/* roulang page: index */
:root {
      --brand-green: #0AE08E;
      --brand-green-hover: #06B878;
      --deep-green: #0A2E1F;
      --warm-white: #F7F8F6;
      --charcoal: #1E1E1E;
      --gray-text: #4B5563;
      --light-gray: #A0B0A8;
      --border-light: rgba(0,0,0,0.04);
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-img: 16px;
      --space-section: 96px;
      --space-card-padding: 32px;
      --transition-smooth: 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
      --font-hero: 56px;
      --font-h2: 40px;
      --font-h3: 20px;
      --font-body: 16px;
    }

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

    body {
      font-family: "Inter", "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui, sans-serif;
      background-color: var(--warm-white);
      color: var(--charcoal);
      line-height: 1.7;
      font-size: var(--font-body);
      -webkit-font-smoothing: antialiased;
    }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
    }

    /* 导航 */
    .main-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: rgba(255,255,255,0);
      transition: background 0.3s, backdrop-filter 0.3s, box-shadow 0.3s;
      border-bottom: 1px solid transparent;
    }
    .main-header.scrolled {
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(0,0,0,0.05);
      box-shadow: 0 4px 20px rgba(0,0,0,0.03);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 24px;
      color: var(--deep-green);
      letter-spacing: 1px;
    }
    .logo-icon {
      width: 36px;
      height: 36px;
      background: var(--brand-green);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 20px;
    }
    .main-header.scrolled .logo {
      color: var(--deep-green);
    }
    .nav-links {
      display: flex;
      gap: 40px;
      align-items: center;
      list-style: none;
    }
    .nav-links a {
      font-weight: 500;
      color: white;
      opacity: 0.9;
      font-size: 16px;
    }
    .main-header.scrolled .nav-links a {
      color: var(--charcoal);
    }
    .nav-links a:hover {
      opacity: 1;
      color: var(--brand-green);
    }
    .btn-primary {
      background: var(--brand-green);
      color: white;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      border: none;
      transition: background 0.25s ease, transform 0.2s;
    }
    .btn-primary:hover {
      background: var(--brand-green-hover);
      transform: scale(1.02);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--brand-green);
      color: var(--brand-green);
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: all 0.25s ease;
    }
    .btn-outline:hover {
      background: var(--brand-green);
      color: white;
    }
    .btn-white {
      background: white;
      color: var(--deep-green);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      border: none;
      transition: background 0.25s, transform 0.2s;
    }
    .btn-white:hover {
      background: #f0f0f0;
      transform: scale(1.02);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      padding: 10px;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: white;
      transition: 0.3s;
    }
    .main-header.scrolled .hamburger span {
      background: var(--charcoal);
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: var(--deep-green);
      z-index: 999;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 32px;
    }
    .mobile-menu a {
      color: white;
      font-size: 24px;
      font-weight: 600;
    }

    /* Hero */
    .hero {
      min-height: 100vh;
      background: var(--deep-green);
      display: flex;
      align-items: center;
      color: white;
      position: relative;
      overflow: hidden;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1.2fr 0.9fr;
      gap: 60px;
      align-items: center;
    }
    .hero-title {
      font-size: var(--font-hero);
      font-weight: 700;
      line-height: 1.2;
      margin-bottom: 24px;
      animation: fadeUp 0.6s ease;
    }
    .hero-sub {
      font-size: 20px;
      opacity: 0.9;
      margin-bottom: 40px;
      line-height: 1.6;
    }
    .hero-buttons {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }
    .hero-mockup {
      position: relative;
      animation: float 3s infinite ease-in-out;
    }
    .hero-mockup img {
      border-radius: 32px;
      box-shadow: 0 25px 50px rgba(0,0,0,0.4);
    }
    @keyframes float {
      0% { transform: translateY(0); }
      50% { transform: translateY(-6px); }
      100% { transform: translateY(0); }
    }
    @keyframes fadeUp {
      from { opacity: 0; transform: translateY(20px); }
      to { opacity: 1; transform: translateY(0); }
    }

    /* section 通用 */
    .section {
      padding: var(--space-section) 0;
    }
    .section-title {
      font-size: var(--font-h2);
      font-weight: 600;
      line-height: 1.3;
      margin-bottom: 16px;
      color: var(--charcoal);
    }
    .section-desc {
      color: var(--gray-text);
      max-width: 600px;
      margin-bottom: 48px;
    }

    /* 卡片网格 */
    .card-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .card {
      background: white;
      border-radius: var(--radius-card);
      padding: var(--space-card-padding);
      border: 1px solid var(--border-light);
      box-shadow: var(--shadow-sm);
      transition: var(--transition-smooth);
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .card-icon {
      font-size: 40px;
      margin-bottom: 20px;
      color: var(--brand-green);
    }
    .card h3 {
      font-size: var(--font-h3);
      font-weight: 600;
      margin-bottom: 12px;
    }
    .card p {
      color: var(--gray-text);
      font-size: 14px;
    }

    /* 场景交替 */
    .scene-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
      margin-bottom: 80px;
    }
    .scene-img img {
      border-radius: var(--radius-img);
      box-shadow: var(--shadow-md);
    }
    .scene-text h3 {
      font-size: 28px;
      margin-bottom: 16px;
    }
    .scene-text ul {
      margin-top: 20px;
      list-style: none;
    }
    .scene-text li::before {
      content: "✓";
      color: var(--brand-green);
      margin-right: 12px;
      font-weight: bold;
    }

    /* 数据卡 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }
    .stat-card {
      background: #fff;
      padding: 40px 32px;
      border-radius: var(--radius-card);
      text-align: center;
      transition: 0.2s;
    }
    .stat-number {
      font-size: 48px;
      font-weight: 700;
      color: var(--brand-green);
    }
    .stat-label {
      color: var(--gray-text);
      margin-top: 12px;
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid rgba(0,0,0,0.08);
      padding: 24px 0;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      font-weight: 600;
      font-size: 18px;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--gray-text);
    }
    .faq-answer.open {
      max-height: 200px;
      margin-top: 16px;
    }

    /* CTA */
    .cta-section {
      background: linear-gradient(135deg, var(--brand-green), #06B878);
      text-align: center;
      padding: 100px 0;
      color: white;
      position: relative;
    }
    .cta-title {
      font-size: 42px;
      font-weight: 700;
    }
    .cta-buttons {
      display: flex;
      gap: 20px;
      justify-content: center;
      margin-top: 40px;
    }

    /* Footer */
    .footer {
      background: var(--deep-green);
      color: var(--light-gray);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer a {
      color: var(--light-gray);
      display: block;
      margin-bottom: 12px;
    }
    .copyright {
      margin-top: 40px;
      text-align: center;
      border-top: 1px solid rgba(255,255,255,0.1);
      padding-top: 24px;
    }

    @media (max-width: 1024px) {
      .hero-grid, .scene-row { grid-template-columns: 1fr; }
      .card-grid { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero-title { font-size: 36px; }
      .section-title { font-size: 28px; }
      .card-grid, .stats-grid, .footer-grid { grid-template-columns: 1fr; }
      .container { padding: 0 20px; }
    }