estilocss.css

.margem {
    margin: 40px;
    padding: 40px;
    display: flex;
    justify-content: center;
    
}

fieldset{
    padding: 30px;
    margin: 30px;
}

h2 {
    font-family: 'Courier New', Courier, monospace;
    font-size: 32px;
    text-decoration: underline overline;
    margin: 10px;
    text-align: center;
    
}

.teclas {
    margin: 10px;
    padding: 5px;
    
}

.igual {
    background-color: limegreen;

}

.op{
    background-color: crimson;
}

.c {
    background-color: cornflowerblue;
}

input {
    width: 50px;
    height: 50px;
    font-size: 20px;
    font-family: Verdana, Geneva, Tahoma, sans-serif;
    border-radius: 10px;
    border-style: none;

}

.calculadora {
    width: 380px;
    height: 380px;
    text-align: center;
    border-radius: 2px;
    border: 1px solid;
    box-shadow: 1px 2px 1px 2px black;
}

.mostra{
    border: 2px solid;
    width: 350px;
    border-radius: 20px;
    margin-left: 13px;
}

.visor {
    margin-top: 20px;
    width: 350px;
    border-radius: 20px;
}

footer {
    font-family: 'Courier New', Courier, monospace;
    color: lightslategray;
    text-align: center;
    margin-top: 30px;
}