Add light theme option

[tziporaziegler]

Hopefully this covers all the elements. You may need to change the dark/light option checkbox to an element like a toggle switch to ensure a person does not check both boxes.

Completes Issue #9

[makyen]

I was just writing a comment in the issue thread. I'll take a look at this and see what I can use. I know it was a lot of work. I'm sorry that I didn't see your note as soon as you wrote it.