/* roulang page: index */
:root {
      --primary-bg: #0B0C10;
      --card-bg: #12141C;
      --accent-cyan: #00E5FF;
      --gold: #FFB300;
      --text-primary: #E0E0E0;
      --text-secondary: #9E9E9E;
      --border-light: rgba(255, 255, 255, 0.08);
      --card-hover-shadow: 0 8px 40px rgba(0, 229, 255, 0.15);
      --transition: all 0.3s cubic-bezier(0.23, 1, 0.32, 1);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-mono: "SF Mono", "Consolas", "Monaco", monospace;
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--primary-bg);
      color: var(--text-primary);
      line-height: 1.75;
      overflow-x: hidden;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    .section {
      padding: 100px 0;
    }
    @media (max-width: 1024px) {
      .section {
        padding: 80px 0;
      }
    }
    @media (max-width: 768px) {
      .section {
        padding: 60px 0;
      }
    }
    /* 导航 */
    #nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 99;
      background: transparent;
      transition: background 0.3s, backdrop-filter 0.3s, box-shadow 0.3s;
    }
    #nav.scrolled {
      background: rgba(11, 12, 16, 0.92);
      backdrop-filter: blur(14px);
      box-shadow: 0 4px 20px rgba(0,0,0,0.5);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 18px 24px;
      max-width: 1280px;
      margin: 0 auto;
    }
    .logo {
      display: flex;
      align-items: center;
      font-weight: 700;
      font-size: 1.6rem;
      color: var(--accent-cyan);
      letter-spacing: 2px;
    }
    .logo svg {
      width: 28px;
      height: 28px;
      margin-right: 10px;
      fill: var(--gold);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 2.2rem;
      list-style: none;
      margin: 0;
      padding: 0;
    }
    .nav-links a {
      color: var(--text-primary);
      font-weight: 500;
      position: relative;
      padding: 6px 0;
      transition: color 0.2s;
    }
    .nav-links a::after {
      content: "";
      position: absolute;
      width: 0;
      height: 2px;
      bottom: 0;
      left: 50%;
      background: var(--accent-cyan);
      transition: width 0.25s ease, left 0.25s ease;
    }
    .nav-links a:hover {
      color: var(--accent-cyan);
    }
    .nav-links a:hover::after {
      width: 100%;
      left: 0;
    }
    .nav-cta-btn {
      background: var(--accent-cyan);
      color: #0B0C10;
      font-weight: 600;
      padding: 10px 26px;
      border-radius: var(--radius-btn);
      transition: var(--transition);
      margin-left: 1rem;
      font-size: 0.95rem;
      border: none;
      cursor: pointer;
    }
    .nav-cta-btn:hover {
      background: #33EAFF;
      transform: translateY(-2px);
      box-shadow: 0 0 18px rgba(0,229,255,0.6);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 6px;
      background: transparent;
      border: none;
      cursor: pointer;
    }
    .hamburger span {
      width: 28px;
      height: 2.5px;
      background: var(--text-primary);
      transition: var(--transition);
    }
    @media (max-width: 768px) {
      .nav-links {
        position: fixed;
        top: 0;
        right: -100%;
        width: 75%;
        max-width: 320px;
        height: 100vh;
        background: #0B0C10;
        flex-direction: column;
        justify-content: center;
        gap: 2.8rem;
        padding: 2rem;
        transition: right 0.4s ease;
        box-shadow: -8px 0 25px rgba(0,0,0,0.7);
        backdrop-filter: blur(20px);
      }
      .nav-links.active {
        right: 0;
      }
      .hamburger {
        display: flex;
        z-index: 1001;
      }
      .nav-cta-btn {
        margin-left: 0;
        margin-top: 10px;
      }
    }
    /* Hero */
    #hero {
      min-height: 100vh;
      background: linear-gradient(135deg, rgba(11,12,16,0.8) 10%, rgba(11,12,16,0.3) 80%), url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      display: flex;
      align-items: center;
      justify-content: center;
      text-align: center;
      position: relative;
      overflow: hidden;
      padding-top: 80px;
    }
    .hero-content {
      max-width: 860px;
      padding: 0 24px;
    }
    .hero-title {
      font-size: clamp(2.8rem, 8vw, 4.8rem);
      font-weight: 700;
      line-height: 1.2;
      margin-bottom: 1.2rem;
      letter-spacing: 2px;
      animation: fadeUp 0.9s ease;
    }
    .hero-sub {
      font-size: clamp(1.1rem, 2.5vw, 1.4rem);
      color: rgba(224,224,224,0.85);
      margin-bottom: 2.5rem;
    }
    .hero-btns {
      display: flex;
      gap: 20px;
      justify-content: center;
      flex-wrap: wrap;
      animation: fadeUp 1.2s ease;
    }
    .btn-primary, .btn-outline {
      padding: 15px 40px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 1rem;
      transition: var(--transition);
      display: inline-block;
      cursor: pointer;
    }
    .btn-primary {
      background: var(--accent-cyan);
      color: #0B0C10;
      border: none;
    }
    .btn-primary:hover {
      background: #33EAFF;
      box-shadow: 0 0 24px rgba(0,229,255,0.6);
      transform: translateY(-3px);
    }
    .btn-outline {
      background: transparent;
      border: 1px solid var(--accent-cyan);
      color: var(--accent-cyan);
    }
    .btn-outline:hover {
      background: rgba(0,229,255,0.08);
      transform: translateY(-3px);
    }
    @keyframes fadeUp {
      0% { opacity: 0; transform: translateY(24px); }
      100% { opacity: 1; transform: translateY(0); }
    }
    /* 优势 */
    .asymmetric-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
    }
    .big-card {
      background: rgba(255,255,255,0.03);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-card);
      padding: 24px;
      display: flex;
      flex-direction: column-reverse;
      backdrop-filter: blur(4px);
    }
    .small-cards {
      display: flex;
      flex-direction: column;
      gap: 24px;
    }
    .feature-item {
      background: rgba(255,255,255,0.03);
      border: 1px solid var(--border-light);
      border-radius: var(--radius-card);
      padding: 22px;
    }
    @media (min-width: 769px) {
      .big-card {
        flex-direction: row;
        align-items: center;
        gap: 24px;
      }
    }
    @media (max-width: 768px) {
      .asymmetric-grid {
        grid-template-columns: 1fr;
      }
    }
    /* 服务卡片 */
    .services-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 28px;
    }
    .service-card {
      background: rgba(255,255,255,0.02);
      border-radius: var(--radius-card);
      overflow: hidden;
      border: 1px solid rgba(255,255,255,0.05);
      transition: var(--transition);
    }
    .service-card:hover {
      transform: translateY(-8px);
      box-shadow: var(--card-hover-shadow);
    }
    .service-img {
      height: 210px;
      overflow: hidden;
    }
    .service-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.5s;
    }
    .service-card:hover .service-img img {
      transform: scale(1.06);
    }
    @media (max-width: 1024px) {
      .services-grid { grid-template-columns: repeat(2,1fr); }
    }
    @media (max-width: 520px) {
      .services-grid { grid-template-columns: 1fr; }
    }
    /* 数据带 */
    #stats {
      background: #0a0b10;
    }
    .stats-bar {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      text-align: center;
    }
    .stat-number {
      font-family: var(--font-mono);
      font-size: 2.8rem;
      font-weight: 700;
      color: var(--gold);
    }
    @media(max-width:768px){ .stats-bar{grid-template-columns:repeat(2,1fr); gap:24px;} }
    /* 案例 2x2 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(2,1fr);
      gap: 24px;
    }
    .case-card {
      position: relative;
      border-radius: var(--radius-card);
      overflow: hidden;
    }
    @media(max-width:768px){ .cases-grid{grid-template-columns:1fr;} }
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 18px 0;
    }
    .faq-question {
      font-weight: 600;
      display: flex;
      align-items: center;
      gap: 14px;
    }
    /* CTA 呼吸 */
    .breathing {
      animation: breath 2.4s infinite;
    }
    @keyframes breath {
      0%{box-shadow: 0 0 6px rgba(0,229,255,0.4);}
      50%{box-shadow:0 0 22px rgba(255,179,0,0.6), 0 0 15px #00e5ff;}
      100%{box-shadow:0 0 6px rgba(0,229,255,0.4);}
    }