/* roulang page: index */
:root {
      --primary-green: #0A7E3E;
      --dark-black: #1A1A1A;
      --warm-gold: #D4A843;
      --bg-warm-white: #FAF9F6;
      --border-light: #E8E8E8;
      --text-dark: #1A1A1A;
      --text-muted: #5A5A5A;
      --white: #FFFFFF;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 30px rgba(0,0,0,0.08);
      --shadow-lg: 0 16px 40px rgba(0,0,0,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', 'Helvetica Neue', sans-serif;
      --transition-base: 0.3s ease;
      --container-max: 1200px;
      --nav-height: 72px;
    }

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

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-warm-white);
      color: var(--text-dark);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }

    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition-base);
    }

    button, .btn {
      cursor: pointer;
      font-family: var(--font-sans);
      font-weight: 600;
      border: none;
      outline: none;
      transition: var(--transition-base);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
    }

    /* 导航系统 —— 沉浸式 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      z-index: 1000;
      transition: background 0.3s ease, box-shadow 0.3s ease;
      background: transparent;
    }

    .site-header.scrolled {
      background: var(--bg-warm-white);
      box-shadow: 0 4px 20px rgba(0,0,0,0.06);
      backdrop-filter: blur(10px);
    }

    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
    }

    .logo {
      font-size: 1.8rem;
      font-weight: 700;
      letter-spacing: 1px;
      color: var(--white);
      display: flex;
      align-items: center;
      gap: 8px;
      transition: color 0.3s;
    }

    .site-header.scrolled .logo {
      color: var(--dark-black);
    }

    .logo-icon {
      font-size: 2rem;
      line-height: 1;
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
    }

    .nav-link {
      font-weight: 500;
      color: rgba(255,255,255,0.9);
      position: relative;
      font-size: 1rem;
      transition: color 0.3s;
    }

    .site-header.scrolled .nav-link {
      color: var(--text-dark);
    }

    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -6px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--warm-gold);
      transition: width 0.3s;
    }

    .nav-link:hover::after,
    .nav-link.active::after {
      width: 100%;
    }

    .nav-cta {
      background: var(--warm-gold);
      color: var(--dark-black);
      padding: 10px 24px;
      border-radius: 30px;
      font-weight: 600;
      transition: 0.3s;
      margin-left: 8px;
    }

    .site-header.scrolled .nav-cta {
      background: var(--primary-green);
      color: white;
    }

    .nav-cta:hover {
      opacity: 0.9;
      transform: translateY(-2px);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
      padding: 8px;
    }

    .hamburger span {
      width: 26px;
      height: 2px;
      background: white;
      transition: 0.3s;
      display: block;
    }

    .site-header.scrolled .hamburger span {
      background: var(--dark-black);
    }

    /* Hero 首屏 */
    .hero {
      height: 100vh;
      min-height: 700px;
      background: linear-gradient(135deg, rgba(10,30,20,0.75) 0%, rgba(0,0,0,0.7) 100%), url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      background-attachment: fixed;
      display: flex;
      align-items: center;
      justify-content: center;
      text-align: center;
      color: white;
      position: relative;
    }

    .hero-content {
      max-width: 900px;
      padding: 0 24px;
    }

    .hero h1 {
      font-size: clamp(2.8rem, 6vw, 4.2rem);
      font-weight: 700;
      line-height: 1.2;
      margin-bottom: 24px;
      color: var(--warm-gold);
      text-shadow: 0 4px 20px rgba(0,0,0,0.3);
    }

    .hero .subtitle {
      font-size: 1.3rem;
      color: rgba(255,255,255,0.9);
      margin-bottom: 40px;
      font-weight: 400;
      max-width: 700px;
      margin-left: auto;
      margin-right: auto;
    }

    .btn-primary {
      background: var(--warm-gold);
      color: var(--dark-black);
      padding: 14px 40px;
      border-radius: 30px;
      font-size: 1.1rem;
      font-weight: 700;
      letter-spacing: 0.5px;
      box-shadow: 0 8px 24px rgba(212,168,67,0.3);
    }

    .btn-primary:hover {
      background: #e6b84c;
      transform: translateY(-3px);
      box-shadow: 0 12px 28px rgba(212,168,67,0.4);
    }

    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary-green);
      color: var(--primary-green);
      padding: 12px 28px;
      border-radius: 30px;
      font-weight: 600;
    }

    .btn-outline:hover {
      background: var(--primary-green);
      color: white;
    }

    section {
      padding: 100px 0;
    }

    .section-title {
      font-size: 2.4rem;
      font-weight: 700;
      margin-bottom: 16px;
      color: var(--dark-black);
      text-align: center;
    }

    .section-sub {
      color: var(--text-muted);
      text-align: center;
      max-width: 700px;
      margin: 0 auto 48px;
      font-size: 1.1rem;
    }

    /* 核心优势 —— 打破对称，图文错落 */
    .advantages-grid {
      display: flex;
      flex-wrap: wrap;
      gap: 40px;
      align-items: center;
      justify-content: center;
    }

    .adv-item {
      display: flex;
      align-items: center;
      gap: 32px;
      background: white;
      border-radius: 20px;
      padding: 24px;
      box-shadow: var(--shadow-sm);
      transition: var(--transition-base);
      flex: 1 1 400px;
    }

    .adv-item:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-6px);
    }

    .adv-icon {
      font-size: 3rem;
      background: #f0f7f2;
      width: 80px;
      height: 80px;
      display: flex;
      align-items: center;
      justify-content: center;
      border-radius: 20px;
      color: var(--primary-green);
    }

    .adv-text h3 {
      font-size: 1.5rem;
      margin-bottom: 8px;
    }

    /* 功能分组左右交替 */
    .feature-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }

    .feature-row.reverse {
      flex-direction: row-reverse;
    }

    .feature-img {
      flex: 1;
      border-radius: 20px;
      overflow: hidden;
      box-shadow: var(--shadow-md);
      background: #ddd;
    }

    .feature-img img {
      width: 100%;
      height: auto;
      object-fit: cover;
    }

    .feature-text {
      flex: 1;
    }

    .feature-text h3 {
      font-size: 2rem;
      margin-bottom: 16px;
      color: var(--dark-black);
    }

    .tag {
      background: #f0f7f2;
      color: var(--primary-green);
      padding: 4px 14px;
      border-radius: 30px;
      font-size: 0.85rem;
      font-weight: 600;
      display: inline-block;
      margin-bottom: 12px;
    }

    .scene-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 32px;
    }

    .scene-card {
      background: white;
      border-radius: 20px;
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: var(--transition-base);
    }

    .scene-card:hover {
      box-shadow: var(--shadow-lg);
      transform: translateY(-8px);
    }

    .scene-card img {
      width: 100%;
      height: 200px;
      object-fit: cover;
    }

    .scene-body {
      padding: 24px;
    }

    .stats-scroll {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      padding: 20px 0;
      scroll-snap-type: x mandatory;
    }

    .stat-card {
      min-width: 220px;
      background: white;
      padding: 28px;
      border-radius: 20px;
      text-align: center;
      box-shadow: var(--shadow-sm);
      scroll-snap-align: start;
    }

    .stat-number {
      font-size: 2.8rem;
      font-weight: 700;
      color: var(--warm-gold);
    }

    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
    }

    .faq-question {
      font-weight: 600;
      font-size: 1.2rem;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-muted);
      padding-right: 30px;
    }

    .faq-item.active .faq-answer {
      max-height: 200px;
      margin-top: 12px;
    }

    .cta-band {
      background: var(--dark-black);
      color: white;
      text-align: center;
      padding: 80px 24px;
      border-radius: 32px;
      margin: 60px 0;
    }

    footer {
      background: var(--dark-black);
      color: #ccc;
      padding: 60px 0 30px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 40px;
    }

    @media (max-width: 992px) {
      .feature-row {
        flex-direction: column;
        gap: 32px;
      }
    }

    @media (max-width: 768px) {
      .hamburger {
        display: flex;
      }
      .nav-menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 80%;
        height: 100vh;
        background: var(--dark-black);
        flex-direction: column;
        justify-content: center;
        gap: 40px;
        transition: 0.4s;
      }
      .nav-menu.open {
        right: 0;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }