html {
    
    background: url(assets/stars.jpg) no-repeat center center fixed;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
}

body {
    margin: 0;
    overflow: hidden;
}

div {
    position: absolute;
    top: 40%;
    left:45%;
    width:80px;
}

input {
    width:100px; /*same as the height*/
    height:100px; /*same as the width*/
    background-color:#ff0000;
    border:1px solid #ff0000; /*same colour as the background*/
    color:#fff;
    font-size:1.6em;
    /*set the border-radius at half the size of the width and height*/
    -webkit-border-radius: 50px;
    -moz-border-radius: 50px;
    border-radius: 50px;
    /*give the button a small drop shadow*/
    -webkit-box-shadow: 0 0 10px rgba(0,0,0, .75);
    -moz-box-shadow: 0 0 10px rgba(0,0,0, .75);
    box-shadow: 2px 2px 15px rgba(0,0,0, .75);
}

canvas {
    width: 100% !important;
    height: 100vh !important;
    float: right
}