/* roulang page: index */
:root {
      --bg-dark: #0F0F0F;
      --bg-card: #1A1A1A;
      --bg-footer: #0A0A0A;
      --cyan: #00F0FF;
      --cyan-hover: #00D4E0;
      --purple: #7B2FBE;
      --white: #F4F4F5;
      --gray: #B0B0B0;
      --accent-orange: #FF4D00;
      --radius: 12px;
      --radius-sm: 8px;
      --transition: 0.3s cubic-bezier(0.25, 0.1, 0.25, 1);
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --font-mono: 'Inter', 'SF Pro Display', sans-serif;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg-dark);
      color: var(--white);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
      width: 100%;
    }

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

    a {
      text-decoration: none;
      color: inherit;
    }

    button, .btn {
      cursor: pointer;
      border: none;
      background: none;
      font-family: inherit;
    }

    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      transition: background 0.3s, backdrop-filter 0.3s;
      background: transparent;
      backdrop-filter: blur(0px);
    }

    .header.scrolled {
      background: rgba(15, 15, 15, 0.95);
      backdrop-filter: blur(12px);
    }

    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }

    .logo {
      font-size: 28px;
      font-weight: 800;
      color: var(--white);
      letter-spacing: -0.02em;
      display: flex;
      align-items: baseline;
      gap: 2px;
    }

    .logo .dot {
      color: var(--cyan);
      font-size: 36px;
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }

    .nav-links a {
      font-size: 15px;
      font-weight: 500;
      color: var(--gray);
      transition: color 0.2s;
      padding: 8px 0;
    }

    .nav-links a:hover,
    .nav-links a.active {
      color: var(--cyan);
    }

    .nav-cta {
      background: var(--cyan);
      color: var(--bg-dark);
      padding: 10px 24px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 14px;
      transition: background 0.2s, box-shadow 0.2s;
    }

    .nav-cta:hover {
      background: var(--cyan-hover);
      box-shadow: 0 0 20px rgba(0, 240, 255, 0.4);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
    }

    .hamburger span {
      width: 26px;
      height: 2px;
      background: var(--white);
      transition: 0.2s;
    }

    .mobile-menu {
      display: none;
    }

    /* Hero */
    .hero {
      padding: 180px 0 120px;
      background: radial-gradient(circle at 30% 40%, rgba(123, 47, 190, 0.15) 0%, transparent 60%);
    }

    .hero .container {
      display: flex;
      align-items: center;
      gap: 60px;
    }

    .hero-text {
      flex: 1;
    }

    .hero-text h1 {
      font-size: 56px;
      font-weight: 800;
      letter-spacing: -0.02em;
      color: var(--white);
      line-height: 1.2;
      margin-bottom: 24px;
      animation: fadeInUp 0.8s ease-out;
    }

    .hero-text p {
      font-size: 18px;
      color: var(--gray);
      margin-bottom: 40px;
      line-height: 1.8;
    }

    .hero-buttons {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }

    .btn-primary {
      background: var(--cyan);
      color: #0F0F0F;
      font-weight: 600;
      padding: 14px 36px;
      border-radius: var(--radius-sm);
      transition: 0.2s;
      font-size: 16px;
    }

    .btn-primary:hover {
      background: var(--cyan-hover);
      box-shadow: 0 0 24px rgba(0, 240, 255, 0.4);
      transform: scale(1.03);
    }

    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--cyan);
      color: var(--cyan);
      padding: 14px 36px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      transition: 0.2s;
      font-size: 16px;
    }

    .btn-outline:hover {
      background: rgba(0, 240, 255, 0.08);
      border-color: var(--cyan);
    }

    .hero-image {
      flex: 1;
      position: relative;
    }

    .hero-image img {
      border-radius: var(--radius);
      box-shadow: 0 0 30px rgba(0, 240, 255, 0.1);
    }

    @keyframes fadeInUp {
      from { opacity: 0; transform: translateY(20px); }
      to { opacity: 1; transform: translateY(0); }
    }

    /* 通用区块 */
    section {
      padding: 100px 0;
    }

    .section-title {
      font-size: 40px;
      font-weight: 700;
      color: var(--white);
      margin-bottom: 16px;
      position: relative;
      display: inline-block;
    }

    .section-title::after {
      content: '';
      position: absolute;
      left: 0;
      bottom: -8px;
      width: 40px;
      height: 3px;
      background: var(--cyan);
    }

    .section-sub {
      color: var(--gray);
      font-size: 16px;
      margin-bottom: 48px;
    }

    /* 卡片网格 */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }

    .card {
      background: var(--bg-card);
      border: 1px solid rgba(0, 240, 255, 0.08);
      border-radius: var(--radius);
      padding: 32px;
      transition: var(--transition);
    }

    .card:hover {
      transform: translateY(-4px);
      box-shadow: 0 0 20px rgba(0, 240, 255, 0.15);
      border-color: rgba(0, 240, 255, 0.3);
    }

    .card-icon {
      font-size: 48px;
      color: var(--cyan);
      margin-bottom: 20px;
    }

    .card h3 {
      font-size: 22px;
      font-weight: 600;
      margin-bottom: 12px;
      color: var(--white);
    }

    .card p {
      color: var(--gray);
      font-size: 16px;
      line-height: 1.75;
    }

    .decor-line {
      width: 40px;
      height: 4px;
      background: linear-gradient(90deg, var(--purple), transparent);
      margin-top: 20px;
    }

    /* 数据 */
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      text-align: center;
    }

    .stat-number {
      font-family: var(--font-mono);
      font-size: 48px;
      font-weight: 800;
      color: var(--cyan);
      margin-bottom: 8px;
    }

    .stat-label {
      color: var(--gray);
      font-size: 14px;
      letter-spacing: 0.1em;
    }

    /* 案例 */
    .case-row {
      display: flex;
      flex-direction: column;
      gap: 32px;
    }

    .case-card {
      background: var(--bg-card);
      border: 1px solid rgba(0, 240, 255, 0.08);
      border-radius: var(--radius);
      display: flex;
      overflow: hidden;
      transition: var(--transition);
    }

    .case-card:hover {
      box-shadow: 0 0 20px rgba(0, 240, 255, 0.12);
      border-color: rgba(0, 240, 255, 0.2);
    }

    .case-img {
      width: 45%;
      object-fit: cover;
    }

    .case-content {
      padding: 32px;
      display: flex;
      flex-direction: column;
      justify-content: center;
    }

    .case-tag {
      background: var(--purple);
      color: white;
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 13px;
      display: inline-block;
      width: fit-content;
      margin-bottom: 12px;
    }

    .case-link {
      color: var(--cyan);
      font-weight: 600;
      margin-top: 16px;
      transition: 0.2s;
    }

    .case-link:hover {
      text-decoration: underline;
    }

    /* 流程 */
    .process-steps {
      display: flex;
      justify-content: space-between;
      position: relative;
    }

    .process-steps::before {
      content: '';
      position: absolute;
      top: 24px;
      left: 5%;
      width: 90%;
      height: 2px;
      background: repeating-linear-gradient(90deg, rgba(0,240,255,0.3) 0 8px, transparent 8px 16px);
      z-index: 0;
    }

    .step {
      text-align: center;
      z-index: 1;
      background: var(--bg-dark);
      padding: 0 16px;
    }

    .step-circle {
      width: 48px;
      height: 48px;
      background: var(--cyan);
      color: var(--bg-dark);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      font-weight: 700;
      font-size: 18px;
      margin: 0 auto 12px;
    }

    .step h4 {
      font-weight: 600;
      margin-bottom: 8px;
    }

    .step p {
      color: var(--gray);
      font-size: 14px;
    }

    /* FAQ */
    .faq-list {
      display: flex;
      flex-direction: column;
      gap: 12px;
    }

    .faq-item {
      background: var(--bg-card);
      border-radius: var(--radius-sm);
      overflow: hidden;
      border-left: 3px solid transparent;
      transition: 0.2s;
    }

    .faq-item.active {
      border-left-color: var(--cyan);
    }

    .faq-question {
      padding: 20px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      font-weight: 600;
    }

    .faq-arrow {
      transition: 0.3s;
      color: var(--gray);
    }

    .faq-item.active .faq-arrow {
      transform: rotate(180deg);
      color: var(--cyan);
    }

    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      background: var(--bg-dark);
      padding: 0 20px;
    }

    .faq-item.active .faq-answer {
      max-height: 200px;
      padding: 20px;
    }

    /* CTA */
    .cta-block {
      background: radial-gradient(ellipse at center, rgba(123,47,190,0.25) 0%, #0F0F0F 70%);
      padding: 80px 0;
      text-align: center;
    }

    /* 页脚 */
    .footer {
      background: var(--bg-footer);
      padding: 60px 0 30px;
      color: #666;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      margin-bottom: 40px;
    }

    .footer-logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--white);
      margin-bottom: 12px;
    }

    .footer a {
      color: #666;
      font-size: 14px;
      transition: 0.2s;
    }

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

    .copyright {
      border-top: 1px solid #222;
      padding-top: 24px;
      text-align: center;
      font-size: 13px;
    }

    @media (max-width: 1024px) {
      .hero .container {
        flex-direction: column;
      }
      .hero-text h1 {
        font-size: 48px;
      }
      .grid-3 {
        grid-template-columns: repeat(2, 1fr);
      }
      .stats-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }

    @media (max-width: 768px) {
      .nav-links {
        display: none;
      }
      .hamburger {
        display: flex;
      }
      .mobile-menu {
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        background: #0F0F0F;
        flex-direction: column;
        padding: 24px;
        gap: 16px;
      }
      .mobile-menu.open {
        display: flex;
      }
      .hero-text h1 {
        font-size: 36px;
      }
      .section-title {
        font-size: 32px;
      }
      .grid-3 {
        grid-template-columns: 1fr;
      }
      .case-card {
        flex-direction: column;
      }
      .case-img {
        width: 100%;
        height: 200px;
      }
      .process-steps {
        flex-direction: column;
        gap: 24px;
      }
      .process-steps::before {
        display: none;
      }
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }

    @media (max-width: 480px) {
      .hero-text h1 {
        font-size: 32px;
      }
      .btn-primary, .btn-outline {
        width: 100%;
        max-width: 320px;
        text-align: center;
      }
    }