/* roulang page: index */
/* 自定义 CSS 变量与全局样式 */
    :root {
      --primary: #E8452D;
      --primary-hover: #C0392B;
      --secondary: #1A1A2E;
      --accent: #F6C90E;
      --bg-light: #FAFAFA;
      --card-white: #FFFFFF;
      --text-main: #1A1A2E;
      --text-body: #3A3A4A;
      --text-muted: #6B6B7B;
      --border-light: #E8E8EC;
      --shadow-card: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-card-hover: 0 12px 32px rgba(232,69,45,0.15);
      --radius-card: 20px;
      --radius-small: 12px;
      --radius-button: 50px;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', system-ui, -apple-system, sans-serif;
      --font-numbers: 'Inter', 'SF Pro Display', system-ui, sans-serif;
      --transition-smooth: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    }
    
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    
    html {
      scroll-behavior: smooth;
    }
    
    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-body);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }
    
    .container {
      max-width: 1200px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    
    /* 导航毛玻璃与交互 */
    .header-blur {
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-light);
      transition: box-shadow 0.3s ease;
    }
    .header-scrolled {
      box-shadow: 0 4px 20px rgba(0,0,0,0.04);
    }
    
    .nav-link {
      color: var(--text-main);
      font-weight: 500;
      transition: color 0.2s;
      position: relative;
    }
    .nav-link:hover, .nav-link:focus-visible {
      color: var(--primary);
      outline: none;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--primary);
      transition: width 0.2s ease;
    }
    .nav-link:hover::after, .nav-link:focus-visible::after {
      width: 100%;
    }
    
    /* 按钮系统 */
    .btn-primary {
      background-color: var(--primary);
      color: white;
      border-radius: var(--radius-button);
      padding: 0.875rem 2rem;
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: var(--transition-smooth);
      box-shadow: 0 4px 12px rgba(232,69,45,0.2);
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      background-color: var(--primary-hover);
      transform: translateY(-2px);
      box-shadow: 0 8px 18px rgba(232,69,45,0.3);
    }
    
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      border-radius: var(--radius-button);
      padding: 0.875rem 2rem;
      font-weight: 600;
      transition: var(--transition-smooth);
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
      transform: translateY(-2px);
    }
    
    .btn-accent {
      background: var(--accent);
      color: var(--secondary);
      border-radius: var(--radius-button);
      padding: 0.875rem 2rem;
      font-weight: 700;
      transition: var(--transition-smooth);
      box-shadow: 0 4px 12px rgba(246,201,14,0.25);
    }
    .btn-accent:hover {
      background: #e5b80c;
      transform: translateY(-2px);
      box-shadow: 0 8px 18px rgba(246,201,14,0.4);
    }
    
    .btn-white-outline {
      background: transparent;
      border: 2px solid white;
      color: white;
      border-radius: var(--radius-button);
      padding: 0.875rem 2rem;
      font-weight: 600;
      transition: var(--transition-smooth);
    }
    .btn-white-outline:hover {
      background: white;
      color: var(--secondary);
      transform: translateY(-2px);
    }
    
    /* 卡片与徽章 */
    .service-card, .solution-card {
      background: var(--card-white);
      border-radius: var(--radius-card);
      padding: 2rem;
      box-shadow: var(--shadow-card);
      transition: var(--transition-smooth);
      height: 100%;
      border: 1px solid rgba(0,0,0,0.02);
    }
    .service-card:hover, .solution-card:hover {
      transform: translateY(-8px);
      box-shadow: var(--shadow-card-hover);
    }
    
    .icon-circle {
      background: var(--primary);
      width: 64px;
      height: 64px;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: white;
      font-size: 28px;
      transition: transform 0.2s;
    }
    .service-card:hover .icon-circle {
      transform: scale(1.05);
    }
    
    .data-badge {
      background: #F0F0F5;
      border-radius: 16px;
      padding: 1.5rem;
      text-align: center;
      transition: var(--transition-smooth);
    }
    .data-number {
      font-family: var(--font-numbers);
      font-weight: 800;
      font-size: 3rem;
      line-height: 1.2;
      background: linear-gradient(180deg, #E8452D, #C0392B);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      display: inline-block;
    }
    
    .hero-badge {
      background: rgba(255,255,255,0.1);
      backdrop-filter: blur(8px);
      border-radius: 40px;
      padding: 0.5rem 1.2rem;
      color: white;
      font-weight: 500;
      display: inline-flex;
      align-items: center;
      gap: 0.5rem;
    }
    
    /* FAQ 手风琴 */
    .faq-item {
      background: var(--card-white);
      border-radius: var(--radius-small);
      margin-bottom: 1rem;
      box-shadow: 0 1px 6px rgba(0,0,0,0.04);
      overflow: hidden;
      transition: all 0.3s ease;
    }
    .faq-question {
      padding: 1.25rem 1.5rem;
      font-weight: 600;
      font-size: 1.125rem;
      color: var(--text-main);
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      background: white;
      border: none;
      width: 100%;
      text-align: left;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.35s ease;
      background: #FAFAFA;
      padding: 0 1.5rem;
      color: var(--text-body);
      line-height: 1.7;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding: 1rem 1.5rem 1.5rem;
    }
    .faq-icon {
      transition: transform 0.3s;
      font-size: 1.2rem;
      color: var(--primary);
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    
    /* 移动端菜单 */
    .mobile-menu {
      display: none;
      flex-direction: column;
      background: white;
      position: absolute;
      top: 100%;
      left: 0;
      width: 100%;
      padding: 1.5rem;
      box-shadow: 0 20px 30px rgba(0,0,0,0.1);
      border-top: 1px solid var(--border-light);
      animation: fadeIn 0.2s ease;
    }
    .mobile-menu.open {
      display: flex;
    }
    @keyframes fadeIn {
      from { opacity: 0; transform: translateY(-5px); }
      to { opacity: 1; transform: translateY(0); }
    }
    
    /* Hero动态背景 */
    .hero-pattern {
      background: linear-gradient(135deg, #1A1A2E 0%, #2D2D44 100%);
      position: relative;
      overflow: hidden;
    }
    .hero-pattern::before {
      content: "";
      position: absolute;
      top: 0; left: 0; right: 0; bottom: 0;
      background-image: radial-gradient(circle at 20% 30%, rgba(232,69,45,0.2) 0%, transparent 45%),
                        radial-gradient(circle at 80% 70%, rgba(246,201,14,0.15) 0%, transparent 50%);
      pointer-events: none;
    }
    
    /* 响应式调整 */
    @media (max-width: 1023px) {
      .desktop-menu { display: none !important; }
      .menu-toggle { display: flex !important; }
    }
    @media (min-width: 1024px) {
      .menu-toggle { display: none !important; }
      .desktop-menu { display: flex !important; }
    }