/* roulang page: index */
:root {
      /* 主色推导 */
      --star-blue: #1B2A4A;
      --star-orange: #FF6B35;
      --star-purple: #7B4B9A;
      --star-green: #00B578;
      --star-warning: #FF9F0A;
      --star-error: #FA5151;
      
      /* 背景与表面 */
      --bg-starlight: #F4F6FC;
      --bg-white: #FFFFFF;
      --bg-dark: #1B2A4A;
      --bg-footer: #1A2338;
      
      /* 文字色 */
      --text-primary: #1F2329;
      --text-body: #3A4050;
      --text-secondary: #5A6275;
      --text-muted: #86909C;
      --text-white: #FFFFFF;
      
      /* 形状 */
      --radius-card: 16px;
      --radius-btn: 50px;
      --radius-sm: 12px;
      
      /* 阴影 */
      --shadow-card: 0 4px 20px rgba(27,42,74,0.06);
      --shadow-card-hover: 0 8px 30px rgba(27,42,74,0.12);
      
      /* 间距 */
      --space-section: 100px;
      --space-container: 24px;
      
      /* 过渡 */
      --transition-fast: 200ms cubic-bezier(0.4, 0, 0.2, 1);
      --transition-smooth: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    }
    
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    
    html {
      scroll-behavior: smooth;
    }
    
    body {
      font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--bg-starlight);
      color: var(--text-body);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 var(--space-container);
    }
    
    /* 导航 */
    #nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(27, 42, 74, 0.85);
      backdrop-filter: blur(10px);
      -webkit-backdrop-filter: blur(10px);
      z-index: 1000;
      transition: background var(--transition-smooth), box-shadow var(--transition-smooth);
      border-bottom: 1px solid rgba(255,255,255,0.08);
    }
    
    #nav.scrolled {
      background: var(--star-blue);
      box-shadow: 0 4px 20px rgba(0,0,0,0.15);
    }
    
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    
    .logo {
      font-size: 1.8rem;
      font-weight: 700;
      color: white;
      text-decoration: none;
      letter-spacing: 1px;
      display: flex;
      align-items: center;
    }
    .logo i {
      color: var(--star-orange);
      margin-right: 10px;
      font-size: 2rem;
    }
    
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 2rem;
    }
    
    .nav-link {
      color: rgba(255,255,255,0.85);
      text-decoration: none;
      font-weight: 500;
      font-size: 1rem;
      position: relative;
      padding: 0.25rem 0;
      transition: color var(--transition-fast);
    }
    
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 50%;
      transform: translateX(-50%);
      width: 0;
      height: 2px;
      background: var(--star-orange);
      transition: width var(--transition-fast);
    }
    
    .nav-link:hover,
    .nav-link.active {
      color: white;
    }
    
    .nav-link:hover::after,
    .nav-link.active::after {
      width: 60%;
    }
    
    .nav-cta {
      background: var(--star-orange);
      color: white;
      padding: 0.6rem 1.8rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: background var(--transition-fast), box-shadow var(--transition-fast);
      text-decoration: none;
      margin-left: 1rem;
    }
    
    .nav-cta:hover {
      background: #e55a2b;
      box-shadow: 0 0 15px rgba(255,107,53,0.5);
    }
    
    .hamburger {
      display: none;
      flex-direction: column;
      cursor: pointer;
      gap: 5px;
    }
    .hamburger span {
      width: 25px;
      height: 2px;
      background: white;
      border-radius: 2px;
      transition: var(--transition-fast);
    }
    
    /* 移动端导航 */
    @media (max-width: 768px) {
      .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        background: var(--star-blue);
        flex-direction: column;
        padding: 2rem;
        gap: 2rem;
        transform: translateY(-150%);
        transition: transform 0.35s ease;
        box-shadow: 0 10px 25px rgba(0,0,0,0.2);
      }
      .nav-menu.active {
        transform: translateY(0);
      }
      .hamburger {
        display: flex;
      }
      .nav-cta {
        margin-left: 0;
        text-align: center;
        width: 100%;
      }
    }
    
    /* Hero */
    #hero {
      padding: 140px 0 100px;
      background-color: var(--bg-starlight);
      overflow: hidden;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 3rem;
    }
    .hero-text {
      flex: 1 1 55%;
    }
    .hero-visual {
      flex: 1 1 45%;
      position: relative;
      min-height: 380px;
    }
    .hero-badge {
      font-size: 0.9rem;
      color: var(--text-secondary);
      margin-bottom: 1rem;
    }
    h1 {
      font-size: 3rem;
      font-weight: 700;
      line-height: 1.2;
      color: var(--star-blue);
      margin-bottom: 1.5rem;
    }
    h1 span {
      color: var(--star-orange);
    }
    .hero-desc {
      font-size: 1.125rem;
      color: var(--text-secondary);
      margin-bottom: 2rem;
    }
    .btn-group {
      display: flex;
      gap: 1rem;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--star-orange);
      color: white;
      padding: 0.9rem 2.4rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      text-decoration: none;
      transition: all var(--transition-fast);
      display: inline-block;
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      background: #e55a2b;
      box-shadow: 0 8px 20px rgba(255,107,53,0.45);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--star-blue);
      color: var(--star-blue);
      padding: 0.9rem 2.4rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      text-decoration: none;
      transition: all var(--transition-fast);
    }
    .btn-outline:hover {
      background: rgba(27,42,74,0.05);
    }
    
    .hero-visual img {
      width: 100%;
      height: auto;
      border-radius: 32px;
      box-shadow: var(--shadow-card-hover);
    }
    
    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
      }
      h1 {
        font-size: 2.4rem;
      }
    }
    
    /* 通用板块 */
    section {
      padding: var(--space-section) 0;
    }
    .section-title {
      font-size: 2.25rem;
      font-weight: 600;
      color: var(--star-blue);
      margin-bottom: 1rem;
      text-align: center;
    }
    .section-sub {
      color: var(--text-secondary);
      text-align: center;
      margin-bottom: 3rem;
    }
    
    /* 核心优势 左对齐图标卡片 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 30px;
    }
    .feature-card {
      background: var(--bg-white);
      padding: 2rem;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      transition: all var(--transition-smooth);
      display: flex;
      gap: 1.5rem;
      align-items: flex-start;
    }
    .feature-icon {
      font-size: 2.2rem;
      color: var(--star-orange);
      width: 48px;
      text-align: center;
    }
    .feature-card h3 {
      font-size: 1.25rem;
      font-weight: 600;
      color: var(--star-blue);
      margin-bottom: 0.5rem;
    }
    .feature-card p {
      color: var(--text-body);
    }
    .feature-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    
    /* 解决方案大卡片 */
    .solutions-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 30px;
    }
    .solution-card {
      background: white;
      border-radius: var(--radius-card);
      overflow: hidden;
      display: flex;
      box-shadow: var(--shadow-card);
      transition: var(--transition-smooth);
    }
    .solution-img {
      width: 45%;
      background: #eef2f8;
    }
    .solution-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
    }
    .solution-text {
      padding: 2rem;
      display: flex;
      flex-direction: column;
      justify-content: center;
    }
    .solution-text h3 {
      color: var(--star-blue);
    }
    .solution-link {
      color: var(--star-orange);
      font-weight: 600;
      margin-top: 1rem;
      text-decoration: none;
      transition: gap 0.2s;
    }
    .solution-card:hover {
      transform: translateY(-5px);
      box-shadow: var(--shadow-card-hover);
    }
    
    /* 数据深色区 */
    .dark-bg {
      background: var(--bg-dark);
      color: white;
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      text-align: center;
      gap: 2rem;
    }
    .stat-number {
      font-size: 3rem;
      font-weight: 700;
      color: var(--star-orange);
    }
    
    /* FAQ */
    .faq-item {
      background: white;
      border-radius: var(--radius-card);
      margin-bottom: 1rem;
      padding: 1.2rem 1.8rem;
      box-shadow: 0 2px 12px rgba(0,0,0,0.04);
    }
    .faq-question {
      font-weight: 600;
      color: var(--star-blue);
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    
    /* CTA */
    .cta-block {
      text-align: center;
    }
    
    /* Footer */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 2rem;
    }
    footer {
      background: var(--bg-footer);
      color: #ccc;
      padding: 60px 0 20px;
    }
    
    @media (max-width: 1024px) {
      .features-grid { grid-template-columns: repeat(2,1fr); }
    }
    @media (max-width: 768px) {
      .features-grid, .solutions-grid, .stats-grid, .footer-grid {
        grid-template-columns: 1fr;
      }
      .solution-card {
        flex-direction: column;
      }
    }