body {
    -webkit-transform: translate3d(0,0,0);
    background-color: #ffffff;
    font-family: 'Courier';
    -moz-background-size: cover;
    -webkit-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
    height: 100%;
}

html {
    height: 100%;
}

canvas {
    -webkit-transform: translate3d(0,0,0);
    -webkit-tap-highlight-color: rgba(0,0,0,0);
}

.centered {
    //You can use just margin:auto; or both left and right margin auto :)
    margin-left: auto;
    margin-right: auto;
    width:70%;
}