/* roulang page: index */
:root {
      --primary-charcoal: #1A1A1A;
      --accent-red: #C73E3A;
      --accent-red-hover: #A8322E;
      --accent-gold: #D4AF37;
      --bg-warm: #F7F5F2;
      --bg-dark: #121212;
      --card-bg: #FFFFFF;
      --card-border: #E8E5DF;
      --text-body: #3A3A3A;
      --text-muted: #6B6B6B;
      --text-light: #B0B0B0;
      --text-footer: #999999;
      --white: #FFFFFF;
      --shadow-light: 0 2px 12px rgba(0,0,0,0.04);
      --shadow-hover: 0 12px 28px rgba(0,0,0,0.08);
      --radius-sm: 6px;
      --radius-md: 8px;
      --transition: 0.25s ease-out;
      --max-width: 1280px;
      --nav-height-desktop: 72px;
      --nav-height-mobile: 60px;
    }

    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }

    html {
      scroll-behavior: smooth;
      scroll-padding-top: var(--nav-height-desktop);
    }

    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--bg-warm);
      color: var(--text-body);
      line-height: 1.8;
      font-weight: 400;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }

    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
      width: 100%;
    }

    h1, h2, h3 {
      font-weight: 700;
      line-height: 1.3;
      color: var(--primary-charcoal);
    }

    h1 {
      font-size: 48px;
      letter-spacing: -0.5px;
      font-weight: 700;
    }

    h2 {
      font-size: 36px;
      font-weight: 600;
      margin-bottom: 16px;
    }

    h3 {
      font-size: 22px;
      font-weight: 500;
      margin-bottom: 8px;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition);
    }

    img {
      max-width: 100%;
      display: block;
      height: auto;
    }

    button, .btn {
      cursor: pointer;
      font-family: "Inter", "SF Pro Display", "PingFang SC", sans-serif;
      font-weight: 500;
      border: none;
      transition: all var(--transition);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 6px;
    }

    .btn-primary {
      background-color: var(--accent-red);
      color: var(--white);
      padding: 14px 36px;
      border-radius: var(--radius-sm);
      font-size: 16px;
      box-shadow: 0 4px 10px rgba(199,62,58,0.2);
    }

    .btn-primary:hover {
      background-color: var(--accent-red-hover);
      transform: scale(1.03);
      box-shadow: 0 8px 16px rgba(199,62,58,0.3);
    }

    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--accent-red);
      color: var(--accent-red);
      padding: 14px 36px;
      border-radius: var(--radius-sm);
      font-size: 16px;
    }

    .btn-outline:hover {
      background-color: #FDF0EF;
      border-color: var(--accent-red-hover);
      color: var(--accent-red-hover);
    }

    /* 导航桌面 */
    .desktop-nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height-desktop);
      background: rgba(26,26,26,0.92);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      z-index: 1000;
      display: flex;
      align-items: center;
      border-bottom: 1px solid rgba(255,255,255,0.06);
    }

    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }

    .logo {
      font-size: 22px;
      font-weight: 700;
      color: var(--white);
      letter-spacing: 1px;
      display: flex;
      align-items: center;
      gap: 8px;
    }

    .logo-icon {
      width: 32px;
      height: 32px;
      background: var(--accent-gold);
      border-radius: 4px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: #1A1A1A;
      font-weight: 700;
      font-size: 18px;
    }

    .nav-links {
      display: flex;
      gap: 40px;
      list-style: none;
    }

    .nav-links a {
      color: #CCCCCC;
      font-weight: 500;
      font-size: 15px;
      position: relative;
      padding: 8px 0;
    }

    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent-gold);
      transition: width var(--transition);
    }

    .nav-links a:hover {
      color: var(--white);
    }

    .nav-links a:hover::after {
      width: 100%;
    }

    .nav-cta {
      background: var(--accent-red);
      color: white;
      padding: 10px 24px;
      border-radius: var(--radius-sm);
      font-size: 14px;
      font-weight: 600;
    }

    .nav-cta:hover {
      background: var(--accent-red-hover);
      transform: translateY(-1px);
    }

    /* 移动端汉堡 */
    .hamburger {
      display: none;
      background: none;
      border: none;
      color: white;
      font-size: 28px;
      cursor: pointer;
    }

    .mobile-menu-overlay {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: rgba(18,18,18,0.97);
      backdrop-filter: blur(12px);
      z-index: 999;
      display: none;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      gap: 32px;
    }

    .mobile-menu-overlay.active {
      display: flex;
    }

    .mobile-menu-overlay a {
      color: white;
      font-size: 24px;
      font-weight: 600;
    }

    .close-menu {
      position: absolute;
      top: 24px;
      right: 24px;
      background: none;
      border: none;
      color: white;
      font-size: 32px;
      cursor: pointer;
    }

    /* 底部移动Tab */
    .mobile-tab-bar {
      display: none;
      position: fixed;
      bottom: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height-mobile);
      background: var(--white);
      border-top: 1px solid var(--card-border);
      z-index: 1000;
      justify-content: space-around;
      align-items: center;
      padding: 0 8px;
      box-shadow: 0 -2px 12px rgba(0,0,0,0.03);
    }

    .tab-item {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 4px;
      color: #999;
      font-size: 11px;
      font-weight: 500;
    }

    .tab-item i {
      font-size: 20px;
      color: #999;
    }

    .tab-item.active i, .tab-item.active span {
      color: var(--accent-red);
    }

    /* Hero */
    .hero-section {
      background-color: var(--primary-charcoal);
      background-image: radial-gradient(circle at 20% 30%, rgba(212,175,55,0.05) 0%, transparent 35%);
      min-height: 90vh;
      display: flex;
      align-items: center;
      padding-top: var(--nav-height-desktop);
      position: relative;
      overflow: hidden;
    }

    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
    }

    .hero-left {
      flex: 0 0 55%;
    }

    .hero-right {
      flex: 0 0 45%;
      position: relative;
    }

    .hero-right img {
      width: 100%;
      height: auto;
      border-radius: 12px;
      transform: perspective(800px) rotateY(-5deg);
      box-shadow: 24px 24px 40px rgba(0,0,0,0.6);
      border: 1px solid rgba(255,255,255,0.1);
      object-fit: cover;
      aspect-ratio: 4/3;
    }

    .hero-sub {
      font-size: 18px;
      color: #B0B0B0;
      margin: 20px 0 32px;
      max-width: 480px;
    }

    .hero-actions {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }

    /* 板块通用 */
    .section {
      padding: 100px 0;
    }

    .section-dark {
      background-color: var(--bg-dark);
      color: var(--white);
    }

    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }

    .section-title h2 {
      position: relative;
      display: inline-block;
    }

    .section-title h2::after {
      content: '';
      position: absolute;
      bottom: -12px;
      left: 50%;
      transform: translateX(-50%);
      width: 60px;
      height: 2px;
      background: var(--accent-gold);
    }

    /* 亮点网格 */
    .strength-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }

    .strength-card {
      background: var(--card-bg);
      padding: 32px 28px;
      border-radius: var(--radius-sm);
      border: 1px solid var(--card-border);
      box-shadow: var(--shadow-light);
      transition: all var(--transition);
    }

    .strength-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
      border-color: var(--accent-gold);
    }

    .strength-icon {
      font-size: 36px;
      color: var(--accent-red);
      margin-bottom: 16px;
    }

    /* 案例瀑布 */
    .case-columns {
      columns: 2;
      column-gap: 28px;
    }

    .case-card {
      break-inside: avoid;
      background: var(--card-bg);
      border-radius: var(--radius-sm);
      overflow: hidden;
      margin-bottom: 28px;
      border: 1px solid var(--card-border);
      transition: all var(--transition);
      box-shadow: var(--shadow-light);
    }

    .case-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }

    .case-img {
      height: 220px;
      overflow: hidden;
    }

    .case-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.3s ease;
    }

    .case-card:hover .case-img img {
      transform: scale(1.05);
    }

    .case-info {
      padding: 20px;
    }

    .case-tag {
      color: var(--accent-red);
      font-size: 13px;
      font-weight: 600;
      margin-bottom: 8px;
    }

    /* 对比 */
    .compare-dual {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 28px;
    }

    .compare-card {
      background: var(--card-bg);
      padding: 40px 28px;
      border-radius: var(--radius-sm);
      border: 1px solid var(--card-border);
    }

    .compare-card.left {
      background: #F2F0EC;
      border-left: 4px solid #AAAAAA;
    }

    .compare-card.right {
      background: var(--white);
      border-left: 4px solid var(--accent-gold);
    }

    /* FAQ */
    .faq-list {
      max-width: 760px;
      margin: 0 auto;
    }

    .faq-item {
      border-bottom: 1px solid var(--card-border);
    }

    .faq-question {
      width: 100%;
      background: none;
      border: none;
      padding: 18px 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 700;
      font-size: 17px;
      color: var(--primary-charcoal);
      cursor: pointer;
    }

    .faq-icon {
      transition: transform 0.25s ease;
      font-size: 20px;
      color: var(--accent-red);
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-body);
      padding-right: 40px;
    }

    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }

    .faq-item.open .faq-icon {
      transform: rotate(45deg);
    }

    /* CTA尾板 */
    .cta-footer-board {
      background: var(--primary-charcoal);
      padding: 80px 0;
      text-align: center;
    }

    /* 页脚 */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      padding: 60px 0 40px;
    }

    .footer-col h4 {
      color: white;
      margin-bottom: 16px;
      font-weight: 600;
    }

    .footer-col p, .footer-col a {
      color: var(--text-footer);
      font-size: 14px;
      display: block;
      margin-bottom: 8px;
    }

    .footer-col a:hover {
      color: var(--accent-gold);
    }

    .copyright {
      border-top: 1px solid #333;
      padding: 24px 0;
      text-align: center;
      color: var(--text-footer);
      font-size: 13px;
    }

    /* 响应式 */
    @media (max-width: 1024px) {
      .hero-grid {
        flex-direction: column;
      }
      .hero-left, .hero-right {
        flex: auto;
        width: 100%;
      }
      .case-columns {
        columns: 2;
      }
    }

    @media (max-width: 768px) {
      .desktop-nav .nav-links, .desktop-nav .nav-cta {
        display: none;
      }
      .hamburger {
        display: block;
      }
      .mobile-tab-bar {
        display: flex;
      }
      body {
        padding-bottom: 70px;
      }
      h1 {
        font-size: 36px;
      }
      h2 {
        font-size: 28px;
      }
      .section {
        padding: 60px 0;
      }
      .strength-grid {
        grid-template-columns: 1fr;
      }
      .case-columns {
        columns: 1;
      }
      .compare-dual {
        grid-template-columns: 1fr;
      }
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
      .hero-right img {
        transform: none;
      }
    }

    @media (max-width: 480px) {
      h1 {
        font-size: 32px;
      }
      .btn-primary, .btn-outline {
        width: 100%;
        justify-content: center;
      }
    }