/* roulang page: index */
/* ----- 设计变量 ----- */
    :root {
      --bg-deep: #0A0E27;
      --bg-panel: #0F1535;
      --blue-electric: #00C2FF;
      --blue-glow: rgba(0, 194, 255, 0.25);
      --orange-energy: #FF6B35;
      --orange-light: #FF8C42;
      --text-primary: #F0F4FF;
      --text-secondary: #B0C0E0;
      --text-muted: #7B89A8;
      --glass-bg: rgba(10, 20, 50, 0.7);
      --glass-border: rgba(255, 255, 255, 0.08);
      --radius-card: 20px;
      --radius-button: 30px;
      --shadow-card: 0 10px 32px rgba(0, 0, 0, 0.5);
      --shadow-glow: 0 0 24px rgba(0, 194, 255, 0.35);
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --font-mono: 'DIN Alternate', 'Roboto Mono', 'Courier New', monospace;
      --max-width: 1200px;
      --nav-height: 72px;
      --transition-smooth: 0.25s cubic-bezier(0.2, 0.0, 0.1, 1);
    }

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

    html {
      scroll-behavior: smooth;
      background-color: var(--bg-deep);
    }

    body {
      font-family: var(--font-sans);
      background: var(--bg-deep);
      color: var(--text-primary);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }

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

    a {
      text-decoration: none;
      color: inherit;
    }

    button, input, select {
      font-family: inherit;
      outline: none;
    }

    /* 容器 */
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
      width: 100%;
    }

    /* ----- 导航 (沉浸式玻璃) ----- */
    .nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: rgba(10, 14, 39, 0.88);
      backdrop-filter: blur(16px);
      -webkit-backdrop-filter: blur(16px);
      z-index: 1000;
      border-bottom: 1px solid rgba(255, 255, 255, 0.06);
      display: flex;
      align-items: center;
      transition: var(--transition-smooth);
    }

    .nav .container {
      display: flex;
      align-items: center;
      justify-content: space-between;
    }

    .logo {
      font-weight: 800;
      font-size: 1.8rem;
      letter-spacing: 1px;
      color: white;
      display: flex;
      align-items: center;
      gap: 6px;
      background: linear-gradient(135deg, #ffffff 0%, #a0d0ff 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }

    .logo span {
      font-weight: 700;
      color: var(--blue-electric);
      -webkit-text-fill-color: var(--blue-electric);
    }

    .nav-links {
      display: flex;
      gap: 2.2rem;
      align-items: center;
      font-weight: 500;
      font-size: 0.95rem;
      color: var(--text-secondary);
    }

    .nav-links a {
      transition: color 0.2s, text-shadow 0.2s;
      position: relative;
      padding: 4px 0;
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--blue-electric);
      box-shadow: 0 0 10px var(--blue-electric);
      transition: width 0.25s ease;
    }

    .nav-links a:hover {
      color: white;
      text-shadow: 0 0 8px rgba(0,194,255,0.5);
    }

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

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
      border: none;
      padding: 8px;
    }

    .hamburger span {
      display: block;
      width: 26px;
      height: 2.5px;
      background: white;
      border-radius: 2px;
      transition: 0.2s;
    }

    /* 移动端导航 */
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: var(--nav-height);
        left: 0;
        width: 100%;
        background: rgba(8, 12, 32, 0.96);
        backdrop-filter: blur(20px);
        flex-direction: column;
        padding: 28px 24px;
        gap: 24px;
        display: none;
        border-bottom: 1px solid rgba(0,194,255,0.2);
      }
      .nav-links.active {
        display: flex;
      }
      .hamburger {
        display: flex;
      }
      .logo {
        font-size: 1.6rem;
      }
    }

    /* ----- 首屏 Hero ----- */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: radial-gradient(circle at 20% 30%, #13204a 0%, #0A0E27 85%);
      position: relative;
      overflow: hidden;
      padding-top: var(--nav-height);
    }

    .hero::before {
      content: "";
      position: absolute;
      inset: 0;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      opacity: 0.2;
      pointer-events: none;
    }

    .hero-grid {
      display: flex;
      align-items: center;
      gap: 3rem;
      position: relative;
      z-index: 2;
    }

    .hero-content {
      flex: 1;
    }

    .hero h1 {
      font-size: clamp(2.6rem, 6vw, 3.8rem);
      font-weight: 800;
      line-height: 1.2;
      margin-bottom: 1.5rem;
      background: linear-gradient(to right, #ffffff, #b0e0ff);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }

    .hero-sub {
      font-size: 1.2rem;
      color: var(--text-secondary);
      margin-bottom: 2.5rem;
      max-width: 550px;
    }

    .btn-group {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }

    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 34px;
      border-radius: var(--radius-button);
      font-weight: 600;
      font-size: 1rem;
      transition: all 0.3s ease;
      cursor: pointer;
      border: none;
      letter-spacing: 0.4px;
    }

    .btn-primary {
      background: linear-gradient(135deg, var(--orange-energy), var(--orange-light));
      color: white;
      box-shadow: 0 8px 22px rgba(255, 107, 53, 0.4);
    }

    .btn-primary:hover {
      box-shadow: 0 0 28px rgba(255, 107, 53, 0.7);
      transform: translateY(-2px);
    }

    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--blue-electric);
      color: var(--blue-electric);
      box-shadow: 0 0 10px rgba(0,194,255,0.15);
    }

    .btn-outline:hover {
      background: rgba(0, 194, 255, 0.08);
      box-shadow: 0 0 20px rgba(0,194,255,0.5);
      color: white;
    }

    .hero-visual {
      flex: 1;
      display: flex;
      justify-content: center;
      align-items: center;
    }

    .hero-dashboard {
      background: var(--glass-bg);
      backdrop-filter: blur(24px);
      border: 1px solid var(--glass-border);
      border-radius: 28px;
      padding: 20px;
      box-shadow: var(--shadow-card);
    }

    .hero-dashboard img {
      border-radius: 16px;
      width: 100%;
      max-width: 460px;
    }

    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
        text-align: center;
      }
      .hero-sub {
        margin-left: auto;
        margin-right: auto;
      }
      .btn-group {
        justify-content: center;
      }
    }

    /* 板块通用 */
    section {
      padding: 90px 0;
      position: relative;
    }

    .section-title {
      font-size: clamp(2rem, 5vw, 2.6rem);
      font-weight: 700;
      margin-bottom: 16px;
      color: white;
    }

    .section-sub {
      color: var(--text-secondary);
      font-size: 1.1rem;
      margin-bottom: 48px;
    }

    /* 指标看板 */
    .dashboard-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }

    .stat-card {
      background: var(--glass-bg);
      backdrop-filter: blur(18px);
      border: 1px solid var(--glass-border);
      border-radius: var(--radius-card);
      padding: 28px 20px;
      text-align: center;
      transition: all 0.3s;
    }

    .stat-card:hover {
      border-color: var(--blue-electric);
      box-shadow: var(--shadow-glow);
    }

    .stat-number {
      font-family: var(--font-mono);
      font-size: 2.8rem;
      font-weight: 700;
      color: var(--blue-electric);
      text-shadow: 0 0 12px rgba(0,194,255,0.6);
    }

    @media (max-width: 768px) {
      .dashboard-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }

    /* 服务矩阵 非对称 */
    .services-grid {
      display: grid;
      grid-template-columns: 1.4fr 1fr;
      gap: 24px;
    }

    .service-card {
      background: var(--glass-bg);
      backdrop-filter: blur(18px);
      border: 1px solid var(--glass-border);
      border-radius: var(--radius-card);
      padding: 28px;
      transition: 0.3s;
    }

    .service-card:hover {
      border-color: var(--blue-electric);
      box-shadow: var(--shadow-glow);
    }

    .service-card img {
      border-radius: 14px;
      margin-bottom: 20px;
      width: 100%;
      height: auto;
    }

    .right-stack {
      display: flex;
      flex-direction: column;
      gap: 24px;
    }

    @media (max-width: 768px) {
      .services-grid {
        grid-template-columns: 1fr;
      }
    }

    /* 对比区块 */
    .compare-wrapper {
      display: flex;
      gap: 2rem;
      align-items: center;
      flex-wrap: wrap;
      background: rgba(15, 21, 53, 0.5);
      border-radius: 28px;
      padding: 32px;
    }

    .compare-col {
      flex: 1;
    }

    .compare-col h3 {
      font-weight: 600;
      margin-bottom: 20px;
    }

    .metric {
      margin-bottom: 20px;
    }

    .progress {
      height: 8px;
      background: rgba(255,255,255,0.1);
      border-radius: 10px;
      margin-top: 6px;
      overflow: hidden;
    }

    .progress-fill {
      height: 100%;
      width: 0%;
      background: var(--blue-electric);
      border-radius: 10px;
    }

    @media (max-width: 768px) {
      .compare-wrapper {
        flex-direction: column;
      }
    }

    /* FAQ */
    .faq-item {
      background: var(--glass-bg);
      backdrop-filter: blur(16px);
      border: 1px solid var(--glass-border);
      border-radius: 16px;
      margin-bottom: 16px;
      transition: 0.2s;
    }

    .faq-question {
      padding: 18px 24px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      padding: 0 24px;
      color: var(--text-secondary);
      transition: max-height 0.35s ease;
    }

    .faq-item.active {
      border-color: var(--blue-electric);
    }

    .faq-item.active .faq-answer {
      max-height: 120px;
      padding-bottom: 20px;
    }

    /* 表单 */
    .contact-form {
      max-width: 600px;
      margin: 0 auto;
      background: var(--glass-bg);
      backdrop-filter: blur(20px);
      padding: 36px;
      border-radius: 28px;
      border: 1px solid var(--glass-border);
    }

    .input-field {
      width: 100%;
      padding: 14px 18px;
      margin-bottom: 20px;
      background: rgba(255,255,255,0.05);
      border: 1px solid rgba(255,255,255,0.1);
      border-radius: 14px;
      color: white;
    }

    .input-field:focus {
      border-color: var(--blue-electric);
      box-shadow: 0 0 12px rgba(0,194,255,0.4);
    }

    footer {
      background: #060B1F;
      padding: 48px 0 24px;
      color: var(--text-muted);
    }