/* roulang page: index */
:root {
      --primary-deep: #0A2E1F;
      --accent-glow: #00E676;
      --warm-orange: #FF6D3A;
      --bg-paper: #F4F6F0;
      --white: #FFFFFF;
      --text-dark: #1A1A1A;
      --text-mute: #5C6B63;
      --shadow-card: 0 4px 20px rgba(10, 46, 31, 0.06);
      --shadow-hover: 0 8px 30px rgba(10, 46, 31, 0.12);
      --radius-lg: 24px;
      --radius-card: 12px;
      --radius-btn: 30px;
      --transition-main: 0.25s ease;
      --font-heavy: 'PingFang SC Heavy', 'Noto Sans SC Bold', 'Microsoft YaHei', sans-serif;
      --font-regular: 'PingFang SC Regular', 'Noto Sans SC', 'Microsoft YaHei', sans-serif;
    }

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

    body {
      font-family: var(--font-regular);
      background-color: var(--white);
      color: var(--text-dark);
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
      scroll-behavior: smooth;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: transparent;
    }

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

    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 100;
      transition: background 0.3s, backdrop-filter 0.3s, box-shadow 0.3s;
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(12px);
      box-shadow: 0 4px 20px rgba(0,0,0,0.03);
      height: 68px;
      display: flex;
      align-items: center;
    }

    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }

    .logo {
      font-family: var(--font-heavy);
      font-size: 1.6rem;
      font-weight: 800;
      color: var(--primary-deep);
      letter-spacing: -0.3px;
      display: flex;
      align-items: center;
      gap: 6px;
    }

    .logo-icon {
      display: inline-flex;
      width: 30px;
      height: 28px;
      background: linear-gradient(135deg, #00E676 10%, #0A2E1F 80%);
      mask: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 20"><path d="M12 2L2 18h7v-6l3 4 3-4v6h7L12 2z" fill="white"/></svg>') center/contain no-repeat;
      background-size: cover;
      transform: rotate(-5deg);
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 36px;
    }

    .nav-links a {
      font-weight: 600;
      font-size: 0.98rem;
      color: var(--text-dark);
      position: relative;
      padding: 4px 0;
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--accent-glow);
      transition: width 0.25s ease;
    }

    .nav-links a:hover::after {
      width: 100%;
    }

    .nav-cta {
      background: var(--accent-glow);
      color: var(--primary-deep);
      font-weight: 700;
      padding: 10px 22px;
      border-radius: var(--radius-btn);
      font-size: 0.95rem;
      box-shadow: 0 2px 10px rgba(0,230,118,0.25);
      margin-left: 16px;
    }

    .nav-cta:hover {
      background: #00ff84;
      box-shadow: 0 0 16px rgba(0,230,118,0.5);
    }

    .mobile-menu-btn {
      display: none;
      background: none;
      border: none;
      font-size: 1.8rem;
      color: var(--primary-deep);
    }

    /* 底部移动导航 */
    .bottom-mobile-nav {
      display: none;
    }

    /* Hero */
    .hero {
      background-color: var(--primary-deep);
      min-height: 100vh;
      display: flex;
      align-items: center;
      padding-top: 70px;
      position: relative;
      overflow: hidden;
    }

    .hero .container {
      display: flex;
      align-items: center;
      gap: 40px;
      width: 100%;
      position: relative;
      z-index: 2;
    }

    .hero-content {
      flex: 1 1 50%;
    }

    .hero-title {
      font-family: var(--font-heavy);
      font-size: clamp(2.7rem, 6vw, 4.7rem);
      font-weight: 900;
      line-height: 1.12;
      letter-spacing: -0.02em;
      color: white;
      margin-bottom: 24px;
    }

    .hero-sub {
      font-size: 1.2rem;
      color: rgba(255,255,255,0.85);
      margin-bottom: 36px;
      max-width: 460px;
    }

    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }

    .btn-primary {
      background: var(--accent-glow);
      color: var(--primary-deep);
      font-weight: 700;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-size: 1.07rem;
      box-shadow: 0 6px 18px rgba(0,230,118,0.3);
      transition: 0.25s;
    }

    .btn-primary:hover {
      background: #00ff8c;
      box-shadow: 0 0 20px rgba(0,230,118,0.6);
      transform: translateY(-2px);
    }

    .btn-outline {
      background: transparent;
      border: 1.5px solid white;
      color: white;
      font-weight: 600;
      padding: 13px 32px;
      border-radius: var(--radius-btn);
    }

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

    .hero-visual {
      flex: 1 1 48%;
      position: relative;
    }

    .hero-visual img {
      border-radius: 40px 8px 40px 8px;
      box-shadow: 0 20px 35px rgba(0,0,0,0.5);
      z-index: 2;
      position: relative;
      width: 100%;
    }

    .speed-lines {
      position: absolute;
      top: 20px;
      right: -18px;
      width: 250px;
      height: 250px;
      background: repeating-linear-gradient(45deg, rgba(255,255,255,0.06) 0px, rgba(255,255,255,0.06) 2px, transparent 3px, transparent 8px);
    }

    /* 板块通用 */
    section {
      padding: 100px 0;
    }

    .section-title {
      font-family: var(--font-heavy);
      font-size: 2.2rem;
      font-weight: 700;
      color: var(--primary-deep);
      margin-bottom: 16px;
      letter-spacing: -0.3px;
    }

    .section-sub {
      color: var(--text-mute);
      margin-bottom: 48px;
    }

    /* 核心优势 非对称 2+1 */
    .advantages-grid {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }

    .wide-card {
      flex: 0 0 calc(66.666% - 14px);
      background: #EEF4EC;
      border-radius: 24px;
      padding: 36px 30px;
      display: flex;
      flex-direction: column;
      justify-content: center;
    }

    .small-cards {
      flex: 0 0 calc(33.333% - 10px);
      display: flex;
      flex-direction: column;
      gap: 20px;
    }

    .small-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 26px 22px;
      box-shadow: var(--shadow-card);
      transition: var(--transition-main);
    }

    .small-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }

    .icon-accent {
      color: var(--accent-glow);
      font-size: 2rem;
      margin-bottom: 15px;
    }

    /* 功能分组交替 */
    .feature-row {
      display: flex;
      align-items: center;
      gap: 48px;
      margin-bottom: 80px;
    }

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

    .feature-text {
      flex: 1;
    }

    .feature-img {
      flex: 1;
      border-radius: 60px 8px 60px 8px;
      overflow: hidden;
    }

    .feature-img img {
      border-radius: inherit;
    }

    /* 场景卡片 */
    .scene-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .scene-card {
      position: relative;
      border-radius: 18px;
      overflow: hidden;
      height: 320px;
    }

    .scene-card img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      filter: brightness(0.7);
    }

    .scene-caption {
      position: absolute;
      bottom: 25px;
      left: 25px;
      color: white;
      font-weight: 700;
      font-size: 1.4rem;
    }

    /* 数据区 */
    .stats-bar {
      display: flex;
      justify-content: space-around;
      background: #fff;
      border-radius: 20px;
      padding: 40px 20px;
      box-shadow: var(--shadow-card);
    }

    .stat-item {
      text-align: center;
    }

    .stat-number {
      font-size: 3rem;
      font-weight: 800;
      color: var(--warm-orange);
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid #e0e6dd;
      padding: 18px 0;
    }
    .faq-question {
      font-weight: 700;
      font-size: 1.1rem;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: 0.3s;
      color: var(--text-mute);
    }
    .faq-item.active .faq-answer {
      max-height: 160px;
      margin-top: 10px;
    }

    .cta-full {
      background: var(--primary-deep);
      text-align: center;
      color: white;
      border-radius: 30px;
      padding: 70px 30px;
    }

    footer {
      background: var(--primary-deep);
      color: #ddd;
      padding: 60px 0 30px;
    }

    @media (max-width: 1024px) {
      .advantages-grid {
        flex-direction: column;
      }
      .wide-card, .small-cards {
        flex: auto;
      }
    }

    @media (max-width: 768px) {
      .desktop-nav {
        display: none;
      }
      .mobile-menu-btn {
        display: block;
      }
      .bottom-mobile-nav {
        display: flex;
        position: fixed;
        bottom: 0;
        left: 0;
        width: 100%;
        background: white;
        justify-content: space-around;
        padding: 8px 10px;
        box-shadow: 0 -5px 15px rgba(0,0,0,0.05);
        z-index: 99;
        border-radius: 20px 20px 0 0;
      }
      .bottom-mobile-nav a {
        font-size: 0.8rem;
        font-weight: 600;
        color: var(--primary-deep);
      }
      .hero .container {
        flex-direction: column;
      }
      .feature-row, .feature-row.reverse {
        flex-direction: column;
      }
      .scene-grid {
        grid-template-columns: 1fr;
      }
      .stats-bar {
        flex-wrap: wrap;
        gap: 20px;
      }
      section {
        padding: 70px 0;
      }
    }