* {
  -moz-box-sizing: content-box; /* or `border-box` */
  -webkit-box-sizing: content-box;
  box-sizing: content-box;
}
body {
  font-family: Arial, sans-serif;
  background: linear-gradient(0deg, rgba(0,0,0,1) 0%, rgba(50,50,50,1) 100%);
  color: #fff;
  margin: 0px;
  overflow: hidden;
  cursor: crosshair;
}
canvas {
  position: absolute;
  width: 100%;
  height: 100%
}