/* roulang page: index */
:root {
      --primary-black: #0D0D0D;
      --deep-gray: #1A1A1A;
      --electric-violet: #7B2FFF;
      --amber-gold: #F5A623;
      --smoke-white: #F2F0EB;
      --cool-gray: #9A9A9A;
      --card-inset: inset 0 1px 0 rgba(255,255,255,0.03);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --radius-tag: 4px;
      --shadow-glow: 0 8px 32px rgba(123,47,255,0.25);
      --transition-smooth: 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
      --font-sans: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", sans-serif;
      --font-data: "Inter", "SF Pro Display", system-ui;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--primary-black);
      color: var(--smoke-white);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      scroll-behavior: smooth;
    }

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

    /* 导航 */
    .nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(13,13,13,0.92);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(123,47,255,0.25);
      z-index: 1000;
      transition: background 0.3s, box-shadow 0.3s;
    }
    .nav.scrolled {
      background: rgba(13,13,13,0.98);
      box-shadow: 0 4px 20px rgba(0,0,0,0.6);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 1.6rem;
      letter-spacing: -0.5px;
      color: var(--smoke-white);
      text-decoration: none;
    }
    .logo-icon {
      font-size: 2rem;
      color: var(--electric-violet);
      filter: drop-shadow(0 0 6px rgba(123,47,255,0.6));
    }
    .nav-menu {
      display: flex;
      gap: 2.5rem;
      list-style: none;
    }
    .nav-menu a {
      color: var(--cool-gray);
      text-decoration: none;
      font-weight: 500;
      font-size: 0.95rem;
      letter-spacing: 0.3px;
      transition: color 0.2s;
      position: relative;
      padding: 0.25rem 0;
    }
    .nav-menu a:hover,
    .nav-menu a.active {
      color: var(--smoke-white);
    }
    .nav-menu a::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 3px;
      background: var(--amber-gold);
      border-radius: 4px;
      transition: width 0.3s;
    }
    .nav-menu a:hover::after,
    .nav-menu a.active::after {
      width: 100%;
    }
    .nav-cta {
      background: var(--electric-violet);
      color: white;
      padding: 0.7rem 1.8rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      text-decoration: none;
      transition: background 0.3s, color 0.3s;
      border: none;
      cursor: pointer;
      letter-spacing: 0.5px;
    }
    .nav-cta:hover {
      background: var(--amber-gold);
      color: #0D0D0D;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
      cursor: pointer;
      padding: 8px;
    }
    .hamburger span {
      width: 26px;
      height: 2px;
      background: var(--smoke-white);
      transition: 0.3s;
    }
    @media (max-width: 768px) {
      .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        background: rgba(13,13,13,0.98);
        backdrop-filter: blur(20px);
        flex-direction: column;
        gap: 0;
        padding: 1.5rem 0;
        transform: translateY(-120%);
        opacity: 0;
        transition: 0.4s ease;
        border-bottom: 1px solid var(--electric-violet);
      }
      .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
      }
      .nav-menu li {
        padding: 1rem 2rem;
        border-left: 3px solid transparent;
      }
      .nav-menu li:hover {
        border-left-color: var(--amber-gold);
        background: rgba(123,47,255,0.05);
      }
      .hamburger {
        display: flex;
      }
    }

    /* 板块通用 */
    section {
      padding: 100px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 64px 0;
      }
    }
    h2 {
      font-size: 40px;
      font-weight: 700;
      margin-bottom: 2rem;
      letter-spacing: -0.5px;
    }
    @media (max-width: 480px) {
      h2 { font-size: 32px; }
    }

    /* Hero */
    #hero {
      padding-top: 140px;
      background: radial-gradient(circle at 30% 40%, rgba(123,47,255,0.15) 0%, transparent 60%);
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 3rem;
    }
    .hero-left {
      flex: 1 1 55%;
    }
    .hero-right {
      flex: 1 1 45%;
      position: relative;
    }
    .hero-right img {
      width: 100%;
      height: auto;
      border-radius: var(--radius-card);
      box-shadow: 0 20px 40px rgba(123,47,255,0.3);
      filter: brightness(0.9);
    }
    .hero-overlay {
      position: absolute;
      top: 0; left: 0; width: 100%; height: 100%;
      background: linear-gradient(135deg, rgba(123,47,255,0.25), rgba(245,166,35,0.2));
      border-radius: var(--radius-card);
    }
    h1 {
      font-size: 56px;
      font-weight: 700;
      line-height: 1.2;
      letter-spacing: -1%;
      margin-bottom: 1.2rem;
      color: white;
    }
    .hero-sub {
      font-size: 18px;
      color: var(--cool-gray);
      margin-bottom: 2rem;
      max-width: 80%;
    }
    .hero-actions {
      display: flex;
      gap: 1.2rem;
      margin-bottom: 2.5rem;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--electric-violet);
      color: white;
      padding: 0.9rem 2.2rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      text-decoration: none;
      display: inline-block;
      transition: background 0.3s, color 0.3s;
      border: none;
      cursor: pointer;
    }
    .btn-primary:hover {
      background: var(--amber-gold);
      color: #0D0D0D;
    }
    .btn-outline {
      background: transparent;
      border: 1px solid var(--amber-gold);
      color: var(--amber-gold);
      padding: 0.9rem 2.2rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      text-decoration: none;
      transition: 0.3s;
    }
    .btn-outline:hover {
      background: var(--amber-gold);
      color: #0D0D0D;
    }
    .trust-signals {
      display: flex;
      gap: 2rem;
      color: var(--cool-gray);
      font-size: 0.9rem;
    }
    @media (max-width: 768px) {
      .hero-grid {
        flex-direction: column;
      }
      .hero-right {
        order: -1;
        margin-bottom: 2rem;
      }
      h1 { font-size: 40px; }
    }

    /* 亮点网格 */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 24px;
    }
    .highlight-card {
      background: var(--deep-gray);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--card-inset);
      border-top: 3px solid var(--electric-violet);
      transition: var(--transition-smooth);
    }
    .highlight-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-glow);
      border-top-color: var(--amber-gold);
    }
    .highlight-icon {
      font-size: 2.5rem;
      margin-bottom: 1rem;
      color: var(--amber-gold);
    }
    @media (max-width: 768px) {
      .grid-3 { grid-template-columns: 1fr; }
    }

    /* 服务卡片 */
    .services-grid {
      display: flex;
      gap: 24px;
      align-items: flex-start;
    }
    .service-card {
      background: var(--deep-gray);
      border-radius: var(--radius-card);
      flex: 1;
      overflow: hidden;
      transition: var(--transition-smooth);
      display: flex;
      flex-direction: column;
    }
    .service-card:nth-child(2) {
      margin-top: -20px;
    }
    .service-card img {
      width: 100%;
      height: 200px;
      object-fit: cover;
    }
    .service-text {
      padding: 28px;
    }
    .service-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-glow);
    }
    @media (max-width: 768px) {
      .services-grid {
        flex-direction: column;
      }
      .service-card:nth-child(2) {
        margin-top: 0;
      }
    }

    /* 案例瀑布 */
    .waterfall {
      display: grid;
      grid-template-columns: repeat(3,1fr);
      gap: 24px;
    }
    .case-card {
      background: var(--deep-gray);
      border-radius: var(--radius-card);
      overflow: hidden;
      transition: var(--transition-smooth);
    }
    .case-card img {
      width: 100%;
      height: 180px;
      object-fit: cover;
    }
    .case-info {
      padding: 20px;
    }
    .case-number {
      font-size: 2rem;
      font-weight: 700;
      color: var(--amber-gold);
      font-family: var(--font-data);
    }
    @media (max-width: 768px) {
      .waterfall { grid-template-columns: 1fr; }
    }

    /* 对比 */
    .compare-row {
      display: flex;
      gap: 2rem;
      align-items: center;
    }
    .compare-col {
      flex:1;
      background: var(--deep-gray);
      border-radius: var(--radius-card);
      padding: 2rem;
    }
    .vs {
      font-size: 2rem;
      font-weight: 700;
      color: var(--electric-violet);
      text-align: center;
    }
    @media (max-width: 768px) {
      .compare-row { flex-direction: column; }
      .vs { margin: 1rem 0; }
    }

    /* FAQ */
    .faq-item {
      background: var(--deep-gray);
      border-radius: var(--radius-card);
      margin-bottom: 1rem;
      cursor: pointer;
    }
    .faq-question {
      padding: 1.5rem;
      display: flex;
      justify-content: space-between;
      font-weight: 600;
    }
    .faq-answer {
      padding: 0 1.5rem 1.5rem;
      display: none;
      border-left: 3px solid var(--electric-violet);
      margin-left: 1rem;
    }
    .faq-item.active .faq-answer {
      display: block;
    }

    /* CTA */
    #cta {
      background: radial-gradient(circle at center, rgba(123,47,255,0.2), transparent);
      text-align: center;
    }

    /* 页脚 */
    .footer-grid {
      display: flex;
      justify-content: space-between;
      align-items: center;
      padding: 2rem 0;
      border-top: 1px solid rgba(255,255,255,0.05);
    }
    @media (max-width: 768px) {
      .footer-grid { flex-direction: column; gap: 1rem; }
    }