/* roulang page: index */
:root {
      --deep-blue: #0B1A2F;
      --dark-card: #1E293B;
      --electric-cyan: #00E5FF;
      --data-orange: #FF6B35;
      --success-green: #00C9A7;
      --light-bg: #F4F6F9;
      --white: #FFFFFF;
      --gray-100: #F8FAFC;
      --gray-200: #E2E8F0;
      --gray-400: #94A3B8;
      --gray-500: #64748B;
      --text-main: #1E293B;
      --text-secondary: #475569;
      --shadow-light: 0 4px 16px rgba(0,0,0,0.04);
      --shadow-glass: 0 8px 32px rgba(0,0,0,0.25);
      --shadow-lift: 0 12px 40px rgba(0,0,0,0.12);
      --radius-lg: 24px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --radius-full: 20px;
      --font-cn: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --font-num: 'Inter', system-ui, -apple-system, sans-serif;
    }

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

    body {
      font-family: var(--font-cn);
      background-color: var(--light-bg);
      color: var(--text-main);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      display: flex;
      min-height: 100vh;
    }

    h1, h2, h3, h4 {
      font-family: var(--font-cn);
      font-weight: 700;
      letter-spacing: -0.02em;
    }

    h2 {
      font-size: 2.25rem;
      line-height: 2.75rem;
      margin-bottom: 1rem;
    }

    h3 {
      font-size: 1.5rem;
      line-height: 2rem;
      font-weight: 600;
    }

    h4 {
      font-size: 1.25rem;
      line-height: 1.75rem;
      font-weight: 500;
    }

    .font-num {
      font-family: var(--font-num);
    }

    /* 左侧竖向导航 */
    .side-nav {
      width: 240px;
      height: 100vh;
      background: var(--deep-blue);
      position: fixed;
      left: 0;
      top: 0;
      display: flex;
      flex-direction: column;
      padding: 2rem 1.5rem;
      z-index: 50;
      box-shadow: 4px 0 20px rgba(0,0,0,0.15);
    }

    .nav-brand {
      margin-bottom: 3rem;
      display: flex;
      flex-direction: column;
    }

    .nav-brand .logo-text {
      font-size: 1.8rem;
      font-weight: 700;
      color: var(--white);
      letter-spacing: -0.5px;
      line-height: 1.2;
      border-bottom: 3px solid var(--electric-cyan);
      display: inline-block;
      padding-bottom: 0.25rem;
      width: fit-content;
    }

    .nav-links {
      list-style: none;
      flex: 1;
      display: flex;
      flex-direction: column;
      gap: 0.5rem;
    }

    .nav-links li a {
      display: flex;
      align-items: center;
      padding: 0.75rem 1rem;
      color: var(--gray-400);
      text-decoration: none;
      font-weight: 500;
      font-size: 0.95rem;
      border-radius: var(--radius-sm);
      position: relative;
      transition: all 0.2s ease;
    }

    .nav-links li a::before {
      content: '';
      position: absolute;
      left: 0;
      top: 10%;
      height: 80%;
      width: 4px;
      background: transparent;
      border-radius: 0 4px 4px 0;
      transition: background 0.2s;
    }

    .nav-links li a:hover {
      color: var(--electric-cyan);
      background: rgba(255,255,255,0.04);
    }

    .nav-links li a.active {
      color: var(--electric-cyan);
      background: rgba(0,229,255,0.08);
    }

    .nav-links li a.active::before {
      background: var(--electric-cyan);
      box-shadow: 0 0 12px var(--electric-cyan);
    }

    .nav-footer {
      margin-top: auto;
      color: var(--gray-500);
      font-size: 0.8rem;
    }

    /* 主内容区域 */
    .main-content {
      margin-left: 240px;
      flex: 1;
      width: calc(100% - 240px);
      max-width: 100%;
    }

    /* 组件样式 */
    .glass-card {
      background: rgba(255,255,255,0.05);
      backdrop-filter: blur(20px);
      border: 1px solid rgba(255,255,255,0.1);
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-glass);
    }

    .btn-glow {
      background: var(--electric-cyan);
      color: var(--deep-blue);
      font-weight: 700;
      padding: 0.85rem 2.2rem;
      border-radius: var(--radius-md);
      border: none;
      cursor: pointer;
      box-shadow: 0 0 20px rgba(0,229,255,0.5);
      transition: all 0.25s ease;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-size: 1rem;
    }

    .btn-glow:hover {
      box-shadow: 0 0 30px rgba(0,229,255,0.8);
      background: #33EAFF;
      transform: scale(1.03);
    }

    .btn-outline {
      background: transparent;
      border: 1px solid var(--electric-cyan);
      color: var(--electric-cyan);
      font-weight: 600;
      padding: 0.75rem 1.8rem;
      border-radius: var(--radius-md);
      transition: all 0.2s;
      display: inline-flex;
      align-items: center;
      gap: 0.5rem;
    }

    .btn-outline:hover {
      background: rgba(0,229,255,0.1);
    }

    .feature-card {
      background: white;
      border-radius: var(--radius-lg);
      padding: 2rem;
      box-shadow: var(--shadow-light);
      transition: all 0.3s ease;
      border-top: 3px solid transparent;
    }

    .feature-card:hover {
      transform: translateY(-8px);
      box-shadow: var(--shadow-lift);
      border-top-color: var(--electric-cyan);
    }

    .case-card {
      border-radius: var(--radius-lg);
      overflow: hidden;
      background: white;
      box-shadow: var(--shadow-light);
      transition: transform 0.25s;
      break-inside: avoid;
      margin-bottom: 1.5rem;
    }

    .case-card:hover .case-img {
      transform: scale(1.05);
    }

    .case-img {
      transition: transform 0.4s ease;
      width: 100%;
      height: auto;
      display: block;
      aspect-ratio: 4/3;
      object-fit: cover;
    }

    .faq-item {
      background: white;
      border-radius: var(--radius-md);
      margin-bottom: 0.75rem;
      box-shadow: var(--shadow-light);
      overflow: hidden;
    }

    .faq-question {
      padding: 1.25rem 1.5rem;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      background: white;
      border: none;
      width: 100%;
      text-align: left;
      font-size: 1.1rem;
    }

    .faq-answer {
      padding: 0 1.5rem 1.5rem;
      color: var(--text-secondary);
      display: none;
      background: var(--gray-100);
      margin: 0 1rem 1rem;
      border-radius: var(--radius-sm);
    }

    .faq-item.active .faq-answer {
      display: block;
    }

    .faq-item.active .faq-icon {
      transform: rotate(45deg);
      color: var(--electric-cyan);
    }

    .comparison-col.highlight {
      background: rgba(255,255,255,0.08);
      backdrop-filter: blur(16px);
      border: 1px solid rgba(255,255,255,0.15);
      border-radius: var(--radius-lg);
      transform: scale(1.02);
    }

    @media (max-width: 1024px) {
      .side-nav {
        width: 200px;
      }
      .main-content {
        margin-left: 200px;
        width: calc(100% - 200px);
      }
      h2 {
        font-size: 1.9rem;
      }
    }

    @media (max-width: 768px) {
      body {
        flex-direction: column;
      }
      .side-nav {
        position: relative;
        width: 100%;
        height: auto;
        flex-direction: row;
        align-items: center;
        justify-content: space-between;
        padding: 1rem 1.5rem;
        box-shadow: 0 2px 10px rgba(0,0,0,0.2);
      }
      .nav-links {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        width: 100%;
        background: var(--deep-blue);
        flex-direction: column;
        padding: 1rem;
        z-index: 100;
      }
      .nav-links.open {
        display: flex;
      }
      .main-content {
        margin-left: 0;
        width: 100%;
      }
      .mobile-menu-btn {
        display: block;
        color: white;
        font-size: 1.5rem;
      }
      h2 {
        font-size: 1.75rem;
        line-height: 2.2rem;
      }
      .glass-card {
        backdrop-filter: blur(12px);
      }
    }

    @media (min-width: 769px) {
      .mobile-menu-btn {
        display: none;
      }
    }