/* roulang page: index */
/* :root 设计系统变量 */
    :root {
      --primary-dark: #1A0A2E;
      --accent-cyan: #00E5FF;
      --cta-orange: #FF6D00;
      --bg-dark: #0D0D0D;
      --text-white: #F0F0F0;
      --text-gray: #9E9E9E;
      --text-light: #BDBDBD;
      --border-subtle: rgba(0, 229, 255, 0.15);
      
      --glass-bg: rgba(26, 10, 46, 0.7);
      --glass-blur: blur(12px);
      
      --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.4);
      --shadow-glow: 0 12px 40px rgba(0, 229, 255, 0.15);
      --shadow-orange: 0 0 20px rgba(255, 109, 0, 0.5);
      
      --font-stack: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      
      --radius-lg: 16px;
      --radius-md: 10px;
      --radius-sm: 8px;
      
      --spacing-section: 100px;
      --container-max: 1280px;
      
      transition: background-color 0.25s ease, color 0.25s ease;
    }
    
    /* 基础重置与全局样式 */
    *, *::before, *::after {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    
    html {
      scroll-behavior: smooth;
      font-size: 16px;
    }
    
    body {
      font-family: var(--font-stack);
      background-color: var(--bg-dark);
      color: var(--text-white);
      line-height: 1.7;
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.25s, border-bottom 0.2s;
    }
    
    button, input, textarea {
      font-family: inherit;
      outline: none;
      border: none;
    }
    
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    
    /* 排版工具类 */
    h1, h2, h3, .h1, .h2, .h3 {
      font-weight: 700;
      letter-spacing: -0.02em;
    }
    
    h2 {
      font-size: 2.8rem;
      text-align: center;
      margin-bottom: 20px;
      color: var(--text-white);
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 12px;
    }
    
    h2::after {
      content: '';
      width: 60px;
      height: 3px;
      background: var(--accent-cyan);
      display: block;
      margin-top: 4px;
    }
    
    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 14px 32px;
      border-radius: var(--radius-md);
      font-weight: 600;
      font-size: 1rem;
      transition: all 0.25s ease;
      cursor: pointer;
      text-align: center;
      white-space: nowrap;
    }
    
    .btn-primary {
      background: var(--cta-orange);
      color: #fff;
      border: none;
      box-shadow: 0 4px 12px rgba(255, 109, 0, 0.3);
    }
    
    .btn-primary:hover {
      background: #FF8F33;
      box-shadow: var(--shadow-orange);
      transform: translateY(-1px);
    }
    
    .btn-secondary {
      background: transparent;
      border: 1.5px solid var(--accent-cyan);
      color: var(--accent-cyan);
    }
    
    .btn-secondary:hover {
      background: rgba(0, 229, 255, 0.15);
      box-shadow: 0 0 16px rgba(0, 229, 255, 0.3);
    }
    
    .btn-ghost {
      background: transparent;
      color: var(--text-white);
      padding: 8px 0;
      border-bottom: 1px solid transparent;
    }
    
    .btn-ghost:hover {
      color: var(--accent-cyan);
      border-bottom-color: var(--accent-cyan);
    }
    
    /* 导航系统 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: rgba(13, 13, 13, 0.85);
      backdrop-filter: blur(16px);
      -webkit-backdrop-filter: blur(16px);
      border-bottom: 1px solid var(--border-subtle);
      transition: background 0.3s, box-shadow 0.3s;
    }
    
    .site-header.scrolled {
      background: rgba(13, 13, 13, 0.95);
      box-shadow: 0 4px 20px rgba(0,0,0,0.5);
    }
    
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 68px;
    }
    
    .logo-area {
      display: flex;
      align-items: baseline;
      gap: 8px;
    }
    
    .logo-text {
      font-size: 1.8rem;
      font-weight: 800;
      color: var(--text-white);
      letter-spacing: 0.5px;
    }
    
    .logo-domain {
      font-size: 0.75rem;
      color: var(--text-gray);
      font-weight: 400;
    }
    
    .nav-links {
      display: flex;
      gap: 28px;
      align-items: center;
    }
    
    .nav-links a {
      color: var(--text-white);
      font-weight: 500;
      padding: 8px 0;
      position: relative;
    }
    
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--accent-cyan);
    }
    
    .hamburger {
      display: none;
      color: var(--text-white);
      font-size: 1.6rem;
      background: none;
      border: none;
      cursor: pointer;
    }
    
    /* 移动端菜单 */
    .mobile-menu {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: rgba(13, 13, 13, 0.98);
      backdrop-filter: blur(20px);
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 36px;
      font-size: 1.8rem;
      transform: translateY(-100%);
      transition: transform 0.35s ease;
      z-index: 999;
    }
    
    .mobile-menu.is-open {
      transform: translateY(0);
    }
    
    .mobile-menu a {
      color: var(--text-white);
      font-weight: 600;
    }
    
    .mobile-menu a:hover {
      color: var(--accent-cyan);
    }
    
    /* 各区块通用间距 */
    section {
      padding: var(--spacing-section) 0;
    }
    
    /* Hero 首屏 */
    .hero {
      height: 100vh;
      min-height: 700px;
      display: flex;
      align-items: center;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      position: relative;
      color: white;
    }
    
    .hero-overlay {
      position: absolute;
      inset: 0;
      background: linear-gradient(180deg, rgba(26,10,46,0.8) 10%, rgba(13,13,13,0.7) 70%);
      z-index: 1;
    }
    
    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 800px;
      text-align: center;
      animation: fadeInUp 0.8s ease-out;
    }
    
    .hero h1 {
      font-size: clamp(2.5rem, 5vw, 4.5rem);
      font-weight: 800;
      line-height: 1.1;
      margin-bottom: 20px;
      text-shadow: 0 4px 20px rgba(0,0,0,0.5);
    }
    
    .hero .subtitle {
      font-size: 1.25rem;
      color: var(--text-light);
      margin-bottom: 40px;
    }
    
    .hero-buttons {
      display: flex;
      gap: 20px;
      justify-content: center;
      flex-wrap: wrap;
    }
    
    @keyframes fadeInUp {
      from { opacity: 0; transform: translateY(25px); }
      to { opacity: 1; transform: translateY(0); }
    }
    
    /* 优势卡片区 */
    .advantages-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      margin-top: 40px;
    }
    
    .adv-item {
      background: var(--glass-bg);
      backdrop-filter: var(--glass-blur);
      border: 1px solid var(--border-subtle);
      border-radius: var(--radius-lg);
      padding: 32px 20px;
      text-align: center;
      transition: transform 0.2s, box-shadow 0.3s;
    }
    
    .adv-item:hover {
      transform: translateY(-5px);
      box-shadow: var(--shadow-glow);
    }
    
    .adv-icon {
      font-size: 2.4rem;
      color: var(--accent-cyan);
      margin-bottom: 18px;
    }
    
    .adv-title {
      font-size: 1.3rem;
      font-weight: 600;
      margin-bottom: 10px;
    }
    
    /* 服务矩阵交错卡片 */
    .service-row {
      display: flex;
      align-items: center;
      gap: 40px;
      margin-bottom: 60px;
    }
    
    .service-row.reverse {
      flex-direction: row-reverse;
    }
    
    .service-img {
      flex: 1 1 45%;
      border-radius: var(--radius-lg);
      overflow: hidden;
      box-shadow: var(--shadow-card);
    }
    
    .service-img img {
      width: 100%;
      object-fit: cover;
      transition: transform 0.3s;
    }
    
    .service-row:hover .service-img img {
      transform: scale(1.03);
    }
    
    .service-text {
      flex: 1 1 50%;
    }
    
    .service-text h3 {
      color: var(--accent-cyan);
      font-size: 1.8rem;
    }
    
    .tags {
      display: flex;
      flex-wrap: wrap;
      gap: 10px;
      margin-top: 18px;
    }
    
    .tag {
      background: rgba(0,229,255,0.1);
      border: 1px solid var(--accent-cyan);
      color: var(--accent-cyan);
      padding: 4px 14px;
      border-radius: 20px;
      font-size: 0.85rem;
    }
    
    /* 数据滚动区 */
    .data-strip {
      display: flex;
      justify-content: space-around;
      text-align: center;
      flex-wrap: wrap;
    }
    
    .data-item .number {
      font-size: 3rem;
      font-weight: 800;
      color: var(--cta-orange);
    }
    
    /* 流程步骤 */
    .process-steps {
      display: flex;
      justify-content: space-between;
      position: relative;
    }
    
    .step {
      text-align: center;
      flex:1;
    }
    
    /* FAQ */
    .faq-item {
      background: #151515;
      border-left: 3px solid var(--accent-cyan);
      margin-bottom: 12px;
      border-radius: 6px;
      
    }
    
    .faq-question {
      padding: 16px 24px;
      font-weight: 600;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
    }
    
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      padding: 0 24px;
      color: var(--text-light);
      transition: max-height 0.3s ease, padding 0.3s;
    }
    
    .faq-item.active .faq-answer {
      max-height: 150px;
      padding: 16px 24px;
    }
    
    /* 表单 */
    .contact-form input, .contact-form textarea {
      background: #1E1E1E;
      border: 1px solid #333;
      border-radius: var(--radius-sm);
      padding: 14px;
      width: 100%;
      color: white;
      margin-bottom: 18px;
      transition: 0.2s;
    }
    
    .contact-form input:focus, .contact-form textarea:focus {
      border-color: var(--accent-cyan);
      box-shadow: 0 0 0 3px rgba(0, 229, 255, 0.2);
    }
    
    footer {
      background: #0A0A0A;
      color: #757575;
    }
    
    @media (max-width: 1024px) {
      .advantages-grid { grid-template-columns: repeat(2,1fr); }
      .service-row, .service-row.reverse { flex-direction: column; }
    }
    
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: block; }
      .advantages-grid { grid-template-columns: 1fr; }
      .data-strip { gap: 30px; }
    }