The css directives here are probably a part of the answer: https://github.com/oklemenz/PrinceJS/blob/master/assets/web/game.css https://github.com/oklemenz/Pri

The css directives here are probably a part of the answer: https://github.com/oklemenz/PrinceJS/blob/master/assets/web/game.css https://github.com/oklemenz/PrinceJS/blob/master/assets/web/... And also see the <meta name="viewport" ... values in the page itself.