Sizing it

The games lay themselves out to whatever rectangle you give them, from a narrow phone column to a wide desktop panel. They are designed portrait first — a tall box flatters every one of them.

A panel in a page

<div style="max-width:420px;margin:0 auto">
  <iframe src="…" style="border:0;width:100%;aspect-ratio:9/16;display:block"></iframe>
</div>

The whole screen

<iframe src="…" style="border:0;width:100%;height:100dvh;display:block"></iframe>

Use 100dvh rather than 100vh: on a phone, vh ignores the browser's own toolbars and pushes the bottom of the game off the screen.

Two rules of thumb

Give it a definite height. An iframe with no height collapses to 150px, and the game will draw itself into that.

Do not scale it with a CSS transform. The game measures its own box to lay the board out and to hit-test taps; a transform makes what it measures and what you see disagree, and taps land on the wrong square.