/* roulang page: index */
:root {
      --primary: #FF4D00;
      --primary-dark: #1A0000;
      --accent: #00E5FF;
      --gold: #FFB800;
      --bg-deep: #0A0A0A;
      --bg-card: #141414;
      --bg-glass: rgba(20, 20, 20, 0.8);
      --text-white: #FFFFFF;
      --text-gray: #B0B0B0;
      --text-muted: #666666;
      --border-light: rgba(255, 255, 255, 0.05);
      --border-accent: rgba(0, 229, 255, 0.3);
      --shadow-glow: 0 0 20px rgba(255, 77, 0, 0.6);
      --shadow-cyan: 0 20px 40px rgba(0, 229, 255, 0.15);
      --radius-sm: 4px;
      --radius-md: 8px;
      --radius-lg: 16px;
      --space-xs: 8px;
      --space-sm: 16px;
      --space-md: 24px;
      --space-lg: 48px;
      --space-xl: 64px;
      --space-2xl: 120px;
      --sidebar-width: 90px;
      --font-family: 'Inter', 'SF Pro Text', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
      background-color: var(--bg-deep);
    }
    body {
      font-family: var(--font-family);
      background-color: var(--bg-deep);
      color: var(--text-gray);
      line-height: 1.7;
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
      display: flex;
      min-height: 100vh;
      overflow-x: hidden;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }
    button, input, textarea {
      font-family: inherit;
    }
    /* 左侧竖向导航 */
    .sidebar {
      position: fixed;
      left: 0;
      top: 0;
      width: var(--sidebar-width);
      height: 100vh;
      background: rgba(10, 10, 10, 0.9);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-right: 1px solid var(--border-light);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      z-index: 100;
      padding: var(--space-md) 0;
    }
    .logo {
      writing-mode: vertical-rl;
      text-orientation: mixed;
      font-weight: 900;
      font-size: 1.6rem;
      letter-spacing: 0.2em;
      color: var(--text-white);
      margin-bottom: auto;
      text-transform: uppercase;
      background: linear-gradient(180deg, var(--primary) 0%, var(--accent) 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      cursor: pointer;
      transition: opacity 0.2s;
    }
    .logo:hover {
      opacity: 0.8;
    }
    .nav-menu {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 28px;
      list-style: none;
      writing-mode: vertical-rl;
      text-orientation: mixed;
      margin: auto 0;
    }
    .nav-item {
      color: #888;
      font-weight: 600;
      font-size: 0.9rem;
      letter-spacing: 0.15em;
      text-transform: uppercase;
      cursor: pointer;
      transition: color 0.25s;
      position: relative;
      padding: 4px 0;
    }
    .nav-item::before {
      content: '';
      position: absolute;
      left: -12px;
      top: 0;
      height: 100%;
      width: 3px;
      background: var(--primary);
      transform: scaleY(0);
      transition: transform 0.2s ease;
    }
    .nav-item:hover,
    .nav-item.active {
      color: var(--accent);
    }
    .nav-item:hover::before,
    .nav-item.active::before {
      transform: scaleY(1);
    }
    .sidebar-footer {
      margin-top: auto;
      writing-mode: vertical-rl;
      text-orientation: mixed;
      color: #555;
      font-size: 0.7rem;
      letter-spacing: 0.1em;
    }
    /* 主内容区 */
    .main-content {
      margin-left: var(--sidebar-width);
      width: calc(100% - var(--sidebar-width));
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 var(--space-md);
    }
    section {
      padding: var(--space-2xl) 0;
    }
    /* 排版 */
    h1, h2, h3, .h1, .h2, .h3 {
      color: var(--text-white);
      font-weight: 700;
    }
    h1 {
      font-weight: 900;
      font-size: clamp(3rem, 8vw, 5.5rem);
      letter-spacing: -0.02em;
      text-transform: uppercase;
      line-height: 1.05;
      margin-bottom: var(--space-sm);
    }
    .h1-sub {
      color: var(--accent);
      font-size: 1.4rem;
      letter-spacing: 0.2em;
      font-weight: 600;
      margin-bottom: var(--space-md);
    }
    h2 {
      font-size: clamp(2rem, 5vw, 3rem);
      letter-spacing: 0.05em;
      margin-bottom: var(--space-lg);
      display: flex;
      align-items: center;
      gap: var(--space-sm);
    }
    h2 span {
      color: var(--accent);
      font-weight: 400;
    }
    .section-desc {
      color: var(--text-gray);
      max-width: 700px;
      margin-bottom: var(--space-xl);
      font-size: 1.1rem;
    }
    /* 按钮 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      letter-spacing: 0.1em;
      text-transform: uppercase;
      padding: 14px 32px;
      border: none;
      cursor: pointer;
      clip-path: polygon(10% 0%, 100% 0%, 90% 100%, 0% 100%);
      transition: all 0.25s ease;
      background: transparent;
      color: white;
      font-size: 0.9rem;
      gap: 8px;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
    }
    .btn-primary:hover {
      background: #FF6B33;
      box-shadow: var(--shadow-glow);
    }
    .btn-outline {
      border: 2px solid var(--accent);
      color: var(--accent);
      background: transparent;
    }
    .btn-outline:hover {
      background: var(--accent);
      color: #0A0A0A;
    }
    .btn-group {
      display: flex;
      gap: var(--space-sm);
      flex-wrap: wrap;
      margin-top: var(--space-md);
    }
    /* 卡片 */
    .card {
      background: var(--bg-card);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      transition: transform 0.25s, box-shadow 0.3s, border-color 0.2s;
    }
    .card:hover {
      transform: translateY(-5px);
      border-color: var(--accent);
      box-shadow: var(--shadow-cyan);
    }
    /* 汉堡菜单 (移动端) */
    .mobile-header {
      display: none;
    }
    /* 表单 */
    .input-field {
      background: #1A1A1A;
      border: none;
      border-bottom: 2px solid #333;
      padding: 14px 12px;
      color: white;
      width: 100%;
      font-size: 1rem;
      transition: border 0.2s;
      outline: none;
      border-radius: 0;
    }
    .input-field:focus {
      border-bottom-color: var(--accent);
      box-shadow: 0 4px 10px rgba(0, 229, 255, 0.2);
    }
    .input-field::placeholder {
      color: #666;
    }
    /* 网格与布局 */
    .grid-2 {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: var(--space-lg);
    }
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: var(--space-lg);
    }
    .asymmetric-grid {
      display: grid;
      grid-template-columns: 1.5fr 1fr 1fr;
      gap: var(--space-md);
    }
    .masonry {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: var(--space-md);
    }
    .masonry-item {
      grid-row: span var(--rows, 1);
    }
    /* Hero */
    .hero {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: var(--space-xl);
      align-items: center;
      min-height: 90vh;
      padding-top: var(--space-2xl);
    }
    .hero-visual {
      position: relative;
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      min-height: 500px;
      border-radius: var(--radius-lg);
      box-shadow: 0 0 40px rgba(0, 229, 255, 0.2);
      display: flex;
      align-items: flex-end;
      overflow: hidden;
    }
    .hero-visual::after {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(0deg, rgba(10,10,10,0.7) 0%, transparent 60%);
    }
    /* 对比表格风格 */
    .compare-table {
      display: grid;
      grid-template-columns: 1fr 1fr 1fr;
      gap: 2px;
      background: #1f1f1f;
      border-radius: var(--radius-md);
      overflow: hidden;
    }
    .compare-cell {
      background: var(--bg-card);
      padding: var(--space-lg);
    }
    .compare-cell.highlight {
      background: #1A1A1A;
      border-left: 3px solid var(--primary);
    }
    /* 数据荣誉 */
    .stat-number {
      font-size: 3.5rem;
      font-weight: 900;
      color: var(--gold);
      line-height: 1;
    }
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: var(--space-md) 0;
      cursor: pointer;
    }
    .faq-question {
      font-weight: 700;
      color: white;
      font-size: 1.2rem;
      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-gray);
      padding-right: 20px;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      margin-top: var(--space-sm);
    }
    /* 页脚 */
    .footer {
      border-top: 1px solid var(--border-light);
      padding: var(--space-lg) 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      color: #666;
    }
    /* 响应式 */
    @media (max-width: 1024px) {
      :root {
        --sidebar-width: 0px;
      }
      .sidebar {
        display: none;
      }
      .main-content {
        margin-left: 0;
        width: 100%;
      }
      .mobile-header {
        display: flex;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        background: #0A0A0A;
        padding: 16px 24px;
        justify-content: space-between;
        align-items: center;
        z-index: 200;
        border-bottom: 1px solid var(--border-light);
      }
      .mobile-logo {
        font-weight: 900;
        font-size: 1.4rem;
        color: var(--primary);
      }
      .hamburger {
        display: flex;
        flex-direction: column;
        gap: 5px;
        cursor: pointer;
      }
      .hamburger span {
        width: 25px;
        height: 3px;
        background: white;
        transition: 0.3s;
      }
      .mobile-menu {
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: rgba(10,10,10,0.98);
        backdrop-filter: blur(20px);
        display: flex;
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 40px;
        z-index: 150;
        transform: translateX(100%);
        transition: transform 0.3s ease;
      }
      .mobile-menu.open {
        transform: translateX(0);
      }
      .mobile-menu a {
        font-size: 2rem;
        font-weight: 700;
        color: white;
      }
      .hero {
        grid-template-columns: 1fr;
        padding-top: 100px;
      }
      .grid-2, .grid-3, .asymmetric-grid, .masonry {
        grid-template-columns: 1fr;
      }
      .compare-table {
        grid-template-columns: 1fr;
      }
    }