/* roulang page: index */
:root {
      --primary: #4A3AFF;
      --primary-hover: #3B2ECC;
      --accent: #FF6B2B;
      --accent-hover: #E55A1F;
      --dark: #1E1E2A;
      --gray-bg: #F4F5FA;
      --white: #FFFFFF;
      --text-main: #1E1E2A;
      --text-muted: #6B6B7B;
      --border-light: #E0E0E0;
      --card-radius: 12px;
      --card-shadow: 0 4px 20px rgba(0,0,0,0.04);
      --card-shadow-hover: 0 8px 30px rgba(0,0,0,0.08);
    }

    * {
      box-sizing: border-box;
    }

    body {
      font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      margin: 0;
      background-color: var(--gray-bg);
      color: var(--text-main);
      line-height: 1.8;
      font-weight: 400;
      font-size: 16px;
      display: flex;
      min-height: 100vh;
    }

    /* 左侧 App Shell 导航 */
    .app-nav {
      position: fixed;
      left: 0;
      top: 0;
      height: 100vh;
      width: 72px;
      background-color: var(--dark);
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 24px 0;
      z-index: 100;
      transition: width 0.25s ease;
      overflow: hidden;
      box-shadow: 2px 0 15px rgba(0,0,0,0.08);
    }

    .app-nav:hover {
      width: 240px;
    }

    .nav-logo {
      width: 100%;
      padding: 0 20px;
      margin-bottom: 40px;
      display: flex;
      align-items: center;
      justify-content: center;
      white-space: nowrap;
    }

    .nav-logo .logo-icon {
      font-size: 28px;
      font-weight: 700;
      color: white;
      letter-spacing: 2px;
      background: var(--primary);
      width: 42px;
      height: 42px;
      display: flex;
      align-items: center;
      justify-content: center;
      border-radius: 10px;
      flex-shrink: 0;
    }

    .nav-logo .logo-text {
      color: white;
      font-weight: 700;
      font-size: 20px;
      margin-left: 16px;
      opacity: 0;
      transition: opacity 0.2s;
    }

    .app-nav:hover .logo-text {
      opacity: 1;
    }

    .nav-links {
      list-style: none;
      margin: 0;
      padding: 0;
      width: 100%;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 8px;
    }

    .nav-links li {
      width: 100%;
    }

    .nav-links a {
      display: flex;
      align-items: center;
      padding: 14px 24px;
      color: #B0B0C0;
      text-decoration: none;
      font-size: 15px;
      font-weight: 500;
      transition: all 0.2s;
      white-space: nowrap;
      border-left: 3px solid transparent;
    }

    .nav-links a i {
      font-size: 20px;
      width: 24px;
      text-align: center;
      margin-right: 18px;
    }

    .nav-links a span {
      opacity: 0;
      transition: opacity 0.2s;
    }

    .app-nav:hover .nav-links a span {
      opacity: 1;
    }

    .nav-links a:hover,
    .nav-links a.active {
      color: white;
      background-color: rgba(255,255,255,0.08);
      border-left-color: var(--accent);
    }

    /* 移动端顶部导航 */
    .mobile-header {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 56px;
      background: var(--dark);
      z-index: 99;
      align-items: center;
      justify-content: space-between;
      padding: 0 20px;
      box-shadow: 0 2px 10px rgba(0,0,0,0.2);
    }

    .mobile-logo {
      color: white;
      font-weight: 700;
      font-size: 22px;
      letter-spacing: 1px;
    }

    .hamburger {
      color: white;
      font-size: 24px;
      background: none;
      border: none;
      cursor: pointer;
    }

    .mobile-drawer {
      position: fixed;
      top: 56px;
      left: 0;
      width: 100%;
      background: var(--dark);
      padding: 0 0 24px;
      display: none;
      flex-direction: column;
      z-index: 98;
    }

    .mobile-drawer a {
      color: #B0B0C0;
      padding: 14px 24px;
      border-bottom: 1px solid rgba(255,255,255,0.05);
      font-size: 16px;
      text-decoration: none;
    }

    .mobile-drawer a i {
      margin-right: 12px;
    }

    /* 主内容区域 */
    .main-content {
      margin-left: 72px;
      flex: 1;
      width: calc(100% - 72px);
      background: var(--gray-bg);
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    section {
      padding: 100px 0;
    }

    @media (max-width: 1024px) {
      section {
        padding: 70px 0;
      }
    }

    @media (max-width: 768px) {
      .app-nav {
        display: none;
      }
      .mobile-header {
        display: flex;
      }
      .main-content {
        margin-left: 0;
        width: 100%;
        padding-top: 56px;
      }
      section {
        padding: 60px 0;
      }
    }

    /* 通用标题 */
    h1 {
      font-size: 48px;
      font-weight: 700;
      letter-spacing: -1px;
      line-height: 1.2;
    }
    h2 {
      font-size: 36px;
      font-weight: 700;
      margin-bottom: 16px;
    }
    h3 {
      font-size: 24px;
      font-weight: 600;
    }
    p {
      max-width: 720px;
      color: var(--text-muted);
    }

    @media (max-width: 768px) {
      h1 { font-size: 32px; }
      h2 { font-size: 28px; }
      h3 { font-size: 20px; }
    }

    /* 按钮 */
    .btn {
      display: inline-block;
      padding: 14px 32px;
      border-radius: 8px;
      font-weight: 600;
      text-decoration: none;
      transition: all 0.2s ease;
      cursor: pointer;
      border: 2px solid transparent;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      border-color: var(--primary);
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      border-color: var(--primary-hover);
    }
    .btn-outline {
      background: transparent;
      color: var(--primary);
      border-color: var(--primary);
    }
    .btn-outline:hover {
      background: rgba(74,58,255,0.05);
    }
    .btn-accent {
      background: var(--accent);
      color: white;
      border-color: var(--accent);
    }
    .btn-accent:hover {
      background: var(--accent-hover);
      border-color: var(--accent-hover);
    }

    /* Hero */
    #hero {
      background: white;
      min-height: 90vh;
      display: flex;
      align-items: center;
      position: relative;
      background-image: radial-gradient(circle at 20% 30%, rgba(0,0,0,0.02) 1px, transparent 1px);
      background-size: 40px 40px;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 48px;
    }
    .hero-left {
      flex: 1;
    }
    .hero-right {
      flex: 1;
      position: relative;
    }
    .hero-right img {
      width: 100%;
      border-radius: 16px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.1);
    }
    .data-badge {
      position: absolute;
      bottom: -20px;
      left: -20px;
      background: white;
      padding: 16px 24px;
      border-radius: 16px;
      box-shadow: 0 12px 28px rgba(0,0,0,0.08);
      font-weight: 700;
      color: var(--primary);
    }

    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column-reverse;
      }
      .hero-right {
        margin-bottom: 32px;
      }
      .data-badge {
        bottom: -10px;
        left: 10px;
      }
    }

    /* 卡片 */
    .card {
      background: white;
      border-radius: var(--card-radius);
      box-shadow: var(--card-shadow);
      padding: 32px;
      transition: all 0.3s ease;
      height: 100%;
    }
    .card:hover {
      box-shadow: var(--card-shadow-hover);
      transform: translateY(-4px);
    }

    .icon-circle {
      width: 64px;
      height: 64px;
      background: rgba(74,58,255,0.08);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary);
      font-size: 28px;
      transition: 0.2s;
    }
    .card:hover .icon-circle {
      background: var(--primary);
      color: white;
    }

    /* 产品图文交替 */
    .service-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }
    .service-row.reverse {
      flex-direction: row-reverse;
    }
    .service-img img {
      width: 100%;
      border-radius: 16px;
    }
    @media (max-width: 768px) {
      .service-row, .service-row.reverse {
        flex-direction: column;
      }
    }

    /* 案例卡片 */
    .case-card img {
      width: 100%;
      aspect-ratio: 16/10;
      object-fit: cover;
      border-radius: 12px 12px 0 0;
    }
    .case-card .card-body {
      padding: 20px;
    }
    .tag {
      background: #F4F5FA;
      color: var(--primary);
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 13px;
    }

    /* FAQ */
    .accordion-title {
      font-size: 18px;
      font-weight: 600;
      background: white;
      border: none;
      border-radius: 8px;
      padding: 18px 24px;
    }
    .accordion-content {
      background: #FAFAFC;
      padding: 20px;
    }

    /* 表单 */
    .form-input {
      border: none;
      border-bottom: 2px solid #E0E0E0;
      border-radius: 0;
      padding: 12px 0;
      transition: 0.3s;
      background: transparent;
    }
    .form-input:focus {
      border-bottom-color: var(--primary);
      box-shadow: none;
    }

    footer {
      background: var(--dark);
      color: #B0B0C0;
      padding: 60px 0 30px;
    }
    footer a {
      color: white;
    }