body {
    font-family: 'Arial', sans-serif;
    margin: 0;
    padding: 20px;
    text-align: center;
}

#atm {
    border: 1px solid #333;
    padding: 20px;
    width: 300px;
    margin: auto;
}

.screen {
    border: 2px solid #666;
    padding: 10px;
    margin-bottom: 20px;
    height: 100px;
    color: #fff;
    background-color: #000;
}

input, button {
    margin-top: 10px;
}