Add expandable web UI windows

[g-r-a-n-t]

No description provided.

[cburgdorf]

To make this more visual here:

and expanded

I'm generally fine with that solution. I'm not sure if the + sign is the best fit but I also don't know what else would fit the C64 scheme better. In any case I would like to hear what our artist says because I don't care too much about visuals and I think @micahscopes might have a stronger opinion which I don't want to ignore by just merging this.

[micahscopes]

Well, personally my preference would be to lean on tweaking the responsiveness configuration for primary usability and then keep the expanded view as something cute and fun. Most people's attention budgets are too friction-avoidant to figure this all out.

I really think we should do a pass making single column scrolling the default for all but very large screens, and tweaking the media queries accordingly.