* { box-sizing: border-box; }
html, body { width: 100%; height: 100%; margin: 0; overflow: hidden; }
body {
  display: grid;
  place-items: center;
  background: radial-gradient(ellipse at top, #698c78, #304f42);
  font-family: system-ui, sans-serif;
  -webkit-user-select: none;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}
#GameDiv {
  position: relative;
  width: min(100vw, calc(100vh * 390 / 844));
  height: min(100vh, calc(100vw * 844 / 390));
  width: min(100vw, calc(100dvh * 390 / 844));
  height: min(100dvh, calc(100vw * 844 / 390));
  box-shadow: 0 0 60px #17382966;
}
#Cocos3dGameContainer, #GameCanvas { width: 100%; height: 100%; outline: none; }
canvas { display: block; touch-action: none; }