/* Global Styles */
    body {
      font-family: 'Poppins', sans-serif;
      background: linear-gradient(135deg, #f7f7f7, #eaeaea);
      color: #333;
      padding-top: 70px;
    }
    /* Navbar */
    .navbar {
      background: rgba(0, 0, 0, 0.85);
      box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    }
    .navbar-brand {
      font-weight: 700;
      font-size: 1.5rem;
    }
    .navbar-nav .nav-link {
      font-weight: 500;
      transition: color 0.3s, transform 0.3s;
      margin-right: 10px;
    }
    .navbar-nav .nav-link:hover {
      color: #f0ad4e;
      transform: scale(1.05);
    }
    /* Hero Section */
    .hero {
      background: url('imagenes/libro-llaves.webp') no-repeat center center;
      background-size: cover;
      position: relative;
      height: 500px;
      margin-bottom: 30px;
      border-bottom: 5px solid #f0ad4e;
    }
    .hero::after {
      content: "";
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: rgba(0, 0, 0, 0.5);
    }
    .hero h1 {
      position: relative;
      z-index: 1;
      color: #fff;
      text-align: center;
      padding-top: 100px;
      font-size: 2.8rem;
      text-shadow: 2px 2px 6px rgba(0,0,0,0.7);
      font-weight: 700;
    }
    /* Filter Card */
    .filter-card {
      border-radius: 15px;
      box-shadow: 0 8px 16px rgba(0,0,0,0.15);
      background: #fff;
      padding: 25px;
      margin-bottom: 30px;
    }
    .filter-card p {
      font-style: italic;
      color: #555;
    }
    /* Key Cards */
    .key-card {
      transition: transform 0.3s, box-shadow 0.3s;
      border: none;
      border-radius: 15px;
      overflow: hidden;
      background: #fff;
    }
    .key-card:hover {
      transform: translateY(-10px);
      box-shadow: 0 12px 25px rgba(0,0,0,0.25);
    }
    .key-card img {
      border-top-left-radius: 15px;
      border-top-right-radius: 15px;
      height: 200px;
      object-fit: contain;
    }
    .card-body {
      padding: 1rem;
    }
    .card-title {
      font-weight: 600;
    }
    .card-text {
      font-size: 0.95rem;
    }
    /* Modal Custom */
    .modal-content {
      border-radius: 15px;
    }
    /* Sidebar */
    .sidebar {
      margin-bottom: 30px;
    }
    .sidebar h4 {
      margin-bottom: 20px;
      font-weight: 600;
      color: #f0ad4e;
      border-bottom: 2px solid #f0ad4e;
      padding-bottom: 5px;
    }
    .sidebar .card {
      margin-bottom: 15px;
      transition: transform 0.3s;
    }
    .sidebar .card:hover {
      transform: translateX(5px);
    }
    .sidebar .card a {
      color: #333;
      text-decoration: none;
    }
    .sidebar .card a:hover {
      color: #f0ad4e;
    }
    /* Content Wrapper */
    .content-wrapper {
      padding-top: 30px;
      padding-bottom: 30px;
    }
    /* Footer */
    footer {
      background: #222;
      color: #ddd;
      padding: 30px 0;
    }
    footer h5 {
      font-weight: 600;
      color: #f0ad4e;
    }
    footer p, footer a {
      font-size: 0.95rem;
    }
    footer a {
      color: #ddd;
      text-decoration: none;
    }
    footer a:hover {
      color: #f0ad4e;
    }
    .btn-social {
      border-radius: 50%;
      width: 40px;
      height: 40px;
      padding: 0;
      line-height: 38px;
    }


    .cluster-section {
      background-size: cover;
      background-position: center;
      border-radius: 10px;
      box-shadow: 0 4px 6px rgba(0,0,0,0.1);
      transition: transform 0.3s ease, box-shadow 0.3s ease;
      position: relative;
      overflow: hidden;
      min-height: 200px;
      text-decoration: none;
      color: inherit;
    }
    .cluster-section:hover {
      transform: translateY(-5px);
      box-shadow: 0 8px 12px rgba(0,0,0,0.2);
    }
    .cluster-overlay {
      background: rgba(0, 0, 0, .8);
      height: 100%;
      position: absolute;
      top: 0;
      left: 0;
      right: 0;
      bottom: 0;
      display: flex;
      flex-direction: column;
      justify-content: center;
      align-items: center;
      color: #fff;
      padding: 1rem;
      text-align: center;
    }
    .cluster-overlay h3 {
      margin-bottom: 0.5rem;
    }