index.css

html {
  -ms-touch-action: none;
}

body, canvas, div {
  margin: 0;
  padding: 0;
  outline: none;
  -moz-user-select: none;
  -webkit-user-select: none;
  -ms-user-select: none;
  -khtml-user-select: none;
  -webkit-tap-highlight-color: rgba(0, 0, 0, 0);
}

body {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  padding: 0;
  border: 0;
  margin: 0;

  cursor: default;
  color: #888;
  background-color: #333;

  text-align: center;
  font-family: Helvetica, Verdana, Arial, sans-serif;

  display: flex;
  flex-direction: column;
}

#Cocos2dGameContainer {
  position: absolute;
  margin: 0;
  overflow: hidden;
  left: 0px;
  top: 0px;

  display: -webkit-box;
  -webkit-box-orient: horizontal;
  -webkit-box-align: center;
  -webkit-box-pack: center;
}

canvas {
  background-color: rgba(0, 0, 0, 0);
}