/* roulang page: index */
:root {
      --bg-deep: #0A0E27;
      --bg-darker: #060B1A;
      --cyan: #00F0FF;
      --red: #FF4655;
      --gold: #FFD700;
      --text-primary: #FFFFFF;
      --text-body: #B0C4DE;
      --text-muted: #6B7B8D;
      --surface-alpha: rgba(255, 255, 255, 0.04);
      --glass-border: rgba(255, 255, 255, 0.08);
      --glass-hover-border: rgba(0, 240, 255, 0.3);
      --card-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
      --section-padding: 5rem 1.5rem;
      --border-radius-card: 16px;
      --border-radius-btn: 8px;
      --border-radius-image: 12px;
      --transition-smooth: all 0.3s cubic-bezier(0.25, 0.8, 0.25, 1.2);
      --font-heading: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --font-body: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --font-mono: 'SF Mono', 'Menlo', monospace;
    }

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

    body {
      background-color: var(--bg-deep);
      font-family: var(--font-body);
      line-height: 1.7;
      color: var(--text-body);
      font-weight: 400;
      -webkit-font-smoothing: antialiased;
    }

    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 1.5rem;
    }

    h1, h2, h3 {
      font-family: var(--font-heading);
      font-weight: 700;
      letter-spacing: -0.02em;
      color: var(--text-primary);
    }

    h1 {
      font-size: clamp(2.5rem, 8vw, 3.5rem);
      line-height: 1.2;
    }
    h2 {
      font-size: clamp(1.8rem, 5vw, 2.4rem);
      margin-bottom: 1.5rem;
    }
    h3 {
      font-size: clamp(1.3rem, 3vw, 1.7rem);
    }
    p {
      color: var(--text-body);
      font-size: 1rem;
    }
    a {
      color: var(--cyan);
      text-decoration: none;
      transition: var(--transition-smooth);
    }
    a:hover {
      color: #fff;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }

    /* 按钮系统 */
    .btn-primary {
      background: var(--cyan);
      color: var(--bg-deep);
      font-weight: 700;
      border: none;
      padding: 14px 34px;
      border-radius: var(--border-radius-btn);
      letter-spacing: 0.05em;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 0.5rem;
      box-shadow: 0 0 15px rgba(0,240,255,0.4);
      cursor: pointer;
      transition: var(--transition-smooth);
      font-family: var(--font-heading);
    }
    .btn-primary:hover {
      background: #33f5ff;
      box-shadow: 0 0 28px rgba(0,240,255,0.7);
      transform: scale(1.03);
      color: var(--bg-deep);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--cyan);
      color: var(--cyan);
      padding: 12px 30px;
      border-radius: var(--border-radius-btn);
      font-weight: 600;
      cursor: pointer;
      transition: var(--transition-smooth);
      display: inline-flex;
      align-items: center;
      gap: 0.5rem;
    }
    .btn-outline:hover {
      background: rgba(0,240,255,0.08);
      border-color: #33f5fc;
      color: #fff;
    }
    .btn-red {
      background: var(--red);
      color: #fff;
      border: none;
      box-shadow: 0 0 18px rgba(255,70,85,0.5);
    }
    .btn-red:hover {
      background: #ff5e6b;
      box-shadow: 0 0 30px rgba(255,70,85,0.8);
    }
    .card, .glass-card {
      background: rgba(255,255,255,0.03);
      backdrop-filter: blur(12px);
      border: 1px solid var(--glass-border);
      border-radius: var(--border-radius-card);
      box-shadow: var(--card-shadow);
      transition: var(--transition-smooth);
    }
    .glass-card:hover {
      border-color: var(--glass-hover-border);
      box-shadow: 0 16px 48px rgba(0,0,0,0.6), 0 0 25px rgba(0,240,255,0.2);
      transform: translateY(-6px);
    }

        /* 导航 */
    .navbar {
      position: fixed;
      top: 0;
      width: 100%;
      z-index: 100;
      background: rgba(10,14,39,0.8);
      backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(0,240,255,0.15);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .logo {
      font-family: var(--font-heading);
      font-weight: 900;
      font-size: 1.9rem;
      color: var(--cyan);
      letter-spacing: 0.02em;
      display: flex;
      align-items: center;
      gap: 0.25rem;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 2.2rem;
      list-style: none;
    }
    .nav-links a {
      color: var(--text-body);
      font-weight: 600;
      font-size: 1rem;
    }
    .nav-links a:hover {
      color: var(--cyan);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      justify-content: space-around;
      width: 28px;
      height: 24px;
      background: transparent;
      border: none;
      cursor: pointer;
      z-index: 120;
    }
    .hamburger span {
      width: 100%;
      height: 2px;
      background: var(--cyan);
      transition: 0.3s;
    }
    .mobile-menu {
      display: none;
      position: fixed;
      inset: 0;
      background: rgba(10,14,39,0.98);
      backdrop-filter: blur(18px);
      justify-content: center;
      align-items: center;
      text-align: center;
      z-index: 110;
      flex-direction: column;
      gap: 2.2rem;
    }
    .mobile-menu a {
      font-size: 1.5rem;
      color: #fff;
    }
    
    /* hero */
    .hero {
      min-height: 100vh;
      display: flex;
      align-items: center;
      background: radial-gradient(circle at 30% 50%, rgba(0,240,255,0.05) 0%, transparent 60%);
      padding-top: 80px;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1.1fr 0.9fr;
      gap: 3rem;
      align-items: center;
    }
    .sub-title {
      font-size: 1.2rem;
      margin: 1.8rem 0 2.5rem;
      max-width: 550px;
    }
    .stat-panel {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 1.5rem;
      position: relative;
    }
    .stat-card {
      background: rgba(255,255,255,0.03);
      backdrop-filter: blur(10px);
      border: 1px solid rgba(255,255,255,0.1);
      border-radius: 20px;
      padding: 1.6rem;
      text-align: center;
    }
    .stat-num {
      font-family: var(--font-mono);
      font-size: 2.2rem;
      font-weight: bold;
      color: var(--gold);
    }
    
        .bg-picture-cover {
      border-radius: 24px;
      overflow: hidden;
      box-shadow: 0 20px 40px rgba(0,0,0,0.6);
      background: rgba(0,240,255,0.03);
    }

    @media (max-width: 860px) {
      .hero-grid {
        grid-template-columns: 1fr;
        text-align: center;
      }
      .sub-title {
        margin-inline: auto;
      }
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .contact-btn-nav { display: none; }
    }
    @media (max-width: 640px){
      .container { padding: 0 1rem; }
    }
        /* cards */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
      gap: 2rem;
    }
    img.cover{
      width: 100%;
      height: 190px;
      object-fit: cover;
      border-radius: 14px 14px 0 0;
    }
  footer {
    background: var(--bg-darker);
    border-top: 1px solid rgba(0,240,255,0.18);
    padding: 3.5rem 0 1.8rem;
    color: var(--text-muted);
  }