/* roulang page: index */
:root {
      --primary-red: #E53935;
      --primary-red-dark: #C62828;
      --deep-bg: #1B1B2F;
      --deep-bg-light: #16213E;
      --accent-yellow: #FFCA28;
      --white: #FFFFFF;
      --gray-bg: #F8F9FA;
      --card-white: #FFFFFF;
      --text-black: #1A1A1A;
      --text-gray: #5F6368;
      --border-gray: #E0E0E0;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-mono: "DIN Alternate", "Roboto Mono", monospace;
      --shadow-sm: 0 2px 12px rgba(0,0,0,0.06);
      --shadow-md: 0 8px 24px rgba(0,0,0,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-tag: 6px;
      --max-width: 1200px;
      --nav-height: 64px;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--white);
      color: var(--text-black);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

    h1, h2, h3, h4 {
      font-weight: 700;
      line-height: 1.3;
    }

    h1 {
      font-size: 48px;
      letter-spacing: -0.5px;
    }

    h2 {
      font-size: 36px;
      margin-bottom: 16px;
    }

    h3 {
      font-size: 22px;
      font-weight: 600;
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: var(--font-sans);
      font-weight: 600;
      border: none;
      outline: none;
      transition: all 0.25s ease;
    }

    .btn:focus-visible {
      outline: 2px solid var(--accent-yellow);
      outline-offset: 2px;
    }

    /* 导航栏 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      box-shadow: 0 1px 8px rgba(0,0,0,0.06);
      z-index: 1000;
      display: flex;
      align-items: center;
      transition: background 0.3s, box-shadow 0.3s;
    }

    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 20px;
    }

    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-size: 24px;
      font-weight: 700;
      color: var(--primary-red);
      text-decoration: none;
    }

    .logo-icon {
      width: 32px;
      height: 32px;
      background: var(--primary-red);
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 18px;
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }

    .nav-link {
      font-weight: 500;
      color: var(--text-black);
      position: relative;
      padding: 8px 0;
    }

    .nav-link.active {
      color: var(--primary-red);
    }

    .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 100%;
      height: 2px;
      background: var(--primary-red);
    }

    .btn-primary {
      background: var(--primary-red);
      color: white;
      border-radius: var(--radius-btn);
      padding: 12px 28px;
      font-size: 16px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      box-shadow: 0 4px 12px rgba(229,57,53,0.25);
    }

    .btn-primary:hover {
      background: var(--primary-red-dark);
      box-shadow: 0 6px 16px rgba(229,57,53,0.35);
      transform: translateY(-1px);
    }

    .btn-secondary {
      background: transparent;
      color: var(--primary-red);
      border: 1.5px solid var(--primary-red);
      border-radius: var(--radius-btn);
      padding: 10px 26px;
      font-size: 16px;
    }

    .btn-secondary:hover {
      background: rgba(229,57,53,0.08);
    }

    .btn-light {
      background: white;
      color: var(--primary-red);
      border-radius: var(--radius-btn);
      padding: 14px 32px;
      font-weight: 700;
    }

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

    .hamburger span {
      width: 26px;
      height: 2.5px;
      background: var(--text-black);
      border-radius: 2px;
      transition: 0.3s;
    }

    /* Hero */
    .hero {
      background: linear-gradient(135deg, #1B1B2F 0%, #16213E 100%);
      min-height: 85vh;
      display: flex;
      align-items: center;
      padding-top: var(--nav-height);
      position: relative;
      overflow: hidden;
    }

    .hero::before {
      content: '';
      position: absolute;
      top: -20%;
      right: -10%;
      width: 70%;
      height: 120%;
      background: radial-gradient(circle at 30% 50%, rgba(229,57,53,0.15) 0%, transparent 60%);
      pointer-events: none;
    }

    .hero-content {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 60px;
      position: relative;
      z-index: 2;
    }

    .hero-text {
      flex: 1;
      color: white;
    }

    .hero-text h1 {
      color: white;
      margin-bottom: 20px;
      font-size: 52px;
    }

    .hero-highlight {
      color: var(--accent-yellow);
    }

    .hero-sub {
      font-size: 18px;
      color: rgba(255,255,255,0.8);
      margin-bottom: 32px;
      line-height: 1.6;
    }

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

    .hero-image {
      flex: 1;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: 20px;
      min-height: 380px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.5);
      border: 1px solid rgba(255,255,255,0.1);
    }

    section {
      padding: 80px 0;
    }

    .section-header {
      text-align: center;
      margin-bottom: 48px;
    }

    .section-header h2 {
      color: var(--text-black);
    }

    .section-desc {
      color: var(--text-gray);
      font-size: 18px;
    }

    /* 核心优势 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 32px;
    }

    .feature-card {
      background: var(--card-white);
      padding: 32px 24px;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      text-align: center;
      transition: all 0.3s;
    }

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

    .feature-icon {
      width: 64px;
      height: 64px;
      background: var(--primary-red);
      border-radius: 50%;
      margin: 0 auto 20px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 28px;
    }

    .feature-card h3 {
      margin-bottom: 12px;
    }

    /* 功能分组 */
    .solutions-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 32px;
    }

    .solution-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--shadow-sm);
      display: flex;
      gap: 20px;
      border-left: 6px solid var(--primary-red);
      transition: 0.3s;
    }

    .solution-card:hover {
      box-shadow: var(--shadow-md);
    }

    .solution-icon {
      font-size: 32px;
      color: var(--primary-red);
      min-width: 48px;
    }

    /* 使用场景 */
    .scenario-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }

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

    .scenario-img {
      flex: 1;
      border-radius: 16px;
      overflow: hidden;
      box-shadow: var(--shadow-md);
    }

    .scenario-text {
      flex: 1;
    }

    .tag {
      background: var(--primary-red);
      color: white;
      padding: 4px 14px;
      border-radius: 20px;
      font-size: 13px;
      font-weight: 600;
      display: inline-block;
      margin-bottom: 12px;
    }

    /* 案例数据 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      margin-bottom: 48px;
    }

    .stat-item {
      background: white;
      padding: 28px;
      border-radius: var(--radius-card);
      text-align: center;
      box-shadow: var(--shadow-sm);
    }

    .stat-number {
      font-family: var(--font-mono);
      font-size: 42px;
      font-weight: 700;
      color: var(--primary-red);
    }

    .logo-wall {
      display: flex;
      justify-content: center;
      gap: 40px;
      flex-wrap: wrap;
      filter: grayscale(1);
      opacity: 0.7;
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }

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

    .faq-question {
      width: 100%;
      background: transparent;
      border: none;
      padding: 20px 0;
      font-size: 18px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--text-black);
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-gray);
      padding-left: 16px;
    }

    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 16px;
    }

    /* CTA */
    .cta-section {
      background: var(--primary-red);
      text-align: center;
      padding: 80px 20px;
    }

    .cta-section h2 {
      color: white;
    }

    /* 页脚 */
    .footer {
      background: var(--deep-bg);
      color: #ccc;
      padding: 60px 0 20px;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      margin-bottom: 40px;
    }

    @media (max-width: 1024px) {
      .features-grid { grid-template-columns: repeat(2,1fr); }
      .solutions-grid { grid-template-columns: 1fr; }
    }

    @media (max-width: 768px) {
      h1 { font-size: 36px; }
      .hero-content { flex-direction: column; }
      .hero-image { min-height: 250px; width: 100%; }
      .nav-menu { display: none; }
      .hamburger { display: flex; }
      .features-grid, .stats-grid { grid-template-columns: 1fr; }
      .scenario-row { flex-direction: column; }
      .footer-grid { grid-template-columns: 1fr; }
    }