body {
    background: linear-gradient(to right, #000000, #000000c9, #060f25);
    transition: background-color 0.3s, color 0.3s;
}

h1, h3 {
    color: #ffffff;
    transition: color 0.3s;
}

.alert {
    font-size: 1.2rem;
}

.btn-primary, .btn-success {
    font-size: 1rem;
    padding: 10px 20px;
}

.dark-mode {
    background-color: #2c3e50;
    color: #ffffff;
}

.dark-mode h1, .dark-mode h3 {
    color: #ffffff;
}