/* roulang page: index */
/* ----- 设计变量与重置 ----- */
    :root {
      --primary: #0A0E27;
      --accent-cyan: #00F0FF;
      --accent-red: #FF3D00;
      --bg-deep: #060918;
      --card-bg: rgba(255, 255, 255, 0.03);
      --card-border: rgba(0, 240, 255, 0.15);
      --text-main: #E0E6F0;
      --text-muted: #8892B0;
      --glass-blur: blur(12px);
      --radius-lg: 16px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --shadow-glow: 0 0 20px rgba(0, 240, 255, 0.4), 0 0 60px rgba(0, 240, 255, 0.1);
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", "Inter", system-ui, -apple-system, sans-serif;
      --container-max: 1200px;
      --section-gap: 120px;
    }

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

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

    body {
      background-color: var(--bg-deep);
      color: var(--text-main);
      font-family: var(--font-sans);
      line-height: 1.8;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }

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

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

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

    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border-radius: var(--radius-md);
      padding: 14px 36px;
      font-weight: 600;
      font-size: 1rem;
      cursor: pointer;
      transition: all 0.25s ease;
      border: none;
      background: transparent;
      color: white;
      letter-spacing: 0.5px;
      line-height: 1.2;
      white-space: nowrap;
    }

    .btn-primary {
      background: linear-gradient(135deg, #00F0FF 0%, #0088FF 100%);
      color: #fff;
      box-shadow: 0 4px 20px rgba(0, 240, 255, 0.3);
    }

    .btn-primary:hover {
      transform: translateY(-2px);
      box-shadow: 0 8px 30px rgba(0, 240, 255, 0.6);
    }

    .btn-outline {
      border: 1.5px solid var(--accent-cyan);
      color: var(--accent-cyan);
      background: transparent;
    }

    .btn-outline:hover {
      background: rgba(0, 240, 255, 0.08);
      box-shadow: 0 0 18px rgba(0, 240, 255, 0.3);
      transform: translateY(-2px);
    }

    .btn-ghost {
      border: 1.5px solid rgba(255, 255, 255, 0.5);
      color: white;
    }

    .btn-ghost:hover {
      background: rgba(255, 255, 255, 0.1);
      border-color: white;
    }

    /* 导航 */
    .nav-bar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: rgba(6, 9, 24, 0.8);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(0, 240, 255, 0.15);
      transition: background 0.3s;
    }

    .nav-bar.scrolled {
      background: rgba(6, 9, 24, 0.96);
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
      height: 72px;
    }

    .logo {
      font-size: 1.8rem;
      font-weight: 800;
      letter-spacing: -0.5px;
      color: white;
      text-shadow: 0 0 12px var(--accent-cyan);
      display: flex;
      align-items: center;
      gap: 4px;
    }
    .logo span {
      color: var(--accent-cyan);
    }

    .nav-links {
      display: flex;
      gap: 2rem;
      align-items: center;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text-muted);
      font-size: 0.95rem;
      position: relative;
      padding: 6px 0;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--accent-cyan);
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent-cyan);
      transition: width 0.2s;
    }
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: none;
      border: none;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: white;
      transition: 0.3s;
    }

    .mobile-menu {
      display: none;
      position: fixed;
      top: 72px;
      left: 0;
      width: 100%;
      height: calc(100vh - 72px);
      background: rgba(4, 6, 18, 0.96);
      backdrop-filter: blur(30px);
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 2.2rem;
      font-size: 1.6rem;
      z-index: 999;
    }
    .mobile-menu.open {
      display: flex;
    }

    /* 区块间距 */
    section {
      padding: var(--section-gap) 0;
    }

    /* 首屏 Hero */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: radial-gradient(circle at 30% 40%, #0f1830 0%, #060918 80%);
      position: relative;
      overflow: hidden;
    }
    .hero::before {
      content: '';
      position: absolute;
      width: 100%;
      height: 100%;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      opacity: 0.25;
      z-index: 0;
    }
    .hero .container {
      position: relative;
      z-index: 2;
      display: flex;
      align-items: center;
      gap: 3rem;
    }
    .hero-text {
      flex: 1;
    }
    .hero-text h1 {
      font-size: clamp(2.5rem, 5vw, 3.5rem);
      font-weight: 800;
      line-height: 1.15;
      letter-spacing: -0.02em;
      margin-bottom: 1.5rem;
    }
    .hero-text .highlight {
      color: var(--accent-cyan);
      text-shadow: 0 0 18px rgba(0,240,255,0.5);
    }
    .hero-sub {
      color: var(--text-muted);
      font-size: 1.2rem;
      margin-bottom: 2.5rem;
      max-width: 500px;
    }
    .hero-buttons {
      display: flex;
      gap: 1rem;
      flex-wrap: wrap;
    }
    .hero-image {
      flex: 1;
      display: flex;
      justify-content: center;
    }
    .hero-image img {
      max-height: 420px;
      border-radius: 24px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.6);
      border: 1px solid rgba(0,240,255,0.2);
    }

    /* 核心优势 1+2 布局 */
    .advantages-grid {
      display: grid;
      grid-template-columns: 5fr 7fr;
      gap: 24px;
      align-items: start;
    }
    .adv-card {
      background: var(--card-bg);
      backdrop-filter: var(--glass-blur);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-lg);
      padding: 32px;
      transition: 0.25s;
    }
    .adv-card:hover {
      border-color: var(--accent-cyan);
      box-shadow: 0 12px 32px rgba(0,240,255,0.1);
    }
    .adv-main {
      grid-row: span 2;
      display: flex;
      flex-direction: column;
      gap: 20px;
    }
    .adv-icon {
      font-size: 2.4rem;
      color: var(--accent-cyan);
      filter: drop-shadow(0 0 8px #00f0ff);
    }
    .adv-title {
      font-size: 1.6rem;
      font-weight: 700;
    }
    .adv-desc {
      color: var(--text-muted);
    }

    /* 产品功能交错 */
    .feature-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }
    .feature-row.reverse {
      flex-direction: row-reverse;
    }
    .feature-text {
      flex: 1;
    }
    .feature-text h2 {
      font-size: 2.2rem;
      margin-bottom: 1.5rem;
    }
    .feature-list {
      list-style: none;
      margin-top: 1.5rem;
    }
    .feature-list li {
      display: flex;
      gap: 12px;
      margin-bottom: 1rem;
      color: var(--text-muted);
    }
    .feature-list li::before {
      content: "▹";
      color: var(--accent-cyan);
      font-weight: bold;
    }
    .feature-image img {
      border-radius: 20px;
      border: 1px solid rgba(0,240,255,0.25);
    }

    /* 场景卡片 */
    .scenario-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
      margin-top: 40px;
    }
    .scenario-card {
      background: var(--card-bg);
      backdrop-filter: var(--glass-blur);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-lg);
      overflow: hidden;
      transition: 0.3s;
    }
    .scenario-card:hover {
      transform: translateY(-8px);
      border-color: var(--accent-cyan);
      box-shadow: 0 16px 35px rgba(0,240,255,0.12);
    }
    .scenario-img {
      height: 180px;
      background-size: cover;
      background-position: center;
    }
    .scenario-content {
      padding: 24px;
    }

    /* 数据墙 */
    .stats-wall {
      display: flex;
      justify-content: space-around;
      flex-wrap: wrap;
      gap: 2rem;
      background: rgba(0,240,255,0.02);
      border-radius: 24px;
      padding: 48px 16px;
      backdrop-filter: blur(8px);
    }
    .stat-item {
      text-align: center;
    }
    .stat-number {
      font-size: 3rem;
      font-weight: 800;
      background: linear-gradient(to right, #00F0FF, #0088FF);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    /* FAQ */
    .faq-item {
      border-bottom: 1px solid rgba(0,240,255,0.1);
      padding: 24px 0;
    }
    .faq-question {
      font-weight: 700;
      font-size: 1.2rem;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease;
      color: var(--text-muted);
      margin-top: 0;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      margin-top: 16px;
    }

    /* 最终CTA */
    .cta-section {
      background: linear-gradient(135deg, #0A0E27 0%, #001F3F 100%);
      text-align: center;
      border-radius: 32px;
      padding: 80px 24px;
      margin: 0 24px;
      position: relative;
      overflow: hidden;
    }
    .cta-section::after {
      content: '';
      position: absolute;
      width: 200px;
      height: 200px;
      background: radial-gradient(circle, rgba(0,240,255,0.3) 0%, transparent 70%);
      top: -50px;
      right: -50px;
    }

    /* 页脚 */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 40px;
      padding: 60px 0 40px;
    }
    .copyright {
      border-top: 1px solid rgba(255,255,255,0.08);
      padding: 24px 0;
      text-align: center;
      color: var(--text-muted);
      font-size: 0.9rem;
    }

    @media (max-width: 1024px) {
      .advantages-grid { grid-template-columns: 1fr; }
      .feature-row { flex-direction: column; }
      .scenario-grid { grid-template-columns: 1fr 1fr; }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero .container { flex-direction: column; }
      .scenario-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .stats-wall { flex-direction: column; align-items: center; }
      section { padding: 80px 0; }
    }