/* roulang page: index */
/* 全局变量与现代重置 */
    :root {
      --primary: #0A0E27;
      --accent: #00F0FF;
      --highlight: #FF3C00;
      --bg-light: #F5F7FC;
      --card-bg: rgba(255, 255, 255, 0.72);
      --card-border: rgba(255, 255, 255, 0.35);
      --text-primary: #0A0E27;
      --text-body: #2E3A4D;
      --text-muted: #6B7B8F;
      --white: #FFFFFF;
      --glass-bg: rgba(10, 14, 39, 0.75);
      --shadow-card: 0 8px 32px rgba(10, 14, 39, 0.08);
      --shadow-hover: 0 16px 48px rgba(10, 14, 39, 0.15);
      --radius-card: 18px;
      --radius-btn: 50px;
      --radius-lg: 22px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --font-number: "Inter", system-ui, -apple-system, sans-serif;
      --transition: 0.25s ease;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-body);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

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

    button, input, textarea {
      font-family: inherit;
    }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
      width: 100%;
    }

    /* 导航栏 - 玻璃拟态固定顶栏 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: var(--glass-bg);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(255, 255, 255, 0.1);
      z-index: 1000;
      display: flex;
      align-items: center;
      transition: background 0.3s;
    }

    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }

    .logo {
      font-size: 1.8rem;
      font-weight: 700;
      color: var(--accent);
      letter-spacing: -0.5px;
      display: flex;
      align-items: center;
      gap: 8px;
      white-space: nowrap;
    }
    .logo span {
      color: var(--white);
      font-weight: 400;
      font-size: 1.2rem;
    }

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

    .nav-menu a {
      color: rgba(255, 255, 255, 0.85);
      font-weight: 500;
      font-size: 1rem;
      position: relative;
      padding: 4px 0;
      transition: color 0.2s;
    }

    .nav-menu a:hover,
    .nav-menu a.active {
      color: var(--accent);
    }

    .nav-menu a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent);
      box-shadow: 0 0 8px var(--accent);
      transition: width 0.25s ease;
    }

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

    .menu-toggle {
      display: none;
      background: none;
      border: none;
      color: var(--white);
      font-size: 2rem;
      cursor: pointer;
      line-height: 1;
    }

    /* 移动端抽屉导航 */
    @media (max-width: 768px) {
      .nav-menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 70%;
        max-width: 320px;
        height: 100vh;
        background: rgba(10, 14, 39, 0.95);
        backdrop-filter: blur(24px);
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 40px;
        transition: right 0.3s ease;
        z-index: 999;
      }
      .nav-menu.open {
        right: 0;
      }
      .nav-menu a {
        font-size: 1.5rem;
        color: var(--white);
      }
      .menu-toggle {
        display: block;
        z-index: 1001;
      }
    }

    /* 首屏 Hero 双栏杂志风格 */
    .hero {
      min-height: 100vh;
      background: linear-gradient(135deg, #0A0E27 0%, #121836 100%);
      display: flex;
      align-items: center;
      position: relative;
      overflow: hidden;
      padding-top: 72px;
    }
    .hero::before {
      content: "";
      position: absolute;
      top: -20%;
      right: -10%;
      width: 500px;
      height: 500px;
      background: radial-gradient(circle, rgba(0,240,255,0.15) 0%, transparent 70%);
      border-radius: 50%;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1.2fr 0.9fr;
      gap: 48px;
      align-items: center;
      position: relative;
      z-index: 2;
    }
    .hero-left h1 {
      font-size: 3.5rem;
      font-weight: 700;
      line-height: 1.2;
      background: linear-gradient(to right, #00F0FF, #FFFFFF);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      margin-bottom: 1.5rem;
      letter-spacing: -0.5px;
    }
    .hero-sub {
      font-size: 1.2rem;
      color: rgba(255,255,255,0.7);
      margin-bottom: 2rem;
      max-width: 500px;
    }
    .hero-right {
      background: var(--card-bg);
      backdrop-filter: blur(18px);
      border: 1px solid var(--card-border);
      border-radius: 28px;
      padding: 2.5rem 2rem;
      text-align: center;
      box-shadow: 0 20px 40px rgba(0,0,0,0.3);
    }
    .trust-badge {
      color: var(--accent);
      font-weight: 600;
      margin-bottom: 1.5rem;
      font-size: 0.9rem;
      letter-spacing: 1px;
    }
    .btn {
      display: inline-block;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      transition: all 0.25s ease;
      cursor: pointer;
      border: none;
      font-size: 1rem;
      text-align: center;
    }
    .btn-primary-glow {
      background: var(--accent);
      color: var(--primary);
      box-shadow: 0 0 24px rgba(0,240,255,0.45);
    }
    .btn-primary-glow:hover {
      box-shadow: 0 0 40px rgba(0,240,255,0.7);
      background: #33f5ff;
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--accent);
      color: var(--accent);
      margin-left: 12px;
    }
    .btn-outline:hover {
      background: rgba(0,240,255,0.08);
    }

    @media (max-width: 1024px) {
      .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
      }
      .hero-left h1 {
        font-size: 2.8rem;
      }
      .hero-sub {
        margin-left: auto;
        margin-right: auto;
      }
    }
    @media (max-width: 520px) {
      .hero-left h1 {
        font-size: 2.2rem;
      }
    }

    /* 通用区块标题 */
    .section {
      padding: 80px 0;
    }
    .section-label {
      font-size: 0.8rem;
      font-weight: 500;
      letter-spacing: 2px;
      text-transform: uppercase;
      color: var(--accent);
      margin-bottom: 0.5rem;
    }
    h2 {
      font-size: 2.4rem;
      font-weight: 700;
      color: var(--text-primary);
      letter-spacing: -0.5px;
      margin-bottom: 2rem;
    }
    .text-center {
      text-align: center;
    }

    /* 亮点网格 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .feature-card {
      background: var(--card-bg);
      backdrop-filter: blur(18px);
      border: 1px solid var(--card-border);
      border-radius: var(--radius-card);
      padding: 2rem 1.5rem;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .feature-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
      border-color: var(--accent);
    }
    .feature-icon {
      font-size: 2.5rem;
      color: var(--accent);
      margin-bottom: 1rem;
    }
    .feature-title {
      font-size: 1.5rem;
      font-weight: 600;
      margin-bottom: 0.5rem;
    }

    @media (max-width: 1024px) {
      .features-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 640px) {
      .features-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 瀑布流产品卡片 */
    .waterfall-grid {
      columns: 3;
      column-gap: 24px;
      margin-top: 2rem;
    }
    .waterfall-item {
      break-inside: avoid;
      margin-bottom: 24px;
      background: var(--white);
      border-radius: 20px;
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .waterfall-item:hover {
      transform: translateY(-4px);
      box-shadow: 0 20px 40px rgba(0,240,255,0.2);
    }
    .waterfall-img {
      height: 180px;
      background-size: cover;
      background-position: center;
    }
    .waterfall-content {
      padding: 1.5rem;
    }
    @media (max-width: 1024px) {
      .waterfall-grid {
        columns: 2;
      }
    }
    @media (max-width: 640px) {
      .waterfall-grid {
        columns: 1;
      }
    }

    /* 方案对比双卡 */
    .compare-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 32px;
    }
    .compare-card {
      background: var(--white);
      border-radius: var(--radius-lg);
      padding: 2.5rem;
      box-shadow: var(--shadow-card);
    }
    .compare-left {
      border-left: 4px solid var(--accent);
    }
    .compare-right {
      border-left: 4px solid var(--highlight);
    }
    .compare-price {
      font-size: 2.5rem;
      font-weight: 700;
      color: var(--primary);
    }
    @media (max-width: 768px) {
      .compare-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 数据背书 */
    .stats-grid {
      display: flex;
      justify-content: space-around;
      flex-wrap: wrap;
      gap: 2rem;
      text-align: center;
    }
    .stat-number {
      font-size: 3rem;
      font-weight: 700;
      color: var(--accent);
      font-family: var(--font-number);
    }

    /* FAQ */
    .faq-item {
      background: rgba(255,255,255,0.6);
      border-radius: 12px;
      margin-bottom: 12px;
      padding: 1rem 1.5rem;
      cursor: pointer;
    }
    .faq-question {
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-muted);
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-top: 12px;
    }

    /* CTA 横幅 */
    .cta-band {
      background: var(--primary);
      border-radius: 32px;
      padding: 3rem 2rem;
      text-align: center;
      color: white;
      margin: 60px 0;
    }
    .btn-highlight {
      background: var(--highlight);
      color: white;
      box-shadow: 0 0 20px rgba(255,60,0,0.5);
    }

    /* 表单 */
    .contact-form input, .contact-form textarea {
      width: 100%;
      padding: 14px;
      border: 1px solid rgba(10,14,39,0.15);
      border-radius: 12px;
      margin-bottom: 16px;
      background: white;
    }

    /* 页脚 */
    .footer {
      background: #0A0E27;
      color: rgba(255,255,255,0.7);
      padding: 4rem 0 2rem;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    @media (max-width: 768px) {
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }