body{
background-image:url(../img/fondo.jpg);
background-size: cover;

}
.A{
    border: black solid 5px;
    border-top-left-radius: 30px;
    border-top-right-radius: 30px;
    border-bottom-right-radius: 30px;
    border-bottom-left-radius: 30px;
    background-color: blue;
    color: white;
    text-align: center;
    margin-left:20px;
    width:45%;
}

.A:hover {
    background-color: lightblue;
}

.B{
    border: grey solid 5px;
    border-top-left-radius: 20px;
    border-top-right-radius: 20px;
    border-bottom-right-radius: 20px;
    border-bottom-left-radius: 20px;
    background-color: black;
    color: grey;
    text-align: center;
    margin-left:20px;
    margin-top:20px;
    width:35%;
}

.B:hover {
    background-color: lightcoral;
}

.C{
    border: black solid 5px;
    background-color: grey;
    color: black;
    text-align: center;
    margin-left:20px;
    margin-top:20px;
    width:25%;
}

.C:hover {
    background-color: green;
}