Rename CSS Vars to something more semantic

[ryansegus]

Hello, nice job on the carousel, one little thing tough, I noticed that you have --carousel-color-white this can be easily change to something more meaningful, I propose --carousel-color-arrows.

In my case I wanted the arrows red with a background white so the naming looks weird:

--carousel-color-white: red; // This makes no sense
--carousel-color-arrows: red; // Better :)

I tried to push on your repository but I wasn't able, anyhow there just three changes:

examples.md
navigation.css
variables.css

Cheers!

[ismail9k]

Good idea actually, I will try to implement it.