/* roulang page: index */
/* ----- 设计变量 & 基础重置 ----- */
    :root {
      --primary: #0A2540;
      --accent: #00C2A8;
      --bg: #FAFBFD;
      --card-bg: #FFFFFF;
      --text: #1E2A38;
      --text-secondary: #5F6B7A;
      --border-light: #E6ECF2;
      --shadow-sm: 0 1px 3px rgba(10,37,64,0.04), 0 6px 16px rgba(10,37,64,0.06);
      --shadow-hover: 0 12px 28px rgba(10,37,64,0.1);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-pill: 40px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --font-number: "Inter", system-ui;
      --container-max: 1280px;
      --section-gap: 120px;
      --transition: 0.25s ease;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 32px;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    img {
      max-width: 100%;
      display: block;
      height: auto;
    }
    button, .btn {
      cursor: pointer;
      font-family: var(--font-sans);
      border: none;
      background: none;
    }
    /* 标题层级 */
    h2 {
      font-size: 40px;
      font-weight: 600;
      line-height: 1.3;
      letter-spacing: -0.01em;
      margin-bottom: 16px;
    }
    h3 {
      font-size: 22px;
      font-weight: 600;
      line-height: 1.4;
      margin-bottom: 8px;
    }
    /* 辅助类 */
    .text-accent {
      color: var(--accent);
    }
    .text-secondary {
      color: var(--text-secondary);
    }
    /* 按钮系统 */
    .btn-primary {
      background-color: var(--accent);
      color: white;
      font-weight: 600;
      font-size: 16px;
      letter-spacing: 0.04em;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      transition: background-color var(--transition), transform var(--transition), box-shadow var(--transition);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      min-width: 44px;
      min-height: 44px;
      box-shadow: 0 2px 6px rgba(0,194,168,0.25);
    }
    .btn-primary:hover {
      background-color: #00A894;
      transform: translateY(-1px);
      box-shadow: 0 6px 14px rgba(0,194,168,0.35);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      font-weight: 600;
      font-size: 16px;
      letter-spacing: 0.04em;
      padding: 12px 30px;
      border-radius: var(--radius-btn);
      transition: all var(--transition);
      min-width: 44px;
      min-height: 44px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }
    .btn-outline:hover {
      background-color: rgba(10,37,64,0.08);
      border-color: var(--primary);
    }
    .btn-text {
      color: var(--accent);
      font-weight: 500;
      font-size: 15px;
      text-decoration: underline;
      transition: opacity var(--transition);
    }
    .btn-text:hover {
      opacity: 0.8;
      text-decoration: none;
    }
    .btn-large {
      padding: 18px 48px;
      font-size: 18px;
      border-radius: var(--radius-pill);
    }
    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(10px);
      z-index: 90;
      transition: box-shadow 0.3s ease, background 0.3s;
    }
    .site-header.scrolled {
      box-shadow: 0 2px 12px rgba(0,0,0,0.04);
      background: rgba(255,255,255,0.96);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 32px;
    }
    .logo {
      font-size: 26px;
      font-weight: 700;
      color: var(--primary);
      display: flex;
      align-items: baseline;
      gap: 4px;
      letter-spacing: -0.3px;
    }
    .logo-dot {
      color: var(--accent);
      font-size: 32px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 36px;
      font-weight: 500;
      font-size: 15px;
      color: var(--text);
    }
    .nav-links a {
      position: relative;
      padding: 8px 0;
      transition: color 0.2s;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent);
      transition: width 0.25s;
    }
    .nav-links a:hover, .nav-links a.active {
      color: var(--primary);
    }
    .nav-links a.active::after, .nav-links a:hover::after {
      width: 100%;
    }
    .nav-cta {
      margin-left: 24px;
    }
    .hamburger {
      display: none;
      font-size: 24px;
      color: var(--primary);
      background: none;
      border: none;
    }
    /* 移动端导航抽屉 */
    .mobile-menu {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: white;
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 28px;
      z-index: 100;
      transform: translateY(-100%);
      transition: transform 0.4s cubic-bezier(0.2,0.9,0.3,1);
    }
    .mobile-menu.open {
      transform: translateY(0);
    }
    .mobile-menu a {
      font-size: 22px;
      font-weight: 600;
    }
    .close-menu {
      position: absolute;
      top: 24px;
      right: 32px;
      font-size: 28px;
      background: none;
      border: none;
    }
    /* 各部分间距 */
    section {
      padding: var(--section-gap) 0;
    }
    @media (max-width: 1023px) {
      section {
        padding: 80px 0;
      }
      h2 {
        font-size: 34px;
      }
    }
    @media (max-width: 767px) {
      section {
        padding: 64px 0;
      }
      h2 {
        font-size: 28px;
      }
      .container {
        padding: 0 20px;
      }
    }
    /* Hero */
    .hero-grid {
      display: grid;
      grid-template-columns: 5fr 7fr;
      gap: 56px;
      align-items: center;
      margin-top: 40px;
    }
    .hero-left h1 {
      font-size: 56px;
      font-weight: 700;
      line-height: 1.15;
      letter-spacing: -0.02em;
      margin-bottom: 20px;
    }
    .hero-left .subtitle {
      font-size: 18px;
      line-height: 1.6;
      color: var(--text-secondary);
      margin-bottom: 32px;
      max-width: 85%;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      margin-bottom: 28px;
    }
    .micro-stats {
      display: flex;
      gap: 28px;
      font-size: 13px;
      color: var(--text-secondary);
      font-weight: 500;
      border-top: 1px solid var(--border-light);
      padding-top: 24px;
    }
    .hero-right {
      position: relative;
    }
    .hero-right img {
      width: 100%;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      aspect-ratio: 4/3;
      object-fit: cover;
    }
    .hero-tag {
      position: absolute;
      bottom: 24px;
      right: 24px;
      background: white;
      padding: 12px 20px;
      border-radius: 20px;
      font-weight: 600;
      font-size: 14px;
      box-shadow: var(--shadow-sm);
      background: rgba(255,255,255,0.9);
    }
    @media (max-width: 1023px) {
      .hero-grid {
        gap: 40px;
      }
      .hero-left h1 {
        font-size: 44px;
      }
    }
    @media (max-width: 767px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 32px;
      }
      .hero-left h1 {
        font-size: 36px;
      }
      .micro-stats {
        flex-wrap: wrap;
      }
      .hero-buttons {
        flex-direction: column;
        width: 100%;
      }
    }
    /* 核心亮点网格 (2x3 mixed) */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      margin-top: 48px;
    }
    .feature-item {
      background: var(--card-bg);
      padding: 32px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .feature-item.wide {
      grid-column: span 2;
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .feature-item.wide img {
      width: 45%;
      border-radius: var(--radius-card);
      object-fit: cover;
      height: 180px;
    }
    .feature-item:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .feature-icon {
      font-size: 36px;
      color: var(--accent);
      margin-bottom: 16px;
    }
    @media (max-width: 1023px) {
      .features-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .feature-item.wide {
        grid-column: span 2;
      }
    }
    @media (max-width: 767px) {
      .features-grid {
        grid-template-columns: 1fr;
      }
      .feature-item.wide {
        grid-column: span 1;
        flex-direction: column;
      }
      .feature-item.wide img {
        width: 100%;
        height: auto;
      }
    }
    /* 瀑布流方案 */
    .waterfall {
      columns: 3;
      column-gap: 24px;
      margin-top: 48px;
    }
    .program-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 32px;
      margin-bottom: 24px;
      break-inside: avoid;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .program-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .program-card img {
      width: 100%;
      border-radius: 12px;
      margin: 16px 0;
    }
    .bullet-list {
      list-style: none;
      margin: 16px 0;
    }
    .bullet-list li::before {
      content: "●";
      color: var(--accent);
      font-size: 14px;
      margin-right: 8px;
    }
    @media (max-width: 1023px) {
      .waterfall {
        columns: 2;
      }
    }
    @media (max-width: 767px) {
      .waterfall {
        columns: 1;
      }
    }
    /* 对比表 */
    .compare-table {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 0;
      margin-top: 48px;
      background: white;
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
    }
    .col {
      padding: 32px;
      border-right: 1px solid var(--border-light);
    }
    .col:last-child { border-right: none; }
    .col.highlight {
      background: #F4F8FC;
      border-top: 4px solid var(--accent);
      border-radius: 12px 12px 0 0;
    }
    .col h3 { margin-bottom: 20px; }
    .feature-row {
      display: flex;
      justify-content: space-between;
      padding: 14px 0;
      border-bottom: 1px solid var(--border-light);
    }
    .check { color: var(--accent); font-weight: 700; }
    @media (max-width: 1023px) {
      .compare-table {
        overflow-x: auto;
        display: flex;
      }
      .col {
        min-width: 240px;
        flex: 1;
      }
    }
    /* 数据带 */
    .trust-bar {
      background: rgba(10,37,64,0.03);
      border-radius: 32px;
      margin: 48px 0;
      padding: 48px 32px;
      display: flex;
      justify-content: space-around;
      flex-wrap: wrap;
      text-align: center;
    }
    .stat-number {
      font-family: var(--font-number);
      font-size: 48px;
      font-weight: 700;
      color: var(--accent);
    }
    /* FAQ */
    .faq-layout {
      display: grid;
      grid-template-columns: 200px 1fr;
      gap: 48px;
    }
    .faq-categories button {
      display: block;
      background: none;
      border: none;
      padding: 10px 0;
      font-weight: 500;
      color: var(--text-secondary);
    }
    .faq-categories button.active {
      color: var(--accent);
      font-weight: 700;
    }
    .accordion-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
    }
    .accordion-question {
      display: flex;
      justify-content: space-between;
      font-weight: 600;
      cursor: pointer;
    }
    @media (max-width: 767px) {
      .faq-layout {
        grid-template-columns: 1fr;
      }
      .faq-categories {
        display: flex;
        overflow-x: auto;
        gap: 12px;
      }
    }
    /* CTA Banner */
    .cta-banner {
      background: linear-gradient(135deg, rgba(10,37,64,0.03) 0%, rgba(0,194,168,0.08) 100%);
      padding: 80px 20px;
      text-align: center;
      border-radius: 32px;
      margin-top: 60px;
    }
    /* 页脚 */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.2fr;
      gap: 40px;
      padding: 64px 0;
      background: var(--primary);
      color: #D0D8E4;
      border-radius: 20px 20px 0 0;
    }
    .footer-grid a { color: inherit; }
    .footer-bottom {
      text-align: center;
      padding: 24px;
      background: #091a2e;
      color: #8b99aa;
    }
    @media (max-width: 767px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }