html {

font-size: 10px;

background:url(http://i.imgur.com/b9r5sEL.jpg) bottom center;

background-size: cover;

body,html {

margin: 0;

padding: 0;

font-family: sans-serif;

.keys {

display:flex;

flex:1;

min-height:100vh;

align-items: center;

justify-content: center;

.key {

border:4px solid black;

border-radius:5px;

margin:1rem;

font-size: 1.5rem;

padding:1rem .5rem;

transition:all .07s;

width:100px;

text-align: center;

color:white;

background:rgba(0,0,0,0.4);

text-shadow:0 0 5px black;

.playing {

transform:scale(1.1);

border-color:#ffc600;

box-shadow: 0 0 10px #ffc600;

kbd {

display: block;

font-size: 40px;

.sound {

font-size: 1.2rem;

text-transform: uppercase;

letter-spacing: 1px;

color:#ffc600;