg-alt: #F1F5F9;
      --surface: #FFFFFF;
      --dark-bg: #0F172A;
      --text-main: #1E293B;
      --text-secondary: #64748B;
      --border: #E2E8F0;
      --radius-md: 12px;
      --radius-lg: 16px;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.04), 0 1px 3px rgba(0,0,0,0.02);
      --shadow-hover: 0 12px 32px rgba(10,110,255,0.12), 0 6px 12px rgba(0,0,0,0.08);
      --font-heading: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-body: "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
      --transition: 0.3s ease;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font-body);
      background-color: var(--bg);
      color: var(--text-main);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }

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

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

    button, input, select, textarea {
      font-family: inherit;
    }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 32px;
    }

    @media (max-width: 768px) {
      .container {
        padding: 0 20px;
      }
    }

    /* 排版 */
    h1 {
      font-family: var(--font-heading);
      font-size: 56px;
      font-weight: 800;
      line-height: 1.1;
      letter-spacing: -0.02em;
      color: var(--text-main);
    }
    h2 {
      font-family: var(--font-heading);
      font-size: 40px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--text-main);
    }
    h3 {
      font-family: var(--font-heading);
      font-size: 24px;
      font-weight: 600;
      line-height: 1.3;
    }
    p, .text-body {
      font-size: 16px;
      font-weight: 400;
      line-height: 1.7;
      color: var(--text-secondary);
    }
    .text-small {
      font-size: 14px;
      font-weight: 500;
    }

    @media (max-width: 640px) {
      h1 { font-size: 36px; }
      h2 { font-size: 30px; }
      h3 { font-size: 20px; }
    }

    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 32px;
      border-radius: var(--radius-md);
      font-weight: 600;
      font-size: 16px;
      transition: background var(--transition), box-shadow var(--transition), border var(--transition), transform var(--transition);
      cursor: pointer;
      border: none;
      gap: 8px;
      white-space: nowrap;
    }
    .btn-primary {
      background-color: var(--primary);
      color: white;
      box-shadow: 0 4px 12px rgba(10,110,255,0.25);
    }
    .btn-primary:hover {
      background-color: var(--primary-dark);
      box-shadow: 0 0 0 4px rgba(10,110,255,0.2), 0 8px 20px rgba(10,110,255,0.3);
      transform: translateY(-1px);
    }
    .btn-accent {
      background-color: var(--accent);
      color: white;
    }
    .btn-accent:hover {
      background-color: var(--accent-dark);
      box-shadow: 0 0 0 4px rgba(255,92,0,0.2);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
    }
    .btn-outline:hover {
      background-color: var(--primary-light);
      border-color: var(--primary-dark);
      color: var(--primary-dark);
    }

    /* 导航栏 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      z-index: 50;
      transition: background var(--transition), box-shadow var(--transition);
      background: transparent;
      backdrop-filter: blur(0px);
    }
    .site-header.scrolled {
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(12px);
      box-shadow: 0 4px 20px rgba(0,0,0,0.04);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 32px;
    }
    .logo {
      font-family: var(--font-heading);
      font-weight: 700;
      font-size: 24px;
      color: white;
      display: flex;
      align-items: center;
      gap: 8px;
      transition: color var(--transition);
    }
    .scrolled .logo {
      color: var(--text-main);
    }
    .logo-dot {
      width: 10px;
      height: 10px;
      background-color: var(--accent);
      border-radius: 50%;
      display: inline-block;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .nav-links a {
      font-weight: 500;
      color: rgba(255,255,255,0.9);
      transition: color var(--transition);
      font-size: 15px;
    }
    .scrolled .nav-links a {
      color: var(--text-main);
    }
    .nav-links a:hover {
      color: var(--accent);
    }
    .menu-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 28px;
      color: white;
      cursor: pointer;
    }
    .scrolled .menu-toggle {
      color: var(--text-main);
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
      }
      .menu-toggle {
        display: block;
      }
      .header-inner {
        padding: 0 20px;
      }
    }
    .mobile-menu {
      position: fixed;
      top: 0;
      right: 0;
      width: 75%;
      max-width: 320px;
      height: 100vh;
      background: white;
      box-shadow: -8px 0 30px rgba(0,0,0,0.1);
      transform: translateX(100%);
      transition: transform 0.4s ease;
      z-index: 100;
      padding: 24px;
      display: flex;
      flex-direction: column;
      gap: 24px;
    }
    .mobile-menu.active {
      transform: translateX(0);
    }
    .mobile-menu a {
      font-size: 18px;
      font-weight: 600;
      color: var(--text-main);
      display: block;
    }
    .menu-overlay {
      position: fixed;
      inset: 0;
      background: rgba(0,0,0,0.3);
      z-index: 99;
      display: none;
    }
    .menu-overlay.active {
      display: block;
    }

    /* 区块间距 */
    section {
      padding: 100px 0;
    }
    @media (max-width: 640px) {
      section {
        padding: 70px 0;
      }
    }

    /* Hero */
    #hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: linear-gradient(135deg, #0A1F3F 0%, #0A2A5E 100%);
      color: white;
      position: relative;
      overflow: hidden;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
      width: 100%;
    }
    .hero-left {
      flex: 1 1 55%;
      z-index: 2;
    }
    .hero-right {
      flex: 1 1 45%;
      z-index: 2;
      display: flex;
      justify-content: center;
    }
    .hero-image {
      width: 100%;
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: 0 30px 60px rgba(0,0,0,0.4);
    }
    .dynamic-text {
      color: var(--accent);
      font-weight: 700;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
      margin-top: 32px;
    }
    @media (max-width: 1024px) {
      .hero-grid {
        flex-direction: column;
        text-align: center;
        gap: 40px;
      }
      .hero-right {
        order: -1;
      }
      .hero-buttons {
        justify-content: center;
      }
    }

    /* 卡片网格 */
    .highlights-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .highlight-card {
      background: var(--surface);
      padding: 32px;
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .highlight-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .icon-circle {
      width: 48px;
      height: 48px;
      color: var(--primary);
      margin-bottom: 20px;
    }
    .big-card {
      grid-column: span 2;
      display: flex;
      gap: 24px;
      background: var(--surface);
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: var(--shadow-card);
    }
    .data-card {
      background: var(--surface);
      padding: 32px;
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-card);
      display: flex;
      flex-direction: column;
      justify-content: center;
    }
    .big-number {
      font-size: 48px;
      font-weight: 800;
      color: var(--accent);
    }
    @media (max-width: 768px) {
      .highlights-grid {
        grid-template-columns: 1fr;
      }
      .big-card {
        grid-column: span 1;
        flex-direction: column;
      }
    }

    /* 案例瀑布 */
    .masonry {
      columns: 3;
      column-gap: 24px;
    }
    .masonry-item {
      break-inside: avoid;
      margin-bottom: 24px;
      background: white;
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .masonry-item:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .masonry-item img {
      width: 100%;
      object-fit: cover;
    }
    @media (max-width: 768px) {
      .masonry {
        columns: 2;
      }
    }
    @media (max-width: 520px) {
      .masonry {
        columns: 1;
      }
    }

    /* 对比 */
    .compare-row {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .vs-badge {
      background: white;
      border-radius: 50%;
      width: 60px;
      height: 60px;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 800;
      color: var(--accent);
      box-shadow: var(--shadow-card);
    }
    @media (max-width: 768px) {
      .compare-row {
        flex-direction: column;
      }
    }

    /* FAQ 双栏 */
    .faq-grid {
      display: flex;
      gap: 40px;
    }
    .faq-left {
      flex: 1 1 40%;
    }
    .faq-right {
      flex: 1 1 60%;
      background: var(--bg-alt);
      border-radius: var(--radius-lg);
      padding: 32px;
    }
    @media (max-width: 768px) {
      .faq-grid {
        flex-direction: column;
      }
    }

    /* 联系 */
    .contact-dark {
      background: var(--dark-bg);
      color: white;
    }
    .form-row {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .form-input {
      flex: 1;
      padding: 14px 16px;
      border-radius: var(--radius-md);
      border: none;
      background: rgba(255,255,255,0.1);
      color: white;
    }

    /* 页脚 */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }
    @media (max-width: 520px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }