/* roulang page: index */
/* ---- 设计变量与全局重置 ---- */
    :root {
      --primary-deep-green: #1E3A2F;
      --accent-copper-gold: #C49A6C;
      --accent-copper-dark: #A87D4E;
      --bg-warm-white: #FAF8F5;
      --card-white: #FFFFFF;
      --text-primary: #1F2937;
      --text-secondary: #6B7280;
      --border-light: #E5E7EB;
      --shadow-xs: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-md: 0 12px 32px rgba(0,0,0,0.08);
      --radius-card: 16px;
      --radius-btn: 8px;
      --radius-badge: 20px;
      --font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --transition-smooth: 0.3s ease;
    }
    
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    
    html {
      scroll-behavior: smooth;
    }
    
    body {
      font-family: var(--font-family);
      font-size: 16px;
      font-weight: 400;
      line-height: 1.7;
      color: var(--text-primary);
      background-color: var(--bg-warm-white);
      overflow-x: hidden;
    }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    
    a {
      text-decoration: none;
      color: inherit;
    }
    
    .container {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 24px;
      padding-right: 24px;
      width: 100%;
    }
    
    /* ---- 导航 ---- */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: var(--card-white);
      z-index: 50;
      border-bottom: 1px solid rgba(0,0,0,0.03);
      box-shadow: 0 2px 8px rgba(0,0,0,0.02);
      display: flex;
      align-items: center;
    }
    
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    
    .logo {
      font-size: 1.8rem;
      font-weight: 700;
      letter-spacing: 1px;
      color: var(--primary-deep-green);
      display: flex;
      align-items: center;
      gap: 4px;
    }
    
    .logo i {
      font-size: 2rem;
      color: var(--accent-copper-gold);
    }
    
    .nav-links {
      display: flex;
      list-style: none;
      gap: 2.2rem;
      align-items: center;
      font-weight: 500;
      font-size: 1rem;
    }
    
    .nav-links a {
      color: #374151;
      position: relative;
      padding-bottom: 6px;
      transition: color var(--transition-smooth);
    }
    
    .nav-links a:hover {
      color: var(--primary-deep-green);
    }
    
    .nav-links a.active::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 100%;
      height: 2px;
      background-color: var(--accent-copper-gold);
    }
    
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 6px;
      cursor: pointer;
      background: transparent;
      border: none;
      width: 32px;
      height: 24px;
      justify-content: center;
    }
    
    .hamburger span {
      display: block;
      height: 2px;
      background: var(--primary-deep-green);
      border-radius: 2px;
      transition: 0.25s;
    }
    
    /* 移动端导航面板 */
    .mobile-menu {
      display: none;
    }
    
    @media (max-width: 768px) {
      .nav-links {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .mobile-menu {
        position: fixed;
        top: 0;
        right: 0;
        width: 80vw;
        max-width: 320px;
        height: 100vh;
        background: var(--primary-deep-green);
        z-index: 60;
        transform: translateX(100%);
        transition: transform 0.4s ease;
        display: flex;
        flex-direction: column;
        padding: 24px;
        box-shadow: -8px 0 20px rgba(0,0,0,0.15);
      }
      .mobile-menu.open {
        transform: translateX(0);
      }
      .mobile-menu .close-btn {
        align-self: flex-end;
        background: none;
        border: none;
        color: white;
        font-size: 2rem;
        cursor: pointer;
      }
      .mobile-menu a {
        color: white;
        font-size: 1.2rem;
        margin: 18px 0;
        font-weight: 500;
        border-bottom: 1px solid rgba(255,255,255,0.2);
        padding-bottom: 8px;
      }
    }
    
    /* ---- 通用板块间距 ---- */
    section {
      padding: 100px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 70px 0;
      }
    }
    
    h2 {
      font-size: 36px;
      font-weight: 600;
      letter-spacing: -0.3px;
      color: var(--primary-deep-green);
      margin-bottom: 16px;
    }
    
    @media (max-width: 768px) {
      h2 {
        font-size: 26px;
      }
    }
    
    .section-sub {
      font-size: 1.125rem;
      color: var(--text-secondary);
      margin-bottom: 48px;
      max-width: 700px;
    }
    
    /* 卡片系统 */
    .card {
      background: var(--card-white);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-xs);
      transition: all var(--transition-smooth);
      height: 100%;
      display: flex;
      flex-direction: column;
    }
    
    .card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-4px);
    }
    
    /* 按钮 */
    .btn-primary {
      background: var(--accent-copper-gold);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      display: inline-block;
      transition: background 0.25s;
      border: none;
      cursor: pointer;
      text-align: center;
    }
    .btn-primary:hover {
      background: var(--accent-copper-dark);
      color: white;
    }
    .btn-outline {
      border: 2px solid var(--accent-copper-gold);
      color: var(--accent-copper-gold);
      background: transparent;
      padding: 12px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      display: inline-block;
      transition: all 0.25s;
    }
    .btn-outline:hover {
      background: var(--accent-copper-gold);
      color: white;
    }
    
    .badge {
      background: var(--accent-copper-gold);
      color: white;
      border-radius: var(--radius-badge);
      padding: 6px 18px;
      font-size: 0.9rem;
      font-weight: 600;
      display: inline-block;
      letter-spacing: 0.3px;
    }
    
    /* Hero 渐变+网格纹理 */
    .hero {
      background: linear-gradient(135deg, var(--primary-deep-green) 0%, #0F2A1D 100%);
      position: relative;
      min-height: 90vh;
      display: flex;
      align-items: center;
      padding-top: 72px;
    }
    .hero::before {
      content: '';
      position: absolute;
      inset: 0;
      background-image: 
        linear-gradient(rgba(255,255,255,0.05) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255,255,255,0.05) 1px, transparent 1px);
      background-size: 40px 40px;
      pointer-events: none;
    }
    .hero-content {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
      align-items: center;
      position: relative;
      z-index: 2;
    }
    @media (max-width: 768px) {
      .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
      }
    }
    h1 {
      font-size: 52px;
      font-weight: 700;
      letter-spacing: -0.5px;
      color: white;
      line-height: 1.3;
      margin-bottom: 20px;
    }
    @media (max-width: 768px) {
      h1 { font-size: 32px; }
    }
    .hero-sub {
      color: rgba(255,255,255,0.85);
      font-size: 1.2rem;
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-image {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: 24px;
      min-height: 320px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.3);
    }
    
    /* 功能栅格 */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    @media (max-width: 1024px) { .grid-3 { grid-template-columns: repeat(2,1fr); } }
    @media (max-width: 768px) { .grid-3 { grid-template-columns: 1fr; } }
    
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2,1fr);
      gap: 32px;
      align-items: center;
    }
    @media (max-width: 768px) { .grid-2 { grid-template-columns: 1fr; } }
    
    .inline-badge {
      display: inline-flex;
      align-items: center;
      gap: 8px;
    }
    
    /* 手风琴FAQ */
    .faq-item {
      background: #F3F4F6;
      border-radius: 12px;
      margin-bottom: 12px;
      overflow: hidden;
    }
    .faq-title {
      padding: 20px 24px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    .faq-content {
      padding: 0 24px 20px;
      border-top: 1px solid var(--border-light);
      display: none;
    }
    .faq-item.active .faq-content {
      display: block;
    }
    .arrow {
      transition: transform 0.3s;
    }
    .faq-item.active .arrow {
      transform: rotate(180deg);
    }
    
    footer {
      background: var(--primary-deep-green);
      color: rgba(255,255,255,0.9);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 30px;
    }
    @media (max-width: 768px) { .footer-grid { grid-template-columns: 1fr; } }
    .footer-links a { color: #CBD5E0; display: block; margin: 6px 0; }