body {
    font-family: 'Arial', sans-serif;
    margin: 0;
    padding: 20px;
    transition: background-color 0.5s, color 0.5s;
}

.container {
    max-width: 600px;
    margin: auto;
    background: #fff;
    border-radius: 10px;
    padding: 20px;
    box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
}

button {
    margin: 5px;
    padding: 10px 15px;
    cursor: pointer;
    border: none;
    border-radius: 5px;
}

#output {
    background: #f7f7f7;
    padding: 15px;
    border-radius: 5px;
    min-height: 50px;
}

.light {
    background-color: #f9f9f9;
    color: #000;
}

.dark {
    background-color: #121212;
    color: #fff;
}

button:hover {
    opacity: 0.9;
}