/* roulang page: index */
:root {
      --primary: #0A0E27;
      --primary-light: #1A1F3A;
      --accent: #FF4D2E;
      --accent-hover: #E63E1F;
      --accent-soft: rgba(255, 77, 46, 0.08);
      --bg-body: #FAFAFA;
      --bg-light: #F5F5F5;
      --text-primary: #1E1E1E;
      --text-body: #333333;
      --text-weak: #666666;
      --text-footer: #CCCCCC;
      --white: #FFFFFF;
      --border-light: #E0E0E0;
      --shadow-sm: 0 4px 20px rgba(0,0,0,0.06);
      --shadow-md: 0 8px 30px rgba(0,0,0,0.12);
      --radius-card: 16px;
      --radius-btn: 10px;
      --radius-pill: 50px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
      --font-mono: "Inter", "Roboto", "SF Mono", monospace;
      --transition: 0.25s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--bg-body);
      color: var(--text-body);
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    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: inherit;
      border: none;
      outline: none;
      background: transparent;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: transparent;
      transition: background 0.3s, backdrop-filter 0.3s, box-shadow 0.3s;
    }
    .header.scrolled {
      background: rgba(10, 14, 39, 0.94);
      backdrop-filter: blur(12px);
      box-shadow: 0 4px 20px rgba(0,0,0,0.2);
    }
    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
      padding: 0 32px;
      max-width: 1300px;
      margin: 0 auto;
    }
    .logo {
      font-size: 1.8rem;
      font-weight: 700;
      color: var(--white);
      letter-spacing: 1px;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .logo i {
      font-size: 2rem;
      color: var(--accent);
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .nav-links a {
      color: rgba(255,255,255,0.85);
      font-weight: 500;
      font-size: 1rem;
      position: relative;
      padding: 6px 0;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent);
      transition: width 0.2s;
    }
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    .menu-toggle {
      display: none;
      background: none;
      color: white;
      font-size: 1.8rem;
      cursor: pointer;
      border: none;
    }
    .mobile-menu {
      position: fixed;
      top: 0;
      right: -100%;
      width: 280px;
      height: 100vh;
      background: var(--primary);
      padding: 80px 32px;
      display: flex;
      flex-direction: column;
      gap: 28px;
      transition: right 0.35s ease;
      z-index: 999;
      box-shadow: -5px 0 25px rgba(0,0,0,0.3);
    }
    .mobile-menu.active {
      right: 0;
    }
    .mobile-menu a {
      color: white;
      font-size: 1.3rem;
      font-weight: 500;
      border-bottom: 1px solid rgba(255,255,255,0.15);
      padding-bottom: 12px;
    }
    .overlay {
      position: fixed;
      inset: 0;
      background: rgba(0,0,0,0.6);
      z-index: 998;
      display: none;
    }
    .overlay.active {
      display: block;
    }
    /* Hero */
    .hero {
      min-height: 100vh;
      background: linear-gradient(135deg, #0A0E27 0%, #1A1F3A 100%);
      display: flex;
      align-items: center;
      position: relative;
      overflow: hidden;
      padding: 120px 0 80px;
    }
    .hero::before {
      content: '';
      position: absolute;
      inset: 0;
      background: url('/assets/images/backpic/hero-bg.webp') center/cover no-repeat;
      opacity: 0.18;
      z-index: 0;
    }
    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 750px;
    }
    .hero h1 {
      font-size: clamp(2.5rem, 6vw, 3.8rem);
      font-weight: 700;
      line-height: 1.2;
      color: white;
      margin-bottom: 24px;
      letter-spacing: -0.5px;
    }
    .hero .subtitle {
      font-size: 1.4rem;
      color: rgba(255,255,255,0.8);
      margin-bottom: 40px;
      max-width: 600px;
    }
    .btn-group {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--accent);
      color: white;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 1.1rem;
      display: inline-flex;
      align-items: center;
      gap: 8px;
      transition: 0.2s;
      border: 2px solid transparent;
      box-shadow: 0 8px 20px rgba(255,77,46,0.3);
    }
    .btn-primary:hover {
      background: var(--accent-hover);
      transform: scale(1.03);
      box-shadow: 0 12px 28px rgba(255,77,46,0.4);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid white;
      color: white;
      padding: 14px 36px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 1.1rem;
      transition: 0.2s;
    }
    .btn-outline:hover {
      background: white;
      color: var(--primary);
    }
    .scroll-indicator {
      position: absolute;
      bottom: 30px;
      right: 40px;
      color: rgba(255,255,255,0.5);
      font-size: 1.8rem;
      animation: bounce 2s infinite;
    }
    @keyframes bounce {
      0%,100%{transform:translateY(0);}
      50%{transform:translateY(-10px);}
    }
    /* 通用区块 */
    section {
      padding: 90px 0;
    }
    .section-title {
      font-size: 2.4rem;
      font-weight: 600;
      margin-bottom: 16px;
      color: var(--primary);
    }
    .section-desc {
      color: var(--text-weak);
      max-width: 650px;
      margin-bottom: 48px;
      font-size: 1.15rem;
    }
    /* 服务 2+1 错层 */
    #services {
      background: var(--white);
    }
    .services-grid {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 30px;
      max-width: 1000px;
      margin: 0 auto;
    }
    .service-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 32px 24px;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
      flex: 1 1 280px;
      max-width: 320px;
      text-align: left;
      position: relative;
    }
    .service-card:nth-child(3) {
      flex: 0 0 300px;
      margin-top: 20px;
    }
    .service-card:hover {
      transform: translateY(-8px);
      box-shadow: var(--shadow-md);
    }
    .icon-circle {
      width: 56px;
      height: 56px;
      background: var(--accent-soft);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 1.8rem;
      color: var(--accent);
      margin-bottom: 24px;
    }
    .service-card h3 {
      font-size: 1.5rem;
      font-weight: 600;
      margin-bottom: 12px;
    }
    .decor-line {
      width: 40px;
      height: 3px;
      background: var(--accent);
      margin-bottom: 16px;
    }
    .service-card p {
      color: var(--text-weak);
      margin-bottom: 20px;
    }
    .link-arrow {
      color: var(--accent);
      font-weight: 600;
      display: inline-flex;
      align-items: center;
      gap: 6px;
    }
    .link-arrow:hover {
      text-decoration: underline;
    }
    /* 数据条 */
    #advantages {
      background: var(--primary-light);
      color: white;
      padding: 70px 0;
    }
    .stats-track {
      display: flex;
      gap: 48px;
      overflow-x: auto;
      padding-bottom: 10px;
      scroll-snap-type: x mandatory;
      -webkit-overflow-scrolling: touch;
    }
    .stat-item {
      flex: 0 0 auto;
      min-width: 160px;
      scroll-snap-align: start;
      text-align: center;
    }
    .stat-number {
      font-size: 3.2rem;
      font-weight: 700;
      color: var(--accent);
      font-family: var(--font-mono);
    }
    .stat-label {
      font-size: 0.95rem;
      opacity: 0.8;
      margin-top: 8px;
    }
    /* 案例瀑布流 */
    #cases {
      background: var(--bg-body);
    }
    .cases-masonry {
      columns: 3;
      column-gap: 24px;
    }
    .case-card {
      break-inside: avoid;
      background: white;
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      margin-bottom: 24px;
      transition: var(--transition);
    }
    .case-card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-md);
    }
    .case-img {
      height: 200px;
      background-color: #ddd;
      object-fit: cover;
      width: 100%;
    }
    .case-info {
      padding: 20px;
    }
    .badge {
      background: var(--accent-soft);
      color: var(--accent);
      padding: 4px 14px;
      border-radius: 20px;
      font-size: 0.8rem;
      font-weight: 600;
      display: inline-block;
      margin-bottom: 10px;
    }
    .case-info h4 {
      font-weight: 600;
      margin-bottom: 8px;
    }
    /* 解决方案交替 */
    .solution-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }
    .solution-row.reverse {
      flex-direction: row-reverse;
    }
    .solution-text {
      flex: 1;
    }
    .solution-img {
      flex: 1;
      background: #e0e0e0;
      border-radius: var(--radius-card);
      height: 280px;
      background-size: cover;
      background-position: center;
    }
    /* FAQ */
    #faq {
      background: var(--bg-light);
    }
    .accordion-item {
      border-bottom: 1px solid var(--border-light);
      background: white;
      border-radius: 14px;
      margin-bottom: 12px;
      overflow: hidden;
    }
    .accordion-btn {
      width: 100%;
      text-align: left;
      padding: 22px 24px;
      font-weight: 600;
      font-size: 1.1rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      background: white;
      cursor: pointer;
    }
    .accordion-btn i {
      transition: 0.25s;
      color: var(--accent);
    }
    .accordion-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      background: white;
      padding: 0 24px;
    }
    .accordion-content p {
      padding-bottom: 20px;
      color: var(--text-body);
    }
    .accordion-item.active .accordion-btn i {
      transform: rotate(45deg);
    }
    /* CTA 联系 */
    #contact {
      background: var(--primary);
      color: white;
    }
    .contact-grid {
      display: flex;
      gap: 50px;
      flex-wrap: wrap;
    }
    .contact-form {
      flex: 1.2;
    }
    .input-field {
      width: 100%;
      padding: 14px 0;
      background: transparent;
      border-bottom: 2px solid rgba(255,255,255,0.3);
      color: white;
      margin-bottom: 28px;
      transition: 0.2s;
    }
    .input-field:focus {
      border-bottom-color: var(--accent);
      box-shadow: 0 2px 8px rgba(255,77,46,0.3);
    }
    .contact-info {
      flex: 0.8;
      display: flex;
      flex-direction: column;
      gap: 24px;
      justify-content: center;
    }
    /* 页脚 */
    .footer {
      background: #0A0E27;
      color: var(--text-footer);
      padding: 60px 0 20px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      margin-bottom: 40px;
    }
    .footer a:hover {
      color: var(--accent);
    }
    .social-icons i {
      font-size: 1.5rem;
      margin-right: 18px;
      transition: 0.2s;
    }
    .social-icons i:hover {
      color: var(--accent);
    }
    @media (max-width: 992px) {
      .nav-links { display: none; }
      .menu-toggle { display: block; }
      .cases-masonry { columns: 2; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .solution-row, .solution-row.reverse { flex-direction: column; }
    }
    @media (max-width: 640px) {
      .nav { padding: 0 20px; }
      .cases-masonry { columns: 1; }
      .services-grid { flex-direction: column; align-items: center; }
      .service-card:nth-child(3) { margin-top: 0; }
      .footer-grid { grid-template-columns: 1fr; }
      .btn-group { flex-direction: column; align-items: flex-start; }
    }