Improve button states for joined/paid

[jancborchardt]

The dark/light button states are not fully clear. We could improve them by using red for »joined« (cause it puts you in the red ;) and green for »paid« (as green is also a »money« color). We could additionally use icons such as a coin/moneybag for »paid« and something like a checkmark for »joined«.

Then we should also remove the checkmark from the »all joined« button to not distract too much.

[jancborchardt]

The color and symbol solution is a bit confusing. But what we could do is make the selection elements only outlined/have a border, and the selected one being filled.

[jancborchardt]

Another nice way would be to swap the "paid" and "joined" so "paid" would be on the left. Then on pressing "paid" it wouldn’t have to switch around like it currently does, but only convert the "joined" part into a text field: