    /* Classic Theme Custom Variables - Minimalist Design */
    :root {
        --classic-primary: #2e2e2e; /* Gris Carbón - Changed for better button visibility */
        --classic-secondary: #444444; /* Gris Medianoche - Changed for better contrast */
        --classic-accent: #dadada; /* Gris Ceniza Claro */
        --classic-light: #f5f5f5; /* Gris Niebla */
        --classic-dark: #2e2e2e; /* Gris Carbón */
        --classic-success: #444444; /* Gris Medianoche */
        --classic-warning: #1a1a1a; /* Negro Suave */
        --classic-danger: #2e2e2e;
        --classic-info: #444444;
        --classic-text: #2e2e2e; /* Texto principal */
        --classic-text-secondary: #444444; /* Texto secundario */
    }

    .bd-placeholder-img {
        font-size: 1.125rem;
        text-anchor: middle;
        -webkit-user-select: none;
        -moz-user-select: none;
        user-select: none;
    }

    @media (min-width: 768px) {
        .bd-placeholder-img-lg {
            font-size: 3.5rem;
        }
    }

    /* Classic Theme Styles */
    body {
        background: #ffffff;
        font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    }

    /* Custom Navbar Styling */
    .navbar-classic {
        background: #ffffff !important; /* Keep navbar white */
        box-shadow: 0 2px 4px rgba(15, 108, 191, 0.1);
    }

    .navbar-classic .navbar-brand,
    .navbar-classic .nav-link {
        color: var(--classic-dark) !important;
        font-weight: 500;
        transition: all 0.2s ease;
    }

    .navbar-classic .nav-link:hover {
        color: var(--classic-light) !important;
        background-color: rgba(255, 255, 255, 0.1);
        border-radius: 4px;
        transform: translateY(-1px);
    }

    .navbar-classic .navbar-toggler {
        border-color: rgba(46, 46, 46, 0.3);
    }

    .navbar-classic .navbar-toggler-icon {
        background-image: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3e%3cpath stroke='rgba%280, 0, 0, 1%29' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2' d='m4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e");
    }

    /* Custom Button Styles */
    .btn-classic-primary {
        background-color: var(--classic-primary);
        border-color: var(--classic-primary);
        color: white;
        border-radius: 4px;
        padding: 0.5rem 1rem;
        font-weight: 500;
        transition: all 0.2s ease;
    }

    .btn-classic-primary:hover {
        background-color: var(--classic-accent);
        border-color: var(--classic-accent);
        color: white;
        transform: translateY(-1px);
        box-shadow: 0 4px 8px rgba(15, 108, 191, 0.2);
    }

    .btn-classic-secondary {
        background-color: var(--classic-secondary);
        border-color: var(--classic-secondary);
        color: white;
        border-radius: 4px;
        padding: 0.5rem 1rem;
        font-weight: 500;
        transition: all 0.2s ease;
    }

    .btn-classic-secondary:hover {
        background-color: #666666;
        border-color: #666666;
        color: white;
        transform: translateY(-1px);
        box-shadow: 0 4px 8px rgba(102, 102, 102, 0.2);
    }

    /* Card Enhancements */
    .card {
        border: 1px solid #dee2e6;
        border-radius: 6px;
        box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
        transition: all 0.2s ease;
        background: white;
    }

    .card:hover {
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
        transform: translateY(-2px);
    }

    .card-header {
        background-color: var(--classic-light);
        border-bottom: 1px solid #dee2e6;
        font-weight: 600;
        color: var(--classic-dark);
    }

    /* Modal Enhancements */
    .modal-content {
        border-radius: 6px;
        border: none;
        box-shadow: 0 8px 32px rgba(0, 0, 0, 0.15);
    }

    .modal-header {
        background-color: var(--classic-primary);
        color: white;
        border-radius: 6px 6px 0 0;
    }

    .modal-header .btn-close {
        filter: invert(1);
    }

    .modal-title {
        font-weight: 600;
    }

    /* Form Enhancements */
    .form-control:focus {
        border-color: var(--classic-primary);
        box-shadow: 0 0 0 0.2rem rgba(15, 108, 191, 0.25);
    }

    .form-select:focus {
        border-color: var(--classic-primary);
        box-shadow: 0 0 0 0.2rem rgba(15, 108, 191, 0.25);
    }

    /* Alert Enhancements */
    .alert {
        border-radius: 6px;
        border: none;
    }

    .alert-primary {
        background-color: rgba(15, 108, 191, 0.1);
        color: var(--classic-primary);
        border-left: 4px solid var(--classic-primary);
    }

    .alert-secondary {
        background-color: rgba(255, 112, 67, 0.1);
        color: var(--classic-secondary);
        border-left: 4px solid var(--classic-secondary);
    }

    /* Navigation Breadcrumb */
    .breadcrumb {
        background-color: var(--classic-light);
        border-radius: 6px;
        padding: 0.75rem 1rem;
    }

    .breadcrumb-item.active {
        color: var(--classic-primary);
        font-weight: 500;
    }

    /* Table Enhancements */
    .table-striped > tbody > tr:nth-of-type(odd) > td,
    .table-striped > tbody > tr:nth-of-type(odd) > th {
        background-color: rgba(46, 46, 46, 0.03);
    }

    .table th {
        background-color: var(--classic-primary);
        color: white;
        border: none;
        font-weight: 600;
    }

    /* Pagination */
    .page-link {
        color: var(--classic-primary);
        border-color: #dee2e6;
    }

    .page-link:hover {
        color: white;
        background-color: var(--classic-primary);
        border-color: var(--classic-primary);
    }

    .page-item.active .page-link {
        background-color: var(--classic-primary);
        border-color: var(--classic-primary);
    }

    /* Progress Bar */
    .progress-bar {
        background-color: var(--classic-primary);
    }

    /* Badge Enhancements */
    .badge.bg-primary {
        background-color: var(--classic-primary) !important;
    }

    .badge.bg-secondary {
        background-color: var(--classic-secondary) !important;
    }

    /* Link Colors */
    a {
        color: var(--classic-primary);
        text-decoration: none;
    }

    a:hover {
        color: var(--classic-accent);
        text-decoration: underline;
    }

    /* Footer */
    .footer {
        background-color: var(--classic-dark);
        color: white;
        margin-top: 3rem;
        padding: 2rem 0;
    }

    /* Dropdown Enhancements */
    .dropdown-menu {
        border: none;
        box-shadow: 0 4px 16px rgba(0, 0, 0, 0.15);
        border-radius: 6px;
    }

    .dropdown-item:hover {
        background-color: var(--classic-light);
        color: var(--classic-primary);
    }
