Improve styling on play screen.

[dcallus]

You currently have to scroll down (depending on phone size) to use the play screen correctly and see all the buttons. Stop this from happening by moving stuff up a little and potentially disabling scroll.

Test at different sizes.

Also make it generally a bit nicer to look at, using Mui buttons (instead of standard html buttons) for restart etc, so it looks consistent. Make the buttons nicely laid out, right now stuff has just been placed there.

[dcallus]

Use themes.

Make play buttons etc styled in themes.
Also set fade to drop-out super quick THEN fade in. To avoid seeing result of state refresh. Also maybe fade in as a different colour briefly.

[dcallus]

closing as a style overhaul is coming