body {
    background-color: #f4f4f4;
    font-family: Arial, sans-serif;
    padding: 20px;
}

#calculadora {
    width: 240px;
    margin: 0 auto;
    background: white;
    padding: 10px;
    border-radius: 10px;
    box-shadow: 0 0 10px #aaa;
}

#pantalla {
    height: 50px;
    background: #eee;
    margin-bottom: 10px;
    padding: 10px;
    font-size: 24px;
    text-align: right;
    border-radius: 5px;
}

#botones {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 5px;
}

button {
    padding: 15px;
    font-size: 18px;
    border: none;
    background: #ddd;
    border-radius: 5px;
    cursor: pointer;
}

#botonIgual {
    padding: 15px;
    font-size: 18px;
    border: none;
    background: #18e370;
    border-radius: 5px;
    cursor: pointer;

    grid-column: span 4;   /* Para hacer que ocupe las 4 columnas de botones */
}

button:hover {
    background: #ccc;
}