.calculator {
    max-width: 400px;
    margin: 50px auto;
    padding: 20px;
    border: 1px solid #ccc;
    border-radius: 5px;
    text-align: center;
    font-family: Arial, sans-serif;
}

input, select, button {
    margin: 10px 0;
    padding: 8px;
    width: 100%;
    box-sizing: border-box;
}

button {
    background-color: #4CAF50;
    color: white;
    border: none;
    cursor: pointer;
}

button:hover {
    background-color: #45a049;
}

.resultado {
    margin-top: 20px;
    padding: 10px;
    background-color: #f8f8f8;
    border-radius: 4px;
}