/* roulang page: index */
:root {
      --primary-dark: #0A0E27;
      --deep-bg: #060B1A;
      --accent-cyan: #00F0FF;
      --accent-red: #FF4655;
      --bg-light: #F5F6FA;
      --card-bg: #FFFFFF;
      --text-main: #1A1A2E;
      --text-secondary: #5A5A72;
      --text-on-dark: #FFFFFF;
      --success: #00E676;
      --warning: #FFB800;
      --border-light: rgba(0,0,0,0.04);
      --border-input: #DDE1E8;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.06);
      --shadow-glow: 0 8px 30px rgba(0,240,255,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-tag: 6px;
      --font-sans: 'Noto Sans SC', sans-serif;
      --font-mono: 'Roboto Mono', monospace;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--bg-light);
      color: var(--text-main);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    h1, h2, h3, h4 {
      font-weight: 700;
      line-height: 1.3;
    }
    h1 {
      font-size: clamp(2.5rem, 6vw, 3.5rem);
      line-height: 1.2;
    }
    h2 {
      font-size: clamp(2rem, 4vw, 2.5rem);
      margin-bottom: 16px;
    }
    h3 {
      font-size: 1.4rem;
      margin-bottom: 12px;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s, background 0.2s;
    }
    img {
      max-width: 100%;
      display: block;
    }
    button, input, textarea {
      font-family: inherit;
    }
    /* 导航 */
    #header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: transparent;
      transition: background 0.3s, backdrop-filter 0.3s, box-shadow 0.3s;
      height: 72px;
      display: flex;
      align-items: center;
    }
    #header.scrolled {
      background: rgba(6,11,26,0.85);
      backdrop-filter: blur(12px);
      box-shadow: 0 4px 20px rgba(0,0,0,0.2);
    }
    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    .logo {
      font-size: 1.8rem;
      font-weight: 700;
      color: #fff;
      letter-spacing: 2px;
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .logo i {
      color: var(--accent-cyan);
      font-size: 2rem;
      text-shadow: 0 0 12px rgba(0,240,255,0.5);
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .nav-links a {
      color: rgba(255,255,255,0.8);
      font-weight: 500;
      font-size: 0.95rem;
      position: relative;
      padding: 8px 0;
    }
    .nav-links a:hover, .nav-links a.active {
      color: #fff;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent-cyan);
      transition: width 0.25s;
    }
    .nav-links a:hover::after, .nav-links a.active::after {
      width: 100%;
    }
    .nav-cta {
      background: var(--accent-cyan);
      color: var(--primary-dark);
      padding: 10px 22px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      font-size: 0.9rem;
      transition: all 0.25s;
      box-shadow: 0 0 12px rgba(0,240,255,0.4);
    }
    .nav-cta:hover {
      box-shadow: 0 0 22px rgba(0,240,255,0.7);
      transform: scale(1.02);
    }
    .hamburger {
      display: none;
      font-size: 1.8rem;
      color: #fff;
      background: none;
      border: none;
      cursor: pointer;
    }
    /* 移动菜单 */
    .mobile-menu {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100vh;
      background: var(--deep-bg);
      flex-direction: column;
      justify-content: center;
      align-items: center;
      gap: 32px;
      z-index: 999;
      opacity: 0;
      transform: translateY(-10px);
      transition: 0.3s;
    }
    .mobile-menu.active {
      display: flex;
      opacity: 1;
      transform: translateY(0);
    }
    .mobile-menu a {
      color: #fff;
      font-size: 1.6rem;
      font-weight: 600;
    }
    /* 区块 */
    section {
      padding: 120px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 80px 0;
      }
      #header {
        height: 60px;
      }
    }
    /* Hero */
    #hero {
      height: 100vh;
      min-height: 650px;
      background: radial-gradient(circle at 30% 40%, #0A0E27, #060B1A);
      display: flex;
      align-items: center;
      position: relative;
      overflow: hidden;
    }
    .hero-bg {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      opacity: 0.35;
    }
    .hero-content {
      position: relative;
      z-index: 2;
      max-width: 800px;
      color: #fff;
    }
    .hero-content h1 {
      text-shadow: 0 0 35px rgba(0,240,255,0.7);
      margin-bottom: 24px;
    }
    .hero-content .subtitle {
      font-size: 1.2rem;
      color: rgba(255,255,255,0.7);
      margin-bottom: 36px;
      max-width: 600px;
    }
    .btn-group {
      display: flex;
      gap: 20px;
      flex-wrap: wrap;
    }
    .btn {
      display: inline-block;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 1rem;
      transition: all 0.25s;
      text-align: center;
    }
    .btn-primary {
      background: var(--accent-cyan);
      color: var(--primary-dark);
      box-shadow: 0 0 18px rgba(0,240,255,0.5);
    }
    .btn-primary:hover {
      box-shadow: 0 0 28px rgba(0,240,255,0.8);
      transform: scale(1.03);
    }
    .btn-outline {
      border: 2px solid var(--accent-cyan);
      color: var(--accent-cyan);
      background: transparent;
    }
    .btn-outline:hover {
      background: rgba(0,240,255,0.1);
    }
    .btn-danger {
      background: var(--accent-red);
      color: #fff;
      box-shadow: 0 0 15px rgba(255,70,85,0.4);
    }
    .btn-danger:hover {
      background: #E83645;
      transform: scale(1.05);
    }
    .scroll-indicator {
      position: absolute;
      bottom: 30px;
      left: 50%;
      transform: translateX(-50%);
      color: var(--accent-cyan);
      font-size: 2rem;
      animation: pulse 2s infinite;
    }
    @keyframes pulse {
      0% { opacity: 0.6; transform: translateX(-50%) translateY(0); }
      50% { opacity: 1; transform: translateX(-50%) translateY(8px); }
      100% { opacity: 0.6; transform: translateX(-50%) translateY(0); }
    }
    /* 通用卡片网格 */
    .grid-3, .grid-4 {
      display: grid;
      gap: 32px;
    }
    .grid-3 { grid-template-columns: repeat(3, 1fr); }
    .grid-4 { grid-template-columns: repeat(4, 1fr); }
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-card);
      border: 1px solid var(--border-light);
      transition: all 0.3s;
    }
    .card:hover {
      transform: translateY(-6px);
      box-shadow: var(--shadow-glow);
    }
    .icon-lg {
      font-size: 3rem;
      color: var(--accent-cyan);
      margin-bottom: 20px;
    }
    /* 数据条 */
    #stats {
      background: var(--deep-bg);
      color: #fff;
    }
    .stats-grid {
      display: flex;
      justify-content: space-around;
      text-align: center;
    }
    .stat-number {
      font-family: var(--font-mono);
      font-size: 3.2rem;
      color: var(--accent-cyan);
      font-weight: 600;
    }
    /* 案例卡片 */
    .case-card {
      position: relative;
      border-radius: var(--radius-card);
      overflow: hidden;
    }
    .case-card img {
      aspect-ratio: 4/3;
      object-fit: cover;
    }
    .case-overlay {
      position: absolute;
      bottom: 0;
      background: rgba(10,14,39,0.8);
      width: 100%;
      padding: 20px;
      color: #fff;
    }
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid #e0e0e0;
      padding: 18px 0;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      font-weight: 700;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease;
      color: var(--text-secondary);
    }
    /* 联系 */
    .contact-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 48px;
    }
    input, textarea {
      width: 100%;
      padding: 14px;
      border: 1px solid var(--border-input);
      border-radius: var(--radius-btn);
      margin-bottom: 16px;
      transition: 0.2s;
    }
    input:focus, textarea:focus {
      border-color: var(--accent-cyan);
      box-shadow: 0 0 8px rgba(0,240,255,0.2);
      outline: none;
    }
    footer {
      background: var(--deep-bg);
      color: #ccc;
      padding: 60px 0 30px;
    }
    @media (max-width: 1024px) {
      .grid-3 { grid-template-columns: repeat(2,1fr); }
      .grid-4 { grid-template-columns: repeat(2,1fr); }
      .contact-grid { grid-template-columns: 1fr; }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: block; }
      .grid-3, .grid-4 { grid-template-columns: 1fr; }
      .stats-grid { flex-direction: column; gap: 32px; }
      .btn-group { flex-direction: column; align-items: flex-start; }
    }