body {
    transition: background-color 0.3s, color 0.3s;
}

.light-mode {
    background-color: #f8f9fa;
    color: #212529;
}

.dark-mode {
    background-color: #212529;
    color: #f8f9fa;
}

.btn-container {
    margin-top: 30px;
}