/* roulang page: index */
/* 全局设计变量与重置 */
    :root {
      --primary: #7B2FF7;
      --secondary: #00F0FF;
      --dark-bg: #12121A;
      --card-bg: rgba(30, 28, 48, 0.9);
      --card-solid: #1E1C30;
      --accent: #FF6B35;
      --text-primary: #F0F0F5;
      --text-secondary: #A0A0B0;
      --border-light: rgba(0, 240, 255, 0.25);
      --gradient-main: 135deg, #7B2FF7 0%, #00F0FF 100%;
      --radius-card: 16px;
      --radius-btn: 10px;
      --radius-circle: 24px;
      --shadow-card: 0 4px 24px rgba(123, 47, 247, 0.15);
      --shadow-hover: 0 8px 40px rgba(0, 240, 255, 0.25);
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Noto Sans SC", "Inter", system-ui, sans-serif;
      --transition: 0.25s ease;
      --container-max: 1280px;
      --nav-height: 68px;
    }

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

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

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

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      transition: all var(--transition);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      font-weight: 600;
      border-radius: var(--radius-btn);
    }

    h1, h2, h3 {
      font-weight: 700;
      line-height: 1.3;
    }

    h1 {
      font-size: clamp(2.2rem, 6vw, 3.8rem);
      margin-bottom: 1.2rem;
      letter-spacing: -0.5px;
    }

    h2 {
      font-size: clamp(1.8rem, 4vw, 2.6rem);
      margin-bottom: 1.5rem;
      text-align: center;
      position: relative;
      display: inline-block;
      width: 100%;
    }

    h3 {
      font-size: 1.3rem;
      font-weight: 600;
      color: var(--primary);
      margin-bottom: 0.5rem;
    }

    .section {
      padding: 90px 0;
    }

    @media (max-width: 768px) {
      .section {
        padding: 60px 0;
      }
      .container {
        padding: 0 20px;
      }
    }

    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--nav-height);
      background: rgba(255, 255, 255, 0.08);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      z-index: 1000;
      border-bottom: 1px solid rgba(0, 240, 255, 0.1);
      transition: box-shadow 0.3s;
    }

    .header.scrolled {
      box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
    }

    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
    }

    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-size: 1.6rem;
      font-weight: 700;
      color: white;
      letter-spacing: 1px;
    }
    .logo i {
      color: var(--secondary);
      font-size: 1.8rem;
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 2rem;
      list-style: none;
    }

    .nav-menu a {
      color: var(--text-primary);
      font-weight: 500;
      font-size: 0.95rem;
      padding: 5px 0;
      border-bottom: 2px solid transparent;
      transition: 0.2s;
    }

    .nav-menu a:hover,
    .nav-menu a.active {
      color: var(--secondary);
      border-bottom-color: var(--secondary);
    }

    .btn-primary {
      background: var(--accent);
      color: white;
      padding: 12px 28px;
      box-shadow: 0 4px 12px rgba(255, 107, 53, 0.4);
    }
    .btn-primary:hover {
      background: #FF8255;
      box-shadow: 0 0 20px rgba(0, 240, 255, 0.5);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
    }
    .hamburger span {
      width: 26px;
      height: 2.5px;
      background: white;
      border-radius: 2px;
      transition: 0.3s;
    }

    @media (max-width: 768px) {
      .nav-menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 75%;
        max-width: 320px;
        height: 100vh;
        background: var(--dark-bg);
        flex-direction: column;
        justify-content: center;
        gap: 2.2rem;
        transition: 0.4s ease;
        backdrop-filter: blur(20px);
        background: rgba(18, 18, 26, 0.95);
      }
      .nav-menu.active {
        right: 0;
      }
      .hamburger {
        display: flex;
        z-index: 1001;
      }
    }

    /* Hero */
    .hero {
      min-height: 90vh;
      display: flex;
      align-items: center;
      background: linear-gradient(135deg, #7B2FF7 0%, #00F0FF 100%);
      position: relative;
      overflow: hidden;
      margin-top: var(--nav-height);
    }
    .hero::before {
      content: "";
      position: absolute;
      inset: 0;
      background-image: linear-gradient(rgba(0,240,255,0.08) 1px, transparent 1px), linear-gradient(90deg, rgba(0,240,255,0.08) 1px, transparent 1px);
      background-size: 40px 40px;
      pointer-events: none;
    }
    .hero-content {
      display: flex;
      align-items: center;
      justify-content: space-between;
      flex-wrap: wrap;
      position: relative;
      z-index: 2;
    }
    .hero-text {
      flex: 1 1 500px;
      color: white;
    }
    .hero-text h1 {
      color: white;
      text-shadow: 0 4px 20px rgba(0,0,0,0.3);
    }
    .hero-text p {
      font-size: 1.2rem;
      color: rgba(255,255,255,0.9);
      margin-bottom: 2rem;
    }
    .hero-image {
      flex: 1 1 400px;
      display: flex;
      justify-content: center;
    }
    .hero-image img {
      border-radius: 20px;
      box-shadow: 0 0 30px rgba(0,240,255,0.6);
      max-width: 100%;
      height: auto;
    }
    @media (max-width: 768px) {
      .hero-content {
        flex-direction: column;
        text-align: center;
        gap: 2rem;
      }
      .hero-text, .hero-image {
        flex: unset;
        width: 100%;
      }
    }

    /* 卡片网格 */
    .grid-3, .grid-4, .grid-2 {
      display: grid;
      gap: 28px;
      margin-top: 2.5rem;
    }
    .grid-3 { grid-template-columns: repeat(3, 1fr); }
    .grid-4 { grid-template-columns: repeat(4, 1fr); }
    .grid-2 { grid-template-columns: repeat(2, 1fr); }

    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 28px;
      box-shadow: var(--shadow-card);
      transition: all 0.3s ease;
      border: 1px solid transparent;
    }
    .card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-hover);
      border-color: var(--secondary);
    }
    .service-icon {
      width: 64px;
      height: 64px;
      border-radius: 20px;
      background: linear-gradient(135deg, #00F0FF33, #7B2FF733);
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 1.2rem;
      overflow: hidden;
    }
    .service-icon img {
      width: 100%;
      height: 100%;
      object-fit: cover;
    }

    .data-wall {
      background: var(--card-solid);
      border-radius: 24px;
      padding: 40px 20px;
      backdrop-filter: blur(8px);
    }
    .stat-item {
      text-align: center;
    }
    .stat-number {
      font-size: 3rem;
      font-weight: 800;
      background: linear-gradient(135deg, #7B2FF7, #00F0FF);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
      line-height: 1.2;
    }

    .case-img {
      aspect-ratio: 16/9;
      background: #2a2a3a;
      border-radius: 12px;
      overflow: hidden;
      margin-bottom: 1rem;
    }
    .case-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      transition: transform 0.3s;
    }
    .card:hover .case-img img {
      transform: scale(1.03);
    }

    .steps {
      display: flex;
      justify-content: space-between;
      align-items: center;
      flex-wrap: wrap;
      gap: 1rem;
    }
    .step {
      flex: 1;
      text-align: center;
    }
    .step-num {
      font-size: 4rem;
      font-weight: 800;
      background: linear-gradient(135deg, #7B2FF7, #00F0FF);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      opacity: 0.7;
    }

    .faq-item {
      border-bottom: 1px solid rgba(0,240,255,0.2);
      padding: 16px 0;
      cursor: pointer;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-secondary);
      margin-top: 0;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      margin-top: 12px;
    }

    .cta-banner {
      background: linear-gradient(135deg, #7B2FF7, #00F0FF);
      border-radius: 24px;
      padding: 70px 30px;
      text-align: center;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 2rem;
    }
    @media (max-width: 768px) {
      .grid-3, .grid-2 { grid-template-columns: 1fr; }
      .grid-4 { grid-template-columns: repeat(2, 1fr); }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .steps { flex-direction: column; }
    }
    @media (max-width: 480px) {
      .footer-grid { grid-template-columns: 1fr; }
    }