html {
  box-sizing: border-box;
}
*, *::before, *::after {
  box-sizing: inherit;
}
html, body {
    margin: 0;
    padding: 0;
    position: relative;
    background: #000;
}
#game {
  margin: 0;
  padding: 0;
  width: 960px;
  height: 540px;
  position: absolute;
  top: 50%;
  left: 50%;
  margin: 42px 0 0 -480px;
}