*{
    margin: 0;
    padding: 0;
}
body{
    padding: 30px; 
    background: url('https://wallpaperaccess.com/full/1906529.jpg') no-repeat center center fixed; 
    -webkit-background-size: cover;
    -moz-background-size: cover;
     -o-background-size: cover;
    background-size: cover;
}
.Keys{
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 90vh;
}
.key{
    width: 70px;
    height: 70px;
    text-align: center;
    background: rgba(0, 0, 0, .6);
    padding: 5px;
    border-radius: 4px;
    color: white;
    transition: 0.5s;
}
.sound{
    display: block;
    margin: 3px 0;
}
kbd{
    margin: 3px;
    display: block;
}

.key-css{
    background: rgb(0, 0, 0);
    box-shadow: 
                0 0 10px white,
                0 0 15px white
                ;
}