body {
  font-family: PingFangSC-Regular, Roboto, Helvetica Neue, Helvetica, Tahoma, Arial, PingFang SC-Light, Microsoft YaHei;
  font-size: 12px;
}
body * {
  box-sizing: border-box;
}

body, #app {
  position: fixed;
  left: 0;
  right: 0;
  bottom: 0;
  top: 0;
  box-sizing: border-box;
  padding: 0;
  margin: 0;
  overflow: hidden;
  text-rendering: optimizeLegibility;
  -webkit-user-select: none;
  -webkit-user-drag: none;
  -webkit-text-size-adjust: none;
  -webkit-touch-callout: none;
  -webkit-font-smoothing: antialiased;
}

#engine {
  width: 100%;
  height: 100%;
}