html {
    overflow: hidden;
    -ms-touch-action: none;
    -ms-content-zooming: none;
}
body {
    position: absolute;
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    background-color: #fff;
}
.canvas-box {
    width: 100%;
    height: 100%;
    position: relative;
}
.canvas-box:before {
    width: 100%;
    height: 100%;
    content: ' ';
    position: absolute;
    background-image: url("../imgs/bg.jpg");
    background-repeat: no-repeat;
    background-size: 200% 150%;
    background-position: center bottom;
    opacity: .5;
}
#canvas {
    position: absolute;
    width: 100%;
    height: 100%;
    /*background-color: #fff;*/
}