/* roulang page: index */
:root {
      --primary: #00F0FF;
      --secondary: #A855F7;
      --bg-deep: #0A0E17;
      --bg-footer: #060A10;
      --surface: rgba(255,255,255,0.04);
      --border-light: rgba(255,255,255,0.08);
      --text-title: #FFFFFF;
      --text-body: #B0C0D0;
      --text-highlight: #00F0FF;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', sans-serif;
      --font-mono: 'Inter', 'SF Pro Display', sans-serif;
      --radius-lg: 16px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.3);
      --shadow-glow: 0 8px 40px rgba(0,240,255,0.15);
      --transition: all 0.25s ease;
      --sidebar-width: 72px;
      --sidebar-expand: 240px;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-deep);
      color: var(--text-body);
      line-height: 1.6;
      overflow-x: hidden;
      display: flex;
      min-height: 100vh;
    }

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

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

    /* 主内容区偏移 */
    .main-content {
      margin-left: var(--sidebar-width);
      width: calc(100% - var(--sidebar-width));
      transition: margin-left 0.3s ease, width 0.3s ease;
    }

    /* ---------- 左侧导航 App Shell ---------- */
    .app-sidebar {
      position: fixed;
      top: 0;
      left: 0;
      height: 100vh;
      width: var(--sidebar-width);
      background: rgba(10, 14, 23, 0.85);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-right: 1px solid var(--border-light);
      display: flex;
      flex-direction: column;
      align-items: center;
      padding: 1.5rem 0;
      z-index: 100;
      transition: width 0.3s ease, padding 0.3s ease;
      overflow: hidden;
      white-space: nowrap;
    }

    .app-sidebar:hover {
      width: var(--sidebar-expand);
      padding-left: 1rem;
      padding-right: 1rem;
      align-items: flex-start;
    }

    .sidebar-logo {
      display: flex;
      align-items: center;
      gap: 0.75rem;
      margin-bottom: 2.5rem;
      padding-left: 0.5rem;
      width: 100%;
    }

    .logo-icon {
      font-size: 2rem;
      color: var(--primary);
      min-width: 2rem;
      text-align: center;
    }

    .logo-text {
      font-weight: 700;
      font-size: 1.2rem;
      color: var(--text-title);
      opacity: 0;
      transition: opacity 0.3s ease;
      white-space: nowrap;
    }

    .app-sidebar:hover .logo-text {
      opacity: 1;
    }

    .nav-menu {
      list-style: none;
      width: 100%;
      display: flex;
      flex-direction: column;
      gap: 0.5rem;
    }

    .nav-item a {
      display: flex;
      align-items: center;
      gap: 1rem;
      padding: 0.8rem 0.75rem;
      border-radius: var(--radius-md);
      color: var(--text-body);
      transition: var(--transition);
      white-space: nowrap;
    }

    .nav-item a i {
      font-size: 1.4rem;
      min-width: 1.5rem;
      text-align: center;
      color: var(--text-body);
      transition: var(--transition);
    }

    .nav-item a span {
      opacity: 0;
      transition: opacity 0.3s ease;
      font-weight: 500;
    }

    .app-sidebar:hover .nav-item a span {
      opacity: 1;
    }

    .nav-item a:hover,
    .nav-item a.active {
      background: rgba(0, 240, 255, 0.1);
      color: var(--primary);
    }

    .nav-item a:hover i,
    .nav-item a.active i {
      color: var(--primary);
    }

    .sidebar-social {
      margin-top: auto;
      display: flex;
      flex-direction: column;
      gap: 1rem;
      width: 100%;
      align-items: center;
      padding-bottom: 1rem;
    }

    .app-sidebar:hover .sidebar-social {
      flex-direction: row;
      justify-content: flex-start;
      padding-left: 0.75rem;
    }

    .sidebar-social a {
      font-size: 1.3rem;
      color: var(--text-body);
      transition: var(--transition);
    }

    .sidebar-social a:hover {
      color: var(--primary);
    }

    /* 移动端顶部导航 */
    .mobile-header {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 56px;
      background: rgba(10, 14, 23, 0.9);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border-bottom: 1px solid var(--border-light);
      z-index: 99;
      align-items: center;
      justify-content: space-between;
      padding: 0 1.2rem;
    }

    .mobile-logo {
      font-weight: 700;
      font-size: 1.2rem;
      color: var(--text-title);
      display: flex;
      align-items: center;
      gap: 0.5rem;
    }

    .hamburger {
      font-size: 1.6rem;
      color: var(--text-body);
      background: none;
      border: none;
      cursor: pointer;
    }

    .mobile-drawer {
      position: fixed;
      top: 56px;
      left: 0;
      width: 100%;
      background: rgba(10, 14, 23, 0.95);
      backdrop-filter: blur(25px);
      -webkit-backdrop-filter: blur(25px);
      border-bottom: 1px solid var(--border-light);
      padding: 1.5rem;
      display: none;
      flex-direction: column;
      gap: 1rem;
      z-index: 98;
      transform: translateY(-10px);
      opacity: 0;
      transition: 0.25s ease;
    }

    .mobile-drawer.open {
      display: flex;
      transform: translateY(0);
      opacity: 1;
    }

    .mobile-drawer a {
      color: var(--text-body);
      font-size: 1.1rem;
      padding: 0.5rem 0;
      border-bottom: 1px solid var(--border-light);
    }

    /* 容器与区块 */
    .section {
      padding: 120px 0;
    }

    .container-custom {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 2rem;
    }

    h1, h2, h3 {
      color: var(--text-title);
    }

    h1 {
      font-size: clamp(3rem, 6vw, 5rem);
      font-weight: 800;
      letter-spacing: -0.02em;
    }

    h2 {
      font-size: clamp(2rem, 4vw, 3rem);
      font-weight: 700;
      margin-bottom: 1rem;
    }

    .section-title {
      text-align: center;
      margin-bottom: 3rem;
    }

    .btn {
      display: inline-block;
      padding: 0.85rem 2.2rem;
      border-radius: var(--radius-sm);
      font-weight: 600;
      transition: var(--transition);
      cursor: pointer;
      border: none;
      font-size: 1rem;
    }

    .btn-primary {
      background: var(--primary);
      color: var(--bg-deep);
    }

    .btn-primary:hover {
      box-shadow: 0 0 30px rgba(0,240,255,0.6), 0 0 60px rgba(0,240,255,0.3);
      transform: translateY(-2px);
    }

    .btn-secondary {
      background: transparent;
      border: 1px solid var(--primary);
      color: var(--primary);
    }

    .btn-secondary:hover {
      background: rgba(0,240,255,0.1);
    }

    /* Hero */
    .hero {
      height: 100vh;
      display: flex;
      align-items: center;
      position: relative;
      overflow: hidden;
    }

    #particle-canvas {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      z-index: 0;
    }

    .hero-content {
      position: relative;
      z-index: 2;
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }

    .hero-left {
      max-width: 600px;
    }

    .hero-left h1 {
      margin-bottom: 1.5rem;
    }

    .hero-sub {
      font-size: 1.25rem;
      color: var(--text-body);
      margin-bottom: 2rem;
    }

    .hero-buttons {
      display: flex;
      gap: 1rem;
      flex-wrap: wrap;
    }

    .hero-card-mock {
      width: 380px;
      background: rgba(255,255,255,0.05);
      backdrop-filter: blur(18px);
      -webkit-backdrop-filter: blur(18px);
      border-radius: var(--radius-lg);
      border: 1px solid var(--border-light);
      padding: 1.5rem;
      box-shadow: var(--shadow-card);
    }

    .scroll-indicator {
      position: absolute;
      bottom: 2rem;
      left: 50%;
      transform: translateX(-50%);
      color: var(--primary);
      font-size: 2rem;
      animation: pulse 1.8s infinite;
      z-index: 2;
    }

    @keyframes pulse {
      0% { opacity: 0.5; transform: translateX(-50%) translateY(0); }
      50% { opacity: 1; transform: translateX(-50%) translateY(8px); }
      100% { opacity: 0.5; transform: translateX(-50%) translateY(0); }
    }

    /* 优势 1+2 布局 */
    .features-grid {
      display: grid;
      grid-template-columns: 1.5fr 1fr;
      gap: 1.5rem;
    }

    .feature-large {
      background: var(--surface);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-lg);
      padding: 2.5rem;
      border-left: 4px solid var(--primary);
    }

    .feature-small-group {
      display: flex;
      flex-direction: column;
      gap: 1.5rem;
    }

    .feature-card {
      background: var(--surface);
      backdrop-filter: blur(20px);
      -webkit-backdrop-filter: blur(20px);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      padding: 1.8rem;
    }

    .icon-box {
      width: 48px;
      height: 48px;
      background: rgba(0,240,255,0.1);
      border-radius: var(--radius-sm);
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 1rem;
    }

    /* 服务网格 2x2 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 1.8rem;
    }

    .service-card {
      background: var(--surface);
      backdrop-filter: blur(18px);
      -webkit-backdrop-filter: blur(18px);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-lg);
      padding: 2rem;
      transition: var(--transition);
    }

    .service-card:hover {
      transform: translateY(-8px);
      box-shadow: var(--shadow-glow);
      border-color: var(--primary);
    }

    .service-icon {
      width: 60px;
      height: 60px;
      background: linear-gradient(135deg, var(--secondary), var(--primary));
      border-radius: var(--radius-md);
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 1.2rem;
      transition: transform 0.3s;
    }

    .service-card:hover .service-icon {
      transform: scale(1.1) rotate(3deg);
    }

    /* 数据背书 */
    .stats-grid {
      display: flex;
      justify-content: space-around;
      flex-wrap: wrap;
      gap: 2rem;
      background: linear-gradient(180deg, rgba(0,240,255,0.05) 0%, transparent 100%);
      padding: 3rem 2rem;
      border-radius: var(--radius-lg);
    }

    .stat-item {
      text-align: center;
    }

    .stat-number {
      font-family: var(--font-mono);
      font-size: 3rem;
      font-weight: 700;
      color: var(--primary);
    }

    /* 案例左右交替 */
    .case-row {
      display: flex;
      align-items: center;
      gap: 3rem;
      margin-bottom: 4rem;
    }

    .case-row.reverse {
      flex-direction: row-reverse;
    }

    .case-text {
      flex: 1;
    }

    .case-img {
      flex: 1;
      background: rgba(255,255,255,0.04);
      backdrop-filter: blur(16px);
      border-radius: var(--radius-lg);
      padding: 1rem;
      transform: rotate(1deg);
      box-shadow: var(--shadow-card);
    }

    /* FAQ */
    .accordion {
      max-width: 800px;
      margin: 0 auto;
    }

    .accordion-item {
      background: rgba(255,255,255,0.03);
      backdrop-filter: blur(16px);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      margin-bottom: 1rem;
      overflow: hidden;
    }

    .accordion-header {
      padding: 1.2rem 1.5rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      font-weight: 600;
      color: #fff;
    }

    .accordion-icon {
      transition: transform 0.35s;
    }

    .accordion-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease;
      padding: 0 1.5rem;
      color: var(--text-body);
    }

    .accordion-item.active .accordion-content {
      max-height: 200px;
      padding-bottom: 1.5rem;
    }

    .accordion-item.active .accordion-icon {
      transform: rotate(45deg);
    }

    /* CTA */
    .cta-section {
      background: var(--bg-deep);
      text-align: center;
    }

    /* 页脚 */
    .footer {
      background: var(--bg-footer);
      border-top: 1px solid transparent;
      background-image: linear-gradient(to right, rgba(0,240,255,0) 0%, rgba(0,240,255,0.3) 50%, rgba(0,240,255,0) 100%);
      background-size: 100% 1px;
      background-repeat: no-repeat;
      background-position: top;
      padding-top: 3rem;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 2rem;
    }

    .footer a:hover {
      color: var(--primary);
    }

    @media (max-width: 1024px) {
      .main-content {
        margin-left: 0;
        width: 100%;
      }
      .app-sidebar {
        display: none;
      }
      .mobile-header {
        display: flex;
      }
      .section {
        padding: 80px 0;
      }
      .hero-content {
        flex-direction: column;
        text-align: center;
      }
      .hero-card-mock {
        width: 90%;
        margin-top: 2rem;
      }
      .features-grid {
        grid-template-columns: 1fr;
      }
      .services-grid {
        grid-template-columns: 1fr;
      }
      .case-row, .case-row.reverse {
        flex-direction: column;
      }
    }

    @media (max-width: 640px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
      .stats-grid {
        flex-direction: column;
        align-items: center;
      }
    }