body {
    background-color: #f8f9fa;
}

.card {
    box-shadow: 0 0.125rem 0.25rem rgba(0, 0, 0, 0.075);
    margin-bottom: 1rem;
}

.card-header {
    font-weight: bold;
}

.table th {
    background-color: #f8f9fa;
}

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

.btn-lg {
    padding: 0.75rem 2rem;
    font-size: 1.25rem;
}

#duration {
    font-size: 2rem;
    font-weight: bold;
    color: #007bff;
}

.alert {
    margin-bottom: 1rem;
}

.badge {
    font-size: 0.8rem;
}

@media (max-width: 768px) {
    .btn-lg {
        width: 100%;
        margin-bottom: 0.5rem;
    }
    
    .table {
        font-size: 0.85rem;
    }
}