"simulated browser frame" overlaps the controls on very wide screens

[mfranzke]

• Open https://db-ui.github.io/theme-builder/main/ on a very wide screen
• You'll recognize, that the "simulated browser frame" overlaps the controls, compare to the following screenshot:

[gylxan]

Also have this problem on my machine, which is pretty annoying, because you have zoom out at first steps.

People might oversee this button, when they have wide screen sizes.

My screen size is 2560x1440