/* roulang page: index */
/* ----- 设计变量 ----- */
    :root {
      --primary: #1A5FDC;
      --primary-hover: #1549B0;
      --accent: #FF6B3D;
      --accent-hover: #E85D32;
      --bg-light: #F8FAFC;
      --card-white: #FFFFFF;
      --text-main: #1E293B;
      --text-muted: #64748B;
      --text-light: #94A3B8;
      --border-light: #E2E8F0;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-hover: 0 12px 30px rgba(0,0,0,0.08);
      --radius-md: 12px;
      --radius-lg: 16px;
      --radius-xl: 24px;
      --transition: 0.25s ease;
      --container: 1200px;
      --header-height: 80px;
    }
    /* 全局重置与基础样式 */
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: "Inter", "PingFang SC", "Microsoft YaHei", sans-serif;
      background-color: var(--bg-light);
      color: var(--text-main);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: var(--container);
      margin: 0 auto;
      padding: 0 32px;
    }
    h1, h2, h3, h4 {
      font-weight: 700;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition);
    }
    img {
      max-width: 100%;
      display: block;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      transition: all var(--transition);
    }
    /* 导航 (沉浸式毛玻璃) */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255,255,255,0.88);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-light);
      height: var(--header-height);
      display: flex;
      align-items: center;
    }
    .header-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 800;
      font-size: 1.5rem;
      color: var(--text-main);
      letter-spacing: -0.3px;
    }
    .logo i {
      color: var(--primary);
      font-size: 2rem;
    }
    .logo span {
      background: linear-gradient(135deg, var(--primary) 0%, #3B82F6 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-link {
      font-weight: 500;
      color: var(--text-muted);
      padding: 8px 0;
      position: relative;
      font-size: 0.95rem;
    }
    .nav-link:hover,
    .nav-link.active {
      color: var(--primary);
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width var(--transition);
    }
    .nav-link:hover::after {
      width: 100%;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      border-radius: var(--radius-md);
      padding: 12px 28px;
      font-weight: 600;
      font-size: 0.95rem;
      display: inline-flex;
      align-items: center;
      gap: 8px;
      box-shadow: 0 4px 10px rgba(26,95,220,0.2);
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      box-shadow: 0 8px 18px rgba(26,95,220,0.25);
      transform: translateY(-1px);
    }
    .btn-accent {
      background: var(--accent);
      color: white;
      border-radius: var(--radius-md);
      padding: 14px 32px;
      font-weight: 700;
      box-shadow: 0 6px 16px rgba(255,107,61,0.25);
    }
    .btn-accent:hover {
      background: var(--accent-hover);
      box-shadow: 0 10px 22px rgba(255,107,61,0.3);
      transform: translateY(-2px);
    }
    .btn-ghost {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      border-radius: var(--radius-md);
      padding: 12px 28px;
      font-weight: 600;
    }
    .btn-ghost:hover {
      background: var(--primary);
      color: white;
    }
    .hamburger {
      display: none;
      font-size: 1.8rem;
      color: var(--text-main);
    }
    /* Hero 双栏 */
    .hero {
      display: flex;
      align-items: center;
      gap: 60px;
      padding: 60px 0 80px;
      min-height: 550px;
    }
    .hero-left {
      flex: 1 1 50%;
    }
    .hero-right {
      flex: 1 1 50%;
      display: flex;
      justify-content: center;
    }
    .hero h1 {
      font-size: 3.5rem;
      font-weight: 800;
      line-height: 1.2;
      letter-spacing: -0.02em;
      margin-bottom: 24px;
      background: linear-gradient(to right, #0F172A, #1E3A8A);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .hero-sub {
      font-size: 1.2rem;
      color: var(--text-muted);
      max-width: 480px;
      margin-bottom: 36px;
      line-height: 1.7;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: var(--radius-xl);
      width: 100%;
      aspect-ratio: 4/3;
      box-shadow: 0 20px 35px rgba(0,0,0,0.12);
      transform: rotate(1deg);
      transition: transform 0.3s ease;
    }
    .hero-image:hover {
      transform: rotate(0deg) scale(1.01);
    }
    /* 通用板块标题 */
    .section-title {
      text-align: center;
      margin-bottom: 64px;
    }
    .section-title h2 {
      font-size: 2.4rem;
      font-weight: 700;
      background: linear-gradient(135deg, #0F172A 0%, #1A5FDC 90%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .section-sub {
      color: var(--text-muted);
      margin-top: 12px;
      font-size: 1.1rem;
    }
    /* 核心亮点 不对称网格 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .feature-card {
      background: var(--card-white);
      border-radius: var(--radius-lg);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      transition: all var(--transition);
    }
    .feature-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
    }
    .feature-card.large {
      grid-row: span 2;
      background: url('/assets/images/backpic/back-2.webp') center/cover no-repeat;
      position: relative;
      color: white;
      display: flex;
      flex-direction: column;
      justify-content: flex-end;
      min-height: 340px;
    }
    .feature-card.large::before {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(0deg, rgba(0,0,0,0.7) 0%, rgba(0,0,0,0.2) 80%);
      border-radius: var(--radius-lg);
    }
    .feature-card.large .content {
      position: relative;
      z-index: 2;
    }
    .feature-icon {
      font-size: 2.5rem;
      color: var(--primary);
      margin-bottom: 20px;
    }
    .feature-card h3 {
      font-size: 1.4rem;
      margin-bottom: 12px;
    }
    .feature-card p {
      color: var(--text-muted);
      line-height: 1.7;
    }
    /* 数据背书深色条 */
    .stats-band {
      background: #0F172A;
      border-radius: 32px;
      padding: 56px 48px;
      margin: 60px 0;
      display: flex;
      justify-content: space-around;
      text-align: center;
      color: white;
      background-image: radial-gradient(circle at 20% 30%, #1E293B 0%, #0F172A 90%);
    }
    .stat-item h3 {
      font-size: 2.8rem;
      font-weight: 800;
      color: var(--accent);
    }
    /* 案例瀑布流 */
    .solution-row {
      display: flex;
      align-items: center;
      gap: 48px;
      margin-bottom: 80px;
    }
    .solution-row.reverse {
      flex-direction: row-reverse;
    }
    .solution-img {
      flex: 1;
      border-radius: 20px;
      overflow: hidden;
      aspect-ratio: 4/3;
      box-shadow: var(--shadow-card);
    }
    .solution-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.4s ease;
    }
    .solution-img:hover img {
      transform: scale(1.04);
    }
    .solution-text {
      flex: 1;
    }
    .tag {
      background: rgba(26,95,220,0.1);
      color: var(--primary);
      padding: 6px 16px;
      border-radius: 20px;
      font-weight: 600;
      font-size: 0.8rem;
      display: inline-block;
      margin-bottom: 16px;
    }
    /* 方案对比 */
    .compare-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .plan-card {
      background: var(--card-white);
      border-radius: var(--radius-lg);
      padding: 40px 24px;
      text-align: center;
      box-shadow: var(--shadow-card);
      border: 2px solid transparent;
    }
    .plan-card.recommended {
      border-color: var(--accent);
      position: relative;
    }
    .badge {
      background: var(--accent);
      color: white;
      font-size: 0.8rem;
      font-weight: 700;
      padding: 4px 18px;
      border-radius: 20px;
      position: absolute;
      top: -14px;
      left: 50%;
      transform: translateX(-50%);
    }
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      font-weight: 600;
      font-size: 1.1rem;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-muted);
      padding-right: 20px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-top: 12px;
    }
    /* CTA */
    .cta-block {
      background: #EFF6FF;
      border-radius: 40px;
      padding: 70px;
      text-align: center;
      margin: 70px 0;
    }
    /* 页脚 */
    .footer {
      background: #0F172A;
      color: #CBD5E1;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    @media (max-width: 1024px) {
      .container { padding: 0 24px; }
      .features-grid { grid-template-columns: repeat(2,1fr); }
      .compare-grid { grid-template-columns: 1fr; }
    }
    @media (max-width: 768px) {
      .hamburger { display: block; }
      .nav-menu { display: none; position: fixed; top: var(--header-height); left: 0; width: 100%; background: white; flex-direction: column; padding: 30px; gap: 20px; box-shadow: 0 10px 20px rgba(0,0,0,0.05); }
      .nav-menu.active { display: flex; }
      .hero { flex-direction: column; text-align: center; }
      .hero h1 { font-size: 2.5rem; }
      .stats-band { flex-wrap: wrap; gap: 30px; }
      .solution-row, .solution-row.reverse { flex-direction: column; }
      .footer-grid { grid-template-columns: 1fr; }
    }