/* roulang page: index */
/* 设计变量与全局重置 */
    :root {
      --primary: #F04E23;
      --primary-dark: #D43D1A;
      --secondary: #1C1C1E;
      --bg: #F7F5F2;
      --card: #FFFFFF;
      --accent: #C7F800;
      --text: #2D2D2D;
      --text-light: #6B6B6B;
      --border-light: #E0E0E0;
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-img: 10px;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.06);
      --shadow-hover: 0 8px 30px rgba(0,0,0,0.10);
      --font-sans: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
    }
    
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    
    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.8;
      font-size: 1rem;
      -webkit-font-smoothing: antialiased;
    }
    
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 2rem;
    }
    
    /* 导航固定头部 */
    .navbar {
      position: sticky;
      top: 0;
      background: white;
      z-index: 50;
      height: 72px;
      display: flex;
      align-items: center;
      border-bottom: 1px solid rgba(0,0,0,0.05);
      transition: box-shadow 0.2s;
    }
    .navbar.scrolled {
      box-shadow: 0 4px 20px rgba(0,0,0,0.06);
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--secondary);
      letter-spacing: 0.5px;
      display: flex;
      align-items: center;
      gap: 0.5rem;
    }
    .logo i {
      color: var(--primary);
      font-size: 1.8rem;
    }
    .nav-links {
      display: flex;
      gap: 2rem;
      align-items: center;
    }
    .nav-links a {
      text-decoration: none;
      color: var(--text);
      font-weight: 500;
      transition: color 0.2s;
      font-size: 0.95rem;
    }
    .nav-links a:hover {
      color: var(--primary);
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 0.7rem 1.8rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      text-decoration: none;
      display: inline-block;
      transition: background 0.2s, transform 0.2s;
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: translateY(-2px);
    }
    .btn-secondary {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      padding: 0.7rem 1.8rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      text-decoration: none;
      transition: background 0.2s;
    }
    .btn-secondary:hover {
      background: rgba(240,78,35,0.1);
    }
    .btn-cta {
      background: var(--primary);
      color: white;
      padding: 0.95rem 2.5rem;
      font-size: 1.15rem;
      border-radius: var(--radius-btn);
      font-weight: 700;
      transition: 0.2s;
      border: none;
      cursor: pointer;
      display: inline-block;
      text-decoration: none;
    }
    .btn-cta:hover {
      background: var(--primary-dark);
      box-shadow: 0 0 15px var(--accent);
      transform: translateY(-3px);
    }
    
    /* 移动端菜单 */
    .hamburger {
      display: none;
      font-size: 1.8rem;
      cursor: pointer;
      color: var(--secondary);
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: var(--secondary);
      z-index: 100;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 2rem;
    }
    .mobile-menu a {
      color: white;
      font-size: 1.5rem;
      text-decoration: none;
    }
    .close-menu {
      position: absolute;
      top: 2rem;
      right: 2rem;
      font-size: 2rem;
      color: white;
      cursor: pointer;
    }
    
    /* 板块间距 */
    section {
      padding: 5rem 0;
    }
    
    h2 {
      font-weight: 700;
      font-size: clamp(2rem, 4vw, 2.75rem);
      margin-bottom: 1rem;
      color: var(--secondary);
    }
    .section-subtitle {
      color: var(--text-light);
      margin-bottom: 2.5rem;
      font-size: 1.125rem;
    }
    .decor-line {
      width: 40px;
      height: 3px;
      background: var(--primary);
      margin: 0.5rem 0 1.5rem;
    }
    
    /* 卡片通用 */
    .card {
      background: var(--card);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      padding: 2rem;
      transition: 0.25s;
    }
    .card:hover {
      box-shadow: var(--shadow-hover);
    }
    
    /* 图片样式 */
    .img-rounded {
      border-radius: var(--radius-img);
      width: 100%;
      height: auto;
      object-fit: cover;
    }
    
    @media (max-width: 1024px) {
      .container { padding: 0 1.5rem; }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: block; }
      .navbar { height: 60px; }
      section { padding: 3rem 0; }
    }