/* roulang page: index */
:root {
      --primary-black: #0D0F12;
      --accent-orange: #FF6A00;
      --secondary-blue: #1E3A5F;
      --bg-light: #F8F9FA;
      --card-white: #FFFFFF;
      --text-main: #1A1A1A;
      --text-secondary: #5C5C5C;
      --text-on-dark: #FFFFFF;
      --text-on-dark-secondary: #CCCCCC;
      --border-light: #E8ECF1;
      --border-blue: rgba(30, 58, 95, 0.1);
      --gradient-button: linear-gradient(135deg, #FF6A00 0%, #FF8C3A 100%);
      --radius-card: 12px;
      --radius-button: 8px;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-card-hover: 0 8px 30px rgba(0,0,0,0.08);
      --shadow-button-hover: 0 8px 24px rgba(255,106,0,0.3);
      --transition-base: all 0.25s ease;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", system-ui, sans-serif;
      background-color: var(--bg-light);
      color: var(--text-main);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition-base);
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      outline: none;
      transition: var(--transition-base);
    }
    .btn {
      display: inline-block;
      padding: 14px 32px;
      border-radius: var(--radius-button);
      font-weight: 600;
      font-size: 16px;
      text-align: center;
    }
    .btn-primary {
      background: var(--gradient-button);
      color: var(--text-on-dark);
      box-shadow: 0 4px 12px rgba(255,106,0,0.2);
    }
    .btn-primary:hover {
      transform: translateY(-2px);
      box-shadow: var(--shadow-button-hover);
      color: white;
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--secondary-blue);
      color: var(--secondary-blue);
      padding: 12px 32px;
    }
    .btn-outline:hover {
      background: var(--secondary-blue);
      color: var(--text-on-dark);
      transform: translateY(-2px);
    }
    .section-title {
      font-size: 36px;
      font-weight: 600;
      line-height: 1.3;
      margin-bottom: 16px;
    }
    .section-desc {
      font-size: 16px;
      color: var(--text-secondary);
      margin-bottom: 40px;
    }
    header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid var(--border-light);
      z-index: 1000;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: 1280px;
      padding: 0 24px;
    }
    .logo {
      font-size: 22px;
      font-weight: 700;
      color: var(--accent-orange);
      letter-spacing: -0.5px;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      list-style: none;
    }
    .nav-links a {
      font-size: 15px;
      color: var(--text-main);
      font-weight: 500;
      padding: 8px 0;
      position: relative;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent-orange);
      transition: width 0.2s ease;
    }
    .nav-links a:hover {
      color: var(--accent-orange);
    }
    .nav-links a:hover::after {
      width: 100%;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: transparent;
      border: none;
      padding: 4px;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--accent-orange);
      display: block;
      border-radius: 2px;
    }
    .mobile-menu {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: var(--primary-black);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 32px;
      transform: translateX(100%);
      transition: transform 0.3s ease;
      z-index: 999;
    }
    .mobile-menu.active {
      transform: translateX(0);
    }
    .mobile-menu a {
      color: white;
      font-size: 20px;
      font-weight: 500;
    }
    .mobile-close {
      position: absolute;
      top: 24px;
      right: 24px;
      background: transparent;
      border: none;
      color: white;
      font-size: 28px;
    }
    section {
      padding: 80px 0;
    }
    .hero {
      padding-top: 120px;
      display: flex;
      align-items: center;
    }
    .hero-grid {
      display: flex;
      gap: 48px;
      align-items: center;
    }
    .hero-left {
      flex: 1;
    }
    .hero-right {
      flex: 1;
      position: relative;
    }
    .hero-image {
      width: 100%;
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card-hover);
    }
    .hero-data-overlay {
      position: absolute;
      bottom: 20px;
      right: 20px;
      background: rgba(13,15,18,0.85);
      backdrop-filter: blur(8px);
      padding: 12px 18px;
      border-radius: 8px;
      color: white;
      font-size: 14px;
      display: flex;
      gap: 16px;
      border-left: 4px solid var(--accent-orange);
    }
    .h1-title {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      letter-spacing: -0.5px;
      margin-bottom: 16px;
    }
    .h2-sub {
      font-size: 24px;
      font-weight: 500;
      color: var(--text-secondary);
      margin-bottom: 20px;
    }
    .hero-desc {
      color: var(--text-secondary);
      margin-bottom: 32px;
      font-size: 16px;
    }
    .hero-cta {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
      margin-bottom: 32px;
    }
    .trust-bar {
      display: flex;
      gap: 24px;
      align-items: center;
      opacity: 0.7;
    }
    .trust-bar img {
      height: 28px;
      filter: grayscale(1);
      opacity: 0.6;
    }
    .highlights-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr;
      gap: 24px;
      margin-top: 32px;
    }
    .highlight-card {
      background: var(--card-white);
      border-radius: var(--radius-card);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      border: 1px solid var(--border-light);
      transition: var(--transition-base);
    }
    .highlight-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    .highlight-card.large {
      grid-column: span 1;
    }
    .icon-circle {
      width: 48px;
      height: 48px;
      background: rgba(255,106,0,0.1);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--accent-orange);
      font-size: 22px;
    }
    .card-title {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 12px;
    }
    .showcase-waterfall {
      column-count: 3;
      column-gap: 24px;
      margin-top: 24px;
    }
    .case-card {
      break-inside: avoid;
      margin-bottom: 24px;
      background: var(--card-white);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition-base);
      border: 1px solid var(--border-light);
    }
    .case-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    .case-card img {
      border-radius: 12px 12px 0 0;
      transition: transform 0.3s ease;
    }
    .case-card:hover img {
      transform: scale(1.03);
    }
    .case-content {
      padding: 20px;
    }
    .case-tag {
      display: inline-block;
      background: var(--border-blue);
      color: var(--secondary-blue);
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 13px;
      font-weight: 500;
      margin-bottom: 8px;
    }
    .compare-wrapper {
      display: flex;
      gap: 0;
      background: var(--card-white);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      margin-top: 32px;
    }
    .compare-col {
      flex: 1;
      padding: 40px;
    }
    .compare-col.left {
      background: #F4F5F7;
    }
    .compare-col.right {
      background: white;
      border-left: 2px solid var(--accent-orange);
    }
    .compare-title {
      font-size: 24px;
      font-weight: 600;
      margin-bottom: 24px;
    }
    .compare-list {
      list-style: none;
    }
    .compare-list li {
      margin-bottom: 16px;
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 16px 0;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      font-size: 20px;
      font-weight: 600;
      transition: color 0.2s;
    }
    .faq-question:hover {
      color: var(--accent-orange);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-secondary);
      padding-right: 32px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
    }
    .faq-item.active .faq-question {
      color: var(--accent-orange);
    }
    .cta-full {
      background: var(--primary-black);
      text-align: center;
      padding: 100px 0;
    }
    .cta-full h2 {
      color: white;
      font-size: 42px;
    }
    .cta-sub {
      color: rgba(255,255,255,0.6);
      font-size: 18px;
      margin-bottom: 32px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
      padding: 48px 0;
    }
    .footer-col p {
      color: var(--text-on-dark-secondary);
      font-size: 14px;
      margin-top: 12px;
    }
    .footer-col h4 {
      color: white;
      margin-bottom: 16px;
      font-weight: 600;
    }
    .footer-links {
      list-style: none;
    }
    .footer-links li {
      margin-bottom: 12px;
    }
    .footer-links a {
      color: var(--text-on-dark-secondary);
      font-size: 14px;
    }
    .footer-links a:hover {
      color: var(--accent-orange);
    }
    .social-icons {
      display: flex;
      gap: 16px;
    }
    .social-icons a {
      width: 40px;
      height: 40px;
      border: 1px solid var(--text-on-dark-secondary);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--text-on-dark-secondary);
      transition: var(--transition-base);
    }
    .social-icons a:hover {
      border-color: var(--accent-orange);
      color: var(--accent-orange);
      background: rgba(255,106,0,0.1);
    }
    .copyright {
      border-top: 1px solid rgba(255,255,255,0.1);
      padding: 24px 0;
      text-align: center;
      color: var(--text-on-dark-secondary);
      font-size: 14px;
    }
    @media (max-width: 1024px) {
      .highlights-grid {
        grid-template-columns: 1fr 1fr;
      }
      .showcase-waterfall {
        column-count: 2;
      }
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .hero-grid {
        flex-direction: column;
      }
      .hero-right {
        order: -1;
      }
      .h1-title {
        font-size: 36px;
      }
      .section-title {
        font-size: 28px;
      }
      .highlights-grid {
        grid-template-columns: 1fr;
      }
      .showcase-waterfall {
        column-count: 1;
      }
      .compare-wrapper {
        flex-direction: column;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
      section {
        padding: 48px 0;
      }
      .cta-full h2 {
        font-size: 30px;
      }
    }