:root {
    --primary-color: #0d6efd;
    --secondary-color: #6c757d;
    --success-color: #198754;
    --info-color: #0dcaf0;
    --warning-color: #ffc107;
    --danger-color: #dc3545;
    --light-color: #f8f9fa;
    --dark-color: #212529;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: #f5f5f5;
}

.navbar-brand {
    font-weight: 600;
}

.card {
    border: none;
    box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    transition: box-shadow 0.3s ease;
}

.card:hover {
    box-shadow: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
}

.table-responsive {
    border-radius: 0.375rem;
}

.badge {
    padding: 0.35em 0.65em;
    font-weight: 500;
}

.btn {
    font-weight: 500;
    transition: all 0.2s ease;
}

.btn:hover {
    transform: translateY(-1px);
}

.form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.2rem rgba(13, 110, 253, 0.25);
}

.list-selection {
    background-color: white;
}

.list-selection .form-check {
    padding: 0.5rem;
    margin: 0;
    border-bottom: 1px solid #eee;
}

.list-selection .form-check:last-child {
    border-bottom: none;
}

.list-selection .form-check:hover {
    background-color: var(--light-color);
}

.thread-container {
    max-width: 900px;
    margin: 0 auto;
}

.message-card {
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.alert {
    border: none;
    border-radius: 0.5rem;
}

.dropdown-menu {
    border: none;
    box-shadow: 0 0.5rem 1rem rgba(0, 0, 0, 0.15);
}

@media (max-width: 768px) {
    .container-fluid {
        padding: 0 1rem;
    }
    
    .card-body {
        padding: 1rem;
    }
    
    .table {
        font-size: 0.875rem;
    }
}