/* roulang page: index */
/* 自定义设计变量与全局样式 */
    :root {
      --primary: #FF6B4A;
      --primary-hover: #FF8A6E;
      --secondary-dark: #1E1E24;
      --bg-warm: #FFF3EC;
      --accent: #00C9A7;
      --white: #FFFFFF;
      --text-body: #2D2D34;
      --text-muted: #6B6B78;
      --border-light: rgba(0,0,0,0.04);
      --shadow-card: 0 4px 24px rgba(0,0,0,0.04);
      --shadow-card-hover: 0 8px 32px rgba(0,0,0,0.08);
      --radius-md: 12px;
      --radius-lg: 16px;
      --radius-btn: 8px;
      --font-sans: -apple-system, "PingFang SC", "Microsoft YaHei", "Segoe UI", sans-serif;
    }

    * {
      box-sizing: border-box;
    }

    body {
      margin: 0;
      font-family: var(--font-sans);
      background-color: var(--bg-warm);
      color: var(--text-body);
      line-height: 1.7;
      -webkit-font-smoothing: antialiased;
      display: flex;
      min-height: 100vh;
    }

    /* 左侧导航桌面样式 */
    .app-shell-nav {
      position: fixed;
      left: 0;
      top: 0;
      bottom: 0;
      width: 80px;
      background-color: var(--secondary-dark);
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 24px 0;
      z-index: 40;
      box-shadow: 2px 0 12px rgba(0,0,0,0.08);
      transition: transform 0.3s ease;
    }

    .nav-logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--white);
      margin-bottom: 48px;
      letter-spacing: -0.5px;
      writing-mode: vertical-lr;
      text-orientation: mixed;
      cursor: pointer;
      user-select: none;
    }
    .nav-logo span {
      color: var(--primary);
    }

    .nav-menu {
      display: flex;
      flex-direction: column;
      gap: 28px;
      align-items: center;
      flex: 1;
    }

    .nav-item {
      display: flex;
      flex-direction: column;
      align-items: center;
      color: rgba(255,255,255,0.7);
      text-decoration: none;
      font-size: 13px;
      font-weight: 500;
      transition: color 0.25s ease, transform 0.2s;
      position: relative;
      padding: 4px 0;
      letter-spacing: 0.3px;
    }

    .nav-item i {
      font-size: 22px;
      margin-bottom: 4px;
      transition: color 0.25s ease;
    }

    .nav-item:hover {
      color: var(--primary);
      transform: translateX(2px);
    }

    .nav-item.active {
      color: var(--primary);
    }
    .nav-item.active::before {
      content: '';
      position: absolute;
      left: -16px;
      top: 0;
      bottom: 0;
      width: 3px;
      background-color: var(--primary);
      border-radius: 0 4px 4px 0;
    }

    /* 主内容区域 */
    .main-content {
      margin-left: 80px;
      flex: 1;
      width: calc(100% - 80px);
      background-color: var(--bg-warm);
    }

    /* 移动端导航按钮 */
    .mobile-nav-toggle {
      display: none;
      position: fixed;
      top: 16px;
      left: 16px;
      z-index: 50;
      background: var(--secondary-dark);
      color: white;
      border: none;
      width: 44px;
      height: 44px;
      border-radius: 12px;
      font-size: 22px;
      cursor: pointer;
      box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    }

    /* 移动端抽屉菜单 */
    .mobile-drawer {
      position: fixed;
      top: 0;
      left: 0;
      bottom: 0;
      width: 260px;
      background: var(--secondary-dark);
      z-index: 100;
      transform: translateX(-100%);
      transition: transform 0.3s ease;
      display: flex;
      flex-direction: column;
      padding: 32px 24px;
      box-shadow: 4px 0 24px rgba(0,0,0,0.2);
    }
    .mobile-drawer.open {
      transform: translateX(0);
    }
    .drawer-close {
      align-self: flex-end;
      background: none;
      border: none;
      color: white;
      font-size: 28px;
      margin-bottom: 32px;
      cursor: pointer;
    }
    .drawer-nav {
      display: flex;
      flex-direction: column;
      gap: 24px;
    }
    .drawer-nav a {
      color: rgba(255,255,255,0.8);
      font-size: 18px;
      font-weight: 500;
      text-decoration: none;
      display: flex;
      align-items: center;
      gap: 12px;
      transition: color 0.2s;
    }
    .drawer-nav a:hover, .drawer-nav a.active {
      color: var(--primary);
    }

    /* 通用容器 */
    .section-container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 80px 32px;
    }

    /* 卡片与组件补充 */
    .card-basic {
      background: var(--white);
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-card);
      transition: all 0.3s ease;
    }
    .card-basic:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }

    .btn-primary {
      background: var(--primary);
      color: white;
      font-weight: 600;
      border-radius: var(--radius-btn);
      padding: 14px 32px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: background 0.3s ease, transform 0.2s;
      border: none;
      cursor: pointer;
      text-decoration: none;
      letter-spacing: 0.3px;
    }
    .btn-primary:hover {
      background: var(--accent);
      transform: scale(1.02);
    }

    .btn-outline-light {
      background: transparent;
      border: 1px solid white;
      color: white;
      font-weight: 500;
      border-radius: var(--radius-btn);
      padding: 12px 28px;
      transition: all 0.3s;
      text-decoration: none;
      display: inline-block;
    }
    .btn-outline-light:hover {
      background: rgba(255,255,255,0.15);
      border-color: rgba(255,255,255,0.8);
    }

    /* 背景图叠加层 */
    .hero-overlay {
      background: linear-gradient(135deg, rgba(255,107,74,0.2) 0%, rgba(30,30,36,0.75) 80%);
    }

    /* 滚动动画初始隐藏 */
    .fade-up {
      opacity: 0;
      transform: translateY(20px);
      transition: opacity 0.6s ease, transform 0.6s ease;
    }
    .fade-up.visible {
      opacity: 1;
      transform: translateY(0);
    }

    @media (max-width: 1024px) {
      .app-shell-nav {
        display: none;
      }
      .main-content {
        margin-left: 0;
        width: 100%;
      }
      .mobile-nav-toggle {
        display: flex;
        align-items: center;
        justify-content: center;
      }
      .section-container {
        padding: 64px 20px;
      }
    }

    @media (max-width: 768px) {
      .hero-title {
        font-size: 36px;
      }
      .grid-3-col {
        grid-template-columns: 1fr;
      }
    }