/* roulang page: index */
/* 基础重置与变量 */
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    :root {
      --primary-obsidian: #1A1A1A;
      --accent-amethyst: #7B2FBE;
      --accent-blaze: #F05423;
      --accent: var(--accent-amethyst);
      --surface-warm: #FAFAFA;
      --surface-light: #F0F0F0;
      --text-primary: #111111;
      --text-body: #333333;
      --text-muted: #6B6B6B;
      --border-default: #EAEAEA;
      --radius-md: 12px;
      --radius-sm: 8px;
      --shadow-card: 0 4px 12px rgba(0,0,0,0.04);
      --shadow-hover: 0 8px 24px rgba(0,0,0,0.08);
      --transition-smooth: 0.25s ease-out;
      --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--surface-warm);
      color: var(--text-body);
      line-height: 1.4;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    button, input, textarea {
      font-family: inherit;
    }
    .container {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 20px;
      padding-right: 20px;
    }
    /* 导航 */
    .nav-bar {
      position: sticky;
      top: 0;
      z-index: 50;
      background: rgba(255,255,255,0.9);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(0,0,0,0.05);
      box-shadow: 0 1px 4px rgba(0,0,0,0.02);
      width: 100%;
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 16px 20px;
      max-width: 1280px;
      margin: 0 auto;
    }
    .logo {
      font-weight: 700;
      font-size: 1.8rem;
      letter-spacing: -0.5px;
      color: var(--primary-obsidian);
    }
    .logo span {
      color: var(--accent);
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .nav-links a {
      color: var(--text-body);
      font-weight: 500;
      font-size: 0.95rem;
      position: relative;
      padding-bottom: 4px;
      transition: color var(--transition-smooth);
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: 0;
      width: 0;
      height: 2px;
      background: var(--accent);
      transition: width var(--transition-smooth);
    }
    .nav-links a:hover {
      color: var(--accent);
    }
    .nav-links a:hover::after {
      width: 100%;
    }
    .hamburger {
      display: none;
      background: none;
      border: none;
      font-size: 1.8rem;
      color: var(--primary-obsidian);
    }
    .mobile-menu {
      display: none;
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
      }
      .hamburger {
        display: block;
      }
      .mobile-menu {
        display: flex;
        flex-direction: column;
        position: fixed;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: white;
        z-index: 49;
        justify-content: center;
        align-items: center;
        gap: 30px;
        opacity: 0;
        transform: translateY(-100%);
        transition: opacity 0.3s ease, transform 0.3s ease;
        pointer-events: none;
      }
      .mobile-menu.active {
        opacity: 1;
        transform: translateY(0);
        pointer-events: auto;
      }
    }
    /* 网格系统 */
    .section {
      padding: 100px 0;
    }
    @media (max-width: 768px) {
      .section {
        padding: 60px 0;
      }
      html {
        font-size: 15px;
      }
    }
    .flex-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .flex-grid.two-cols {
      grid-template-columns: repeat(2, 1fr);
    }
    @media (max-width: 1024px) {
      .flex-grid, .flex-grid.two-cols {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 640px) {
      .flex-grid, .flex-grid.two-cols {
        grid-template-columns: 1fr;
      }
    }
    /* 排版 */
    h1 {
      font-size: 3rem;
      font-weight: 700;
      letter-spacing: -0.5px;
      line-height: 1.2;
      color: var(--text-primary);
    }
    h2 {
      font-size: 2.25rem;
      font-weight: 600;
      color: var(--text-primary);
      margin-bottom: 16px;
    }
    h3 {
      font-size: 1.5rem;
      font-weight: 600;
      color: var(--text-primary);
    }
    @media (max-width: 768px) {
      h1 {
        font-size: 2.3rem;
      }
      h2 {
        font-size: 1.8rem;
      }
    }
    /* 卡片 */
    .card {
      background: #ffffff;
      border: 1px solid var(--border-default);
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      transition: all var(--transition-smooth);
      overflow: hidden;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 32px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      transition: all var(--transition-smooth);
      cursor: pointer;
      border: none;
      background: none;
    }
    .btn-primary {
      background: var(--accent);
      color: white;
    }
    .btn-primary:hover {
      background: #6a28a8;
      box-shadow: 0 6px 18px rgba(123, 47, 190, 0.3);
    }
    .btn-outline {
      border: 2px solid var(--accent);
      color: var(--accent);
      background: transparent;
    }
    .btn-outline:hover {
      background: var(--accent);
      color: white;
    }
    .icon-box {
      width: 48px;
      height: 48px;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    footer {
      background: var(--primary-obsidian);
      color: #AAAAAA;
      padding: 60px 0 30px;
    }
    .stat-number {
      font-family: 'Inter', sans-serif;
      font-weight: 700;
      font-size: 2.5rem;
      color: var(--accent);
    }
    .fade-up {
      opacity: 0;
      transform: translateY(24px);
      transition: opacity 0.6s ease-out, transform 0.6s ease-out;
    }
    .fade-up.visible {
      opacity: 1;
      transform: translateY(0);
    }

@media (max-width: 768px) {
          #hero .container { grid-template-columns: 1fr; text-align: center; }
          #hero img { order: -1; margin-bottom: 24px; }
        }