/* roulang page: index */
/* 设计变量与全局重置 */
    :root {
      --primary-red: #E53935;
      --deep-charcoal: #1E1E1E;
      --champion-gold: #FFB300;
      --warm-white: #FAFAF5;
      --pure-white: #FFFFFF;
      --mid-gray: #616161;
      --light-gray: #E0E0E0;
      --card-shadow: 0 2px 12px rgba(0,0,0,0.06);
      --card-hover-shadow: 0 8px 24px rgba(0,0,0,0.10);
      --border-radius-card: 12px;
      --border-radius-btn: 8px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Noto Sans SC", sans-serif;
      --font-number: "Inter", "SF Pro Display", system-ui, sans-serif;
      --transition-smooth: all 0.25s ease;
    }
    
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    
    html {
      scroll-behavior: smooth;
    }
    
    body {
      font-family: var(--font-sans);
      background-color: var(--warm-white);
      color: var(--deep-charcoal);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition-smooth);
    }
    
    button, .btn {
      cursor: pointer;
      font-family: var(--font-sans);
      transition: var(--transition-smooth);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      border: none;
      font-weight: 600;
    }
    
    /* 容器与布局 */
    .container-custom {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 24px;
      padding-right: 24px;
    }
    
    /* 导航样式 */
    .site-header {
      position: sticky;
      top: 0;
      background: var(--pure-white);
      border-bottom: 1px solid var(--light-gray);
      z-index: 50;
      height: 64px;
      transition: box-shadow 0.3s ease;
    }
    .site-header.scrolled {
      box-shadow: 0 4px 12px rgba(0,0,0,0.04);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
    }
    .logo-area {
      display: flex;
      align-items: baseline;
      gap: 8px;
    }
    .logo-text {
      font-size: 1.5rem;
      font-weight: 700;
      color: var(--deep-charcoal);
      letter-spacing: -0.3px;
    }
    .logo-domain {
      font-size: 0.75rem;
      color: var(--mid-gray);
      font-weight: 400;
    }
    .nav-menu {
      display: flex;
      gap: 2rem;
      list-style: none;
      font-weight: 500;
      color: var(--deep-charcoal);
    }
    .nav-menu a {
      font-size: 0.95rem;
      padding: 0.25rem 0;
      border-bottom: 2px solid transparent;
    }
    .nav-menu a:hover {
      color: var(--primary-red);
      border-bottom-color: var(--primary-red);
    }
    .nav-cta-btn {
      background: var(--primary-red);
      color: white;
      padding: 8px 20px;
      border-radius: var(--border-radius-btn);
      font-size: 0.9rem;
      font-weight: 600;
      white-space: nowrap;
    }
    .nav-cta-btn:hover {
      background: #C62828;
      transform: scale(1.03);
    }
    .burger-icon {
      display: none;
      font-size: 1.8rem;
      cursor: pointer;
      color: var(--deep-charcoal);
    }
    .mobile-menu {
      display: none;
      position: absolute;
      top: 64px;
      left: 0;
      width: 100%;
      background: var(--pure-white);
      border-bottom: 1px solid var(--light-gray);
      padding: 1.5rem;
      flex-direction: column;
      gap: 1.5rem;
      list-style: none;
      box-shadow: 0 8px 20px rgba(0,0,0,0.05);
    }
    .mobile-menu.active {
      display: flex;
    }
    
    /* 按钮系统 */
    .btn-primary {
      background: var(--primary-red);
      color: white;
      padding: 12px 28px;
      border-radius: var(--border-radius-btn);
      font-size: 0.95rem;
      box-shadow: 0 4px 10px rgba(229,57,53,0.25);
    }
    .btn-primary:hover {
      background: #C62828;
      transform: scale(1.03);
    }
    .btn-outline-gold {
      border: 2px solid var(--champion-gold);
      background: transparent;
      color: var(--deep-charcoal);
      padding: 12px 28px;
      border-radius: var(--border-radius-btn);
      font-size: 0.95rem;
    }
    .btn-outline-gold:hover {
      background: var(--champion-gold);
      color: var(--deep-charcoal);
      transform: scale(1.03);
    }
    .btn-gold-fill {
      background: var(--champion-gold);
      color: var(--deep-charcoal);
      padding: 16px 36px;
      border-radius: var(--border-radius-btn);
      font-weight: 700;
      font-size: 1.1rem;
    }
    .btn-gold-fill:hover {
      background: #FFA000;
      transform: scale(1.03);
    }
    
    /* 板块间距 */
    .section-padding {
      padding: 80px 0;
    }
    @media (max-width: 640px) {
      .section-padding {
        padding: 48px 0;
      }
    }
    
    /* 卡片基础 */
    .card {
      background: var(--pure-white);
      border-radius: var(--border-radius-card);
      box-shadow: var(--card-shadow);
      padding: 28px;
      transition: var(--transition-smooth);
    }
    .card:hover {
      box-shadow: var(--card-hover-shadow);
      transform: translateY(-4px);
    }
    
    /* 数据大字 */
    .stat-number {
      font-family: var(--font-number);
      font-size: 48px;
      font-weight: 800;
      color: var(--champion-gold);
      line-height: 1.1;
    }
    
    /* 深色背景区块 */
    .bg-dark {
      background-color: var(--deep-charcoal);
      color: var(--warm-white);
    }
    
    /* FAQ 手风琴细节 */
    .faq-item {
      border-bottom: 1px solid var(--light-gray);
      padding: 16px 0;
    }
    .faq-question {
      font-weight: 700;
      font-size: 1.1rem;
      display: flex;
      align-items: baseline;
      gap: 12px;
      cursor: pointer;
      color: var(--deep-charcoal);
    }
    .faq-question .q-mark {
      color: var(--primary-red);
      font-weight: 800;
    }
    .faq-answer {
      padding-left: 28px;
      color: var(--mid-gray);
      margin-top: 8px;
    }
    
    /* 响应式调整 */
    @media (max-width: 1024px) {
      .nav-menu { display: none; }
      .burger-icon { display: block; }
      .nav-cta-btn { display: none; }
    }
    @media (min-width: 1025px) {
      .mobile-menu { display: none !important; }
    }
    @media (max-width: 640px) {
      .site-header { height: 56px; }
      .mobile-menu { top: 56px; }
      .stat-number { font-size: 36px; }
      .btn-primary, .btn-outline-gold { width: 100%; justify-content: center; }
    }