We've been having some issues with the browser-based version, not sure how to fix that on the game side yet. If it opens in a separate window for your browser, try minimizing that window and then maximizing it again. For some reason, that has worked to fix the issue with a couple of different browsers although I'm not sure if it will fix the issue on safari. Fullscreening the game may help too but I haven't had an opportunity to test it in Safari as much. Not sure why it is doing that in general, one of the weirdest issues I've encountered with a browser-based version