Previously it was possible to choose a color combination
that was almost impossible to read (due to contrast).
Now we have prevented this from happening, as well as
giving the user more customizability.
This way reacts better to changing the screen sizes.
I think there was one bug where the fab wouldn't be
precisely at the bottom of the page depending on the
flat list length.
This makes the button automatically adjust
according to what the user has set the primary
color to be.
Seems that with the default dark theme the cyan
makes the text not the same color as the Button,
but this still looks better than the statically
set colors from before.