/* roulang page: index */
:root {
      --primary: #FF4D00;
      --primary-rgb: 255, 77, 0;
      --secondary: #1E1E1E;
      --surface: #F7F7F2;
      --accent: #CCFF00;
      --accent-rgb: 204, 255, 0;
      --white: #FFFFFF;
      --gray-10: rgba(30,30,30,0.1);
      --gray-60: rgba(30,30,30,0.6);
      --text-body: var(--secondary);
      --text-dim: #555555;
      --radius-card: 16px;
      --radius-btn: 40px;
      --radius-input: 8px;
      --radius-accordion: 12px;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.04);
      --shadow-hover: 0 12px 32px rgba(255,77,0,0.12);
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', system-ui, -apple-system, sans-serif;
      --transition: 0.2s ease;
      --container: 1280px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
      scroll-padding-top: 80px;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--surface);
      color: var(--text-body);
      line-height: 1.4;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    button, input, textarea {
      font-family: inherit;
      font-size: 16px;
      outline: none;
    }
    .container {
      width: 100%;
      max-width: var(--container);
      margin: 0 auto;
      padding: 0 24px;
    }
    @media (max-width: 768px) {
      .container {
        padding: 0 20px;
      }
    }

    /* Header / Navigation */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: var(--white);
      z-index: 100;
      display: flex;
      align-items: center;
      border-bottom: 1px solid var(--gray-10);
      backdrop-filter: blur(8px);
      background: rgba(255,255,255,0.96);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: var(--container);
      margin: 0 auto;
      padding: 0 24px;
    }
    .logo {
      font-weight: 900;
      font-size: 1.8rem;
      letter-spacing: -0.02em;
      color: var(--primary);
      white-space: nowrap;
    }
    .desktop-nav {
      display: flex;
      align-items: center;
      gap: 40px;
      font-weight: 500;
    }
    .desktop-nav a {
      font-size: 1rem;
      color: var(--secondary);
    }
    .nav-cta {
      background: var(--primary);
      color: var(--white) !important;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      box-shadow: 0 4px 12px rgba(var(--primary-rgb),0.25);
      margin-left: 16px;
    }
    .nav-cta:hover {
      background: var(--secondary);
      color: var(--white);
      border-left: 3px solid var(--accent);
    }
    .mobile-bottom-nav {
      display: none;
      position: fixed;
      bottom: 0;
      left: 0;
      width: 100%;
      z-index: 110;
    }
    @media (max-width: 768px) {
      .desktop-nav {
        display: none;
      }
      .mobile-bottom-nav {
        display: flex;
        justify-content: center;
      }
    }

    /* mobile nav capsule */
    .mobile-capsule {
      background: var(--secondary);
      backdrop-filter: blur(20px);
      margin: 0 16px 16px;
      border-radius: 24px;
      display: flex;
      align-items: center;
      justify-content: space-around;
      padding: 8px 4px;
      height: 64px;
      box-shadow: 0 10px 30px rgba(0,0,0,0.25);
    }
    .mobile-capsule a {
      color: var(--white);
      font-size: 12px;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 4px;
      opacity: 0.8;
      font-weight: 500;
    }
    .mobile-capsule a.active-link,
    .mobile-capsule a:hover {
      color: var(--primary);
      opacity: 1;
    }

    /* Hero */
    .hero-section {
      background: var(--secondary);
      padding: 140px 0 100px;
      margin-top: 72px;
      color: var(--white);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
    }
    .hero-title {
      font-size: 56px;
      font-weight: 900;
      line-height: 1.1;
      letter-spacing: -0.02em;
      margin-bottom: 24px;
      color: var(--white);
    }
    .hero-sub {
      font-size: 18px;
      line-height: 1.6;
      color: rgba(255,255,255,0.85);
      max-width: 520px;
      margin-bottom: 32px;
    }
    .hero-actions {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary);
      color: var(--white);
      font-weight: 700;
      padding: 16px 36px;
      border-radius: var(--radius-btn);
      border: none;
      cursor: pointer;
      transition: var(--transition);
      display: inline-block;
      text-align: center;
      font-size: 1rem;
    }
    .btn-primary:hover {
      background: var(--secondary);
      color: var(--white);
      border-left: 4px solid var(--accent);
      transform: translateY(-2px);
    }
    .btn-ghost {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--white);
      font-weight: 600;
      padding: 14px 34px;
      border-radius: var(--radius-btn);
      transition: var(--transition);
      background: rgba(255,77,0,0.08);
    }
    .btn-ghost:hover {
      background: var(--primary);
      border-color: var(--primary);
    }
    .hero-image {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      min-height: 400px;
      border-radius: 24px;
      position: relative;
      overflow: hidden;
    }
    .hero-image::after {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(135deg, rgba(30,30,30,0.5) 0%, rgba(30,30,30,0.2) 100%);
    }
    @media (max-width: 768px) {
      .hero-grid {
        grid-template-columns: 1fr;
        gap: 32px;
      }
      .hero-title {
        font-size: 36px;
      }
      .hero-image {
        min-height: 280px;
      }
    }

    section {
      padding: 100px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 60px 0;
      }
    }
    .bg-white { background: var(--white); }
    .bg-surface { background: var(--surface); }
    .bg-dark { background: var(--secondary); color: var(--white); }

    .section-title {
      font-size: 40px;
      font-weight: 800;
      letter-spacing: -0.02em;
      margin-bottom: 16px;
    }
    .section-lead {
      font-size: 18px;
      color: var(--text-dim);
      margin-bottom: 48px;
    }

    /* highlight grid */
    .highlight-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 24px;
    }
    .highlight-card {
      background: var(--surface);
      border-radius: var(--radius-card);
      padding: 40px 24px;
      text-align: center;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
      border: 1px solid transparent;
    }
    .highlight-card:hover {
      border-color: var(--primary);
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }
    .highlight-icon {
      font-size: 44px;
      color: var(--accent);
      margin-bottom: 16px;
    }
    .highlight-number {
      font-size: 48px;
      font-weight: 800;
      color: var(--accent);
      line-height: 1.2;
    }
    @media (max-width: 768px) {
      .highlight-grid {
        grid-template-columns: 1fr;
      }
      .section-title { font-size: 28px; }
    }

    /* advantages alternating */
    .adv-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
      align-items: center;
      margin-bottom: 80px;
    }
    .adv-text h3 { font-size: 32px; font-weight: 700; }
    .adv-img {
      background: url('/assets/images/coverpic/cover-1.webp') center/cover no-repeat;
      height: 340px;
      border-radius: var(--radius-card);
    }
    @media (max-width: 768px) {
      .adv-row {
        grid-template-columns: 1fr;
      }
      .adv-img { height: 240px; }
    }

    /* cases waterfall */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 24px;
    }
    .case-card {
      background: var(--white);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .case-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-6px);
    }
    .case-img {
      background: url('/assets/images/coverpic/cover-2.webp') center/cover;
      height: 200px;
    }
    .case-body {
      padding: 24px;
    }
    .case-tag {
      background: transparent;
      border: 1px solid var(--primary);
      color: var(--primary);
      font-size: 12px;
      border-radius: 20px;
      padding: 4px 12px;
      display: inline-block;
      margin-bottom: 12px;
    }
    @media (max-width: 768px) {
      .cases-grid { grid-template-columns: 1fr; }
    }

    /* solutions compare */
    .compare-table {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 32px;
    }
    .compare-col {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 40px;
      box-shadow: var(--shadow-card);
    }
    .compare-col.right {
      background: var(--secondary);
      color: white;
      border-left: 8px solid var(--primary);
    }

    /* FAQ */
    .faq-item {
      background: var(--surface);
      border-radius: var(--radius-accordion);
      margin-bottom: 12px;
      border: 1px solid var(--gray-10);
      overflow: hidden;
    }
    .faq-question {
      padding: 20px 24px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
    }
    .faq-answer {
      padding: 0 24px 20px;
      display: none;
    }
    .faq-item.open .faq-answer {
      display: block;
      border-left: 4px solid var(--primary);
    }

    /* contact */
    .contact-form input, .contact-form textarea {
      width: 100%;
      background: var(--surface);
      border: 1px solid var(--gray-10);
      border-radius: var(--radius-input);
      padding: 14px 16px;
      margin-bottom: 16px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
    }
    @media (max-width: 768px) {
      .footer-grid { grid-template-columns: 1fr; }
    }