dillon1000/react

[Playground] Style compiler options editor

This diff adds styling to the compiler options editor. The floating input/output 
toggle button on small screens now spans the bottom of the screen, so that it 
doesn't block the compiler options. 

Height overflows when adjusting screen size are complicated by Monaco Editor and 
will be addressed in a later diff. 

Test plan: 

Start Playground and see the latest look of the compiler options editor beneath 
the output section.