/* roulang page: index */
:root {
      --black-ice: #0B1A2F;
      --aurora-cyan: #00E5CC;
      --glacier-white: #F4F9FF;
      --dawn-orange: #FF6B35;
      --ice-rock-gray: #B0C4DE;
      --text-dark: #2C3E50;
      --card-shadow: 0 4px 20px rgba(11, 26, 47, 0.06);
      --card-hover-shadow: 0 8px 30px rgba(11, 26, 47, 0.12);
      --border-radius-card: 12px;
      --border-radius-btn: 8px;
      --border-radius-tag: 6px;
      --font-heading: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --font-number: 'Inter', 'SF Pro Text', sans-serif;
      --transition-base: all 0.25s ease;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-heading);
      background-color: #FFFFFF;
      color: var(--text-dark);
      line-height: 1.6;
      font-weight: 400;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    .section-padding {
      padding: 88px 0;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition-base);
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      font-weight: 600;
      border-radius: var(--border-radius-btn);
      transition: var(--transition-base);
      padding: 12px 28px;
      font-size: 16px;
      line-height: 1.2;
    }
    input, textarea {
      font-family: inherit;
      font-size: 16px;
      border: 1px solid var(--ice-rock-gray);
      background-color: var(--glacier-white);
      border-radius: var(--border-radius-btn);
      padding: 14px 16px;
      width: 100%;
      transition: var(--transition-base);
      outline: none;
    }
    input:focus, textarea:focus {
      border-color: var(--aurora-cyan);
      box-shadow: 0 0 0 3px rgba(0, 229, 204, 0.1);
    }
    h1, h2, h3 {
      font-weight: 700;
      color: var(--black-ice);
    }
    .bg-dark {
      background-color: var(--black-ice);
    }
    .text-cyan {
      color: var(--aurora-cyan);
    }
    .text-orange {
      color: var(--dawn-orange);
    }
    .separator {
      width: 48px;
      height: 4px;
      background-color: var(--aurora-cyan);
      margin: 16px 0;
    }
    /* 导航 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      height: 72px;
      background: rgba(11, 26, 47, 0.85);
      backdrop-filter: blur(12px);
      display: flex;
      align-items: center;
      transition: background 0.3s;
    }
    .navbar.scrolled {
      background: var(--black-ice);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      font-size: 26px;
      font-weight: 700;
      color: var(--aurora-cyan);
      display: flex;
      align-items: center;
      gap: 8px;
      letter-spacing: 0.5px;
    }
    .logo svg {
      width: 30px;
      height: 30px;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      list-style: none;
    }
    .nav-links a {
      color: var(--glacier-white);
      font-weight: 500;
      position: relative;
      padding: 4px 0;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -2px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--aurora-cyan);
      transition: width 0.3s;
    }
    .nav-links a:hover::after {
      width: 100%;
    }
    .nav-links a:hover {
      color: var(--aurora-cyan);
    }
    .btn-primary-nav {
      background: var(--aurora-cyan);
      color: var(--black-ice);
      font-weight: 700;
      margin-left: 12px;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
    }
    .hamburger span {
      width: 25px;
      height: 3px;
      background: white;
      border-radius: 2px;
    }
    @media (max-width: 768px) {
      .nav-links, .btn-primary-nav.desktop-cta {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .mobile-menu {
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        background: rgba(11, 26, 47, 0.95);
        backdrop-filter: blur(10px);
        flex-direction: column;
        padding: 32px;
        gap: 24px;
        display: none;
      }
      .mobile-menu.active {
        display: flex;
      }
    }

    /* Hero */
    .hero {
      background: linear-gradient(135deg, #0B1A2F 0%, #1A2F45 100%);
      min-height: 85vh;
      display: flex;
      align-items: center;
      color: white;
      position: relative;
      overflow: hidden;
      padding-top: 72px;
    }
    .hero-bg-pattern {
      position: absolute;
      inset: 0;
      background-image: radial-gradient(circle at 30% 40%, rgba(0,229,204,0.08) 1px, transparent 1px);
      background-size: 40px 40px;
    }
    .hero-content {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 40px;
      position: relative;
      z-index: 2;
    }
    .hero-text {
      flex: 1;
    }
    .hero-text h1 {
      font-size: 46px;
      font-weight: 700;
      color: white;
      margin-bottom: 18px;
      letter-spacing: -0.5px;
    }
    .hero-text p {
      font-size: 18px;
      color: var(--ice-rock-gray);
      margin-bottom: 36px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--aurora-cyan);
      color: var(--black-ice);
      font-weight: 700;
    }
    .btn-primary:hover {
      background: #00C4AE;
      transform: translateY(-2px);
      box-shadow: 0 8px 16px rgba(0,229,204,0.3);
    }
    .btn-outline {
      border: 2px solid white;
      color: white;
      background: transparent;
    }
    .btn-outline:hover {
      background: rgba(255,255,255,0.1);
    }
    .hero-image {
      flex: 1;
      text-align: right;
    }
    .hero-image img {
      border-radius: 24px;
      box-shadow: 0 20px 40px rgba(0,0,0,0.3);
    }
    @media (max-width: 768px) {
      .hero-content {
        flex-direction: column;
        text-align: center;
      }
      .hero-text h1 {
        font-size: 32px;
      }
    }

    /* 卡片系统 */
    .card {
      background: #FFFFFF;
      border-radius: var(--border-radius-card);
      box-shadow: var(--card-shadow);
      padding: 32px;
      transition: var(--transition-base);
      height: 100%;
    }
    .card:hover {
      transform: translateY(-6px);
      box-shadow: var(--card-hover-shadow), 0 0 0 1px rgba(0,229,204,0.25);
    }
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 28px;
    }
    @media (max-width: 1024px) {
      .grid-3, .grid-4 {
        grid-template-columns: repeat(2, 1fr);
      }
    }
    @media (max-width: 640px) {
      .grid-3, .grid-4 {
        grid-template-columns: 1fr;
      }
    }

    .icon-box {
      width: 56px;
      height: 56px;
      background: rgba(0,229,204,0.1);
      border-radius: 12px;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
    }
    .counter {
      font-family: var(--font-number);
      font-size: 48px;
      font-weight: 700;
      color: var(--aurora-cyan);
    }
    .case-card img {
      border-radius: 12px 12px 0 0;
      height: 180px;
      object-fit: cover;
      width: 100%;
    }
    .faq-item {
      border-bottom: 1px solid var(--ice-rock-gray);
      padding: 16px 0;
    }
    .faq-question {
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
      font-size: 18px;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease;
      color: var(--ice-rock-gray);
    }
    .footer {
      background: var(--black-ice);
      color: var(--glacier-white);
    }