/* roulang page: index */
/* ----- 设计变量及基础reset ----- */
    :root {
      --primary: #1A5F7A;
      --primary-dark: #134B5F;
      --accent-cyan: #0E9AA7;
      --cta-orange: #F47521;
      --cta-orange-dark: #E06512;
      --bg-page: #F8FAFC;
      --bg-white: #FFFFFF;
      --gray-border: #E2E8F0;
      --text-heading: #1E293B;
      --text-body: #334155;
      --text-muted: #64748B;
      --text-on-dark: #F1F5F9;
      --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06), 0 1px 2px rgba(0, 0, 0, 0.04);
      --shadow-hover: 0 10px 25px rgba(0, 0, 0, 0.08);
      --adapt-share: both;
      --ctanomal-scale: twe");
    }

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

    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }

    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui, "Inter", sans-serif;
      background-color: var(--bg-page);
      color: var(--text-body);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.25s ease, background 0.25s ease;
    }

    h1, h2, h3 {
      font-weight: 600;
      color: var(--text-heading);
    }

    h1 {
      font-size: clamp(2.25rem, 5vw, 2.75rem);
      line-height: 1.25;
      letter-spacing: -0.5px;
      font-weight: 700;
    }

    h2 {
      font-size: clamp(1.8rem, 4vw, 2.2rem);
      line-height: 1.3;
    }

    h3 {
      font-size: 1.3rem;
      font-weight: 600;
      line-height: 1.4;
    }

    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
      width: 100%;
    }

    section {
      padding: 5rem 0;
    }

    @media (max-width: 768px) {
      section {
        padding: 3.125rem 0;
      }
    }

    /* ----- 导航 (白底平台, 滚动阴影) ----- */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255, 255, 255, 0.96);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid transparent;
      transition: box-shadow 0.3s ease, border-color 0.3s ease;
    }
    .site-header.scrolled {
      box-shadow: 0 2px 12px rgba(0,0,0,0.06);
      border-bottom-color: var(--gray-border);
    }

    .nav-bar {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 0.8rem 0;
      height: 72px;
    }

    .logo {
      display: flex;
      align-items: center;
      gap: 0.5rem;
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--primary);
      letter-spacing: -0.3px;
    }
    .logo-icon {
      width: 36px;
      height: 36px;
      background: linear-gradient(135deg, var(--accent-cyan), var(--primary));
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 1.2rem;
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 2rem;
      list-style: none;
      white-space: nowrap;
      font-weight: 500;
      color: var(--text-heading);
    }

    .nav-links a {
      position: relative;
      padding-bottom: 0.2rem;
      font-size: 0.975rem;
      letter-spacing: 0.2px;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: -2px;
      width: 0%;
      height: 2px;
      background: var(--primary);
      transition: width 0.25s ease;
    }
    .nav-links a:hover {
      color: var(--primary);
    }
    .nav-links a.active, .nav-links a:hover::after {
      width: 100%;
    }

    .nav-cta {
      background: var(--cta-orange);
      color: white;
      padding: 0.6rem 1.5rem;
      border-radius: 8px;
      font-weight: 600;
      transition: all 0.25s;
      font-size: 0.9rem;
    }
    .nav-cta:hover {
      background: var(--cta-orange-dark);
      color: white;
    }

    .hamburger {
      display: none;
      flex-direction: column;
      cursor: pointer;
      gap: 5px;
    }
    .hamburger span {
      background: var(--text-heading);
      height: 2.5px;
      width: 24px;
      border-radius: 4px;
      transition: 0.3s;
    }

    @media (max-width: 1024px) {
      .hamburger {
        display: flex;
      }
      .nav-links {
        position: absolute;
        top: 72px;
        left: 0;
        width: 100%;
        flex-direction: column;
        background: white;
        padding: 1.5rem 20px;
        gap: 1.8rem;
        box-shadow: var(--shadow-sm);
        transform: translateY(-120%);
        opacity: 0;
        transition: all 0.35s ease;
        pointer-events: none;
      }
      .nav-links.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: auto;
      }
    }

    /* ----- 按钮通用色 ----- */
    .btn-primary {
      background: var(--primary);
      color: white;
      border-radius: 8px;
      padding: 0.9rem 2rem;
      font-weight: 600;
      display: inline-block;
      transition: 0.25s ease;
      border: none;
      cursor: pointer;
      text-align: center;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: scale(1.02);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      border-radius: 8px;
      padding: 0.8rem 1.8rem;
      font-weight: 600;
      transition: 0.25s;
    }
    .btn-outline:hover {
      background: rgba(26,95,122,0.08);
      color: var(--primary);
    }
    .btn-accent {
      background: var(--cta-orange);
      color: white;
      border-radius: 8px;
      padding: 0.9rem 2.1rem;
      font-weight: 700;
      transition: 0.25s;
      display: inline-block;
      border: none;
      cursor: pointer;
    }
    .btn-accent:hover {
      background: var(--cta-orange-dark);
      transform: scale(1.02);
      color: white;
    }

    /* ----- 页面板块区隔 ----- */
    .section-head {
      text-align: center;
      margin-bottom: 3rem;
    }
    .section-head h2 {
      margin-bottom: 0.8rem;
      color: var(--text-heading);
    }
    .section-head p {
      color: var(--text-muted);
      font-size: 1.125rem;
      max-width: 700px;
      margin: 0 auto;
    }
    .gray-bg {
      background: #f1f5f9;
    }

    /* hero网格 */
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1.1fr;
      gap: 3rem;
      align-items: center;
    }
    .hero-text {
      position: relative;
      padding-left: 1.5rem;
      border-left: 5px solid var(--accent-cyan);
    }
    .hero-text h1 {
      margin-bottom: 1.5rem;
      color: var(--text-heading);
    }
    .hero-sub {
      font-size: 1.2rem;
      color: #475569;
      margin: 1.2rem 0 2rem;
    }
    .hero-img img {
      border-radius: 24px;
      box-shadow: var(--shadow-hover);
      transition: transform 0.3s;
      width: 100%;
    }

    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
      }
      .hero-text {
        border-left: none;
        padding-left: 0;
        text-align: center;
      }
    }

    .stats-row {
      display: flex;
      justify-content: space-around;
      flex-wrap: wrap;
      gap: 1.8rem;
      margin-top: 2rem;
    }
    .stat-item {
      text-align: center;
    }
    .stat-number {
      font-size: 2.5rem;
      font-weight: 700;
      color: var(--cta-orange);
    }

    .card-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 2rem;
    }
    .card {
      background: var(--bg-white);
      border-radius: 16px;
      padding: 2rem 1.5rem;
      box-shadow: var(--shadow-sm);
      transition: all 0.25s ease;
    }
    .card:hover {
      transform: translateY(-5px);
      box-shadow: var(--shadow-hover);
    }
    .card img {
      width: 100%;
      height: 180px;
      object-fit: cover;
      border-radius: 12px;
      margin-bottom: 1.5rem;
    }
    @media (max-width: 1024px) {
      .card-grid { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 640px) {
      .card-grid { grid-template-columns: 1fr; }
    }

    .scenario-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 2.5rem;
    }
    .scenario-item {
      background: white;
      border-radius: 20px;
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      display: flex;
      flex-direction: column;
    }
    .scenario-item img {
      height: 220px;
      object-fit: cover;
      width: 100%;
    }
    @media (max-width: 768px) {
      .scenario-grid { grid-template-columns: 1fr; }
    }

    /* FAQ 手风琴 */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--gray-border);
    }
    .faq-question {
      width: 100%;
      background: white;
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 1.2rem 0.5rem;
      font-weight: 600;
      cursor: pointer;
      border: none;
      font-size: 1rem;
      color: var(--text-heading);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      background: #f8fafc;
      padding: 0 1rem;
    }
    .faq-answer p {
      padding: 0.8rem 0;
      color: var(--text-muted);
    }

    /* CTA区域 */
    .cta-block {
      background: var(--primary);
      color: white;
      border-radius: 28px;
      padding: 4rem 2rem;
      text-align: center;
    }
    .cta-block h2 {
      color: white;
      margin-bottom: 1rem;
    }

    footer {
      background: #0F172A;
      color: #cbd5e1;
      padding: 2.5rem 20px;
    }
    
    @media (max-width: 480px) {
      .btn-group { display: flex; flex-direction: column; gap: 1rem; }
    }