/* roulang page: index */
:root {
      --primary: #E53935;
      --primary-dark: #C62828;
      --secondary: #1B1B2F;
      --accent: #FFB300;
      --bg-light: #F8F9FA;
      --text-main: #333333;
      --text-muted: #5F6B7A;
      --white: #FFFFFF;
      --card-shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
      --card-shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.12);
      --radius-lg: 16px;
      --radius-full: 50px;
      --font-title: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --font-body: 'PingFang SC', 'Microsoft YaHei', sans-serif;
      --font-number: 'Inter', 'Roboto', sans-serif;
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      font-family: var(--font-body);
      color: var(--text-main);
      background-color: var(--bg-light);
      line-height: 1.65;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    h1, h2, h3, .font-title {
      font-family: var(--font-title);
      font-weight: 700;
      letter-spacing: -0.02em;
    }
    .font-number {
      font-family: var(--font-number);
      font-weight: 600;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .site-header {
      position: sticky;
      top: 0;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      z-index: 50;
      border-bottom: 1px solid rgba(0,0,0,0.03);
      transition: box-shadow 0.3s;
    }
    .site-header.scrolled {
      box-shadow: 0 8px 25px rgba(0,0,0,0.05);
    }
    .nav-link {
      color: var(--text-main);
      font-weight: 500;
      text-decoration: none;
      padding: 8px 0;
      transition: color 0.2s;
      font-size: 15px;
    }
    .nav-link:hover {
      color: var(--primary);
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      border-radius: var(--radius-full);
      padding: 12px 28px;
      font-weight: 600;
      text-decoration: none;
      display: inline-block;
      transition: background 0.25s, transform 0.2s;
      box-shadow: 0 4px 12px rgba(229,57,53,0.3);
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: scale(1.03);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      border-radius: var(--radius-full);
      padding: 11px 26px;
      font-weight: 600;
      text-decoration: none;
      display: inline-block;
      transition: all 0.25s;
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
    }
    /* 板块间距 */
    .section {
      padding: 80px 0;
    }
    @media (max-width: 768px) {
      .section {
        padding: 56px 0;
      }
    }
    /* cards */
    .card-white {
      background: var(--white);
      border-radius: var(--radius-lg);
      box-shadow: var(--card-shadow);
      transition: all 0.3s ease;
      height: 100%;
    }
    .card-white:hover {
      transform: translateY(-4px);
      box-shadow: var(--card-shadow-hover);
    }
    .dark-card {
      background: rgba(255,255,255,0.05);
      backdrop-filter: blur(10px);
      border-radius: var(--radius-lg);
      border: 1px solid rgba(255,255,255,0.1);
    }
    /* hero 渐变 */
    .hero-gradient {
      background: linear-gradient(135deg, #E53935 0%, #1B1B2F 100%);
      position: relative;
      overflow: hidden;
    }
    .hero-gradient::after {
      content: '';
      position: absolute;
      top: -20%;
      right: -10%;
      width: 60%;
      height: 120%;
      background: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 200 200" opacity="0.08"><path d="M45 0L90 80H0L45 0z" fill="white"/></svg>') repeat;
      transform: rotate(25deg);
      pointer-events: none;
    }
    .footer-dark {
      background: var(--secondary);
      color: rgba(255,255,255,0.75);
    }
    .footer-dark a {
      color: rgba(255,255,255,0.8);
      text-decoration: none;
      transition: color 0.2s;
    }
    .footer-dark a:hover {
      color: white;
    }
    /* 响应式底部导航 */
    @media (max-width: 768px) {
      .desktop-nav {
        display: none !important;
      }
      .mobile-bottom-nav {
        display: flex;
        position: fixed;
        bottom: 0;
        left: 0;
        width: 100%;
        background: white;
        border-top: 1px solid #e5e7eb;
        box-shadow: 0 -4px 15px rgba(0,0,0,0.06);
        z-index: 100;
        justify-content: space-around;
        align-items: center;
        padding: 8px 16px 12px;
      }
      .mobile-nav-item {
        display: flex;
        flex-direction: column;
        align-items: center;
        color: #6b7280;
        font-size: 12px;
        text-decoration: none;
        font-weight: 500;
        transition: color 0.2s;
      }
      .mobile-nav-item.active {
        color: var(--primary);
      }
      .mobile-cta-btn {
        background: var(--primary);
        color: white;
        border-radius: 30px;
        padding: 10px 20px;
        font-weight: 700;
        box-shadow: 0 6px 14px rgba(229,57,53,0.4);
        margin-top: -18px;
        text-decoration: none;
      }
      .hero-title {
        font-size: 2rem !important;
      }
    }
    @media (min-width: 769px) {
      .mobile-bottom-nav {
        display: none;
      }
    }
    /* FAQ accordion */
    .faq-item {
      border-bottom: 1px solid #eef0f2;
    }
    .faq-question {
      cursor: pointer;
      padding: 20px 8px;
      font-weight: 700;
      font-size: 18px;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.3s;
      background: #f9fafb;
      border-radius: 0 0 12px 12px;
      padding: 0 16px;
      color: #4b5563;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding: 16px;
    }
    .testimonial-card {
      background: white;
      border-radius: 20px;
      padding: 28px;
      box-shadow: 0 8px 24px rgba(0,0,0,0.04);
    }
    .quote-line {
      border-left: 4px solid var(--primary);
      padding-left: 20px;
      font-style: italic;
    }