body{
background-image: url(http://hdqwalls.com/wallpapers/glitch-art-4k-wl.jpg);
background-repeat: no-repeat;
}

button.dreta{
margin-right: 0;
right: 0px;
float: right;
clear: left;
}

button.esquerra{
margin-left: 0;
left: 0px;
float: left;
clear: left;
}

footer{
margin-right: 0;
bottom: 200px;
right: 0px;
float: right;
clear: right;
color: white;
}