Feature/material design reol 72

Since when did all browser follow the standards? I agree with him, that we should not let it be up to the browser, to decide which color code we are using. And for readability, i believe that anyone who can program CSS knows what #fff and #000 means. 

I agree that all colors should be defined as variables. Defining white/black as variables would also be good imo, just maybe call it something like $light and $dark. This allows small adjustments to the white and black colors throughout the site to be implemented easily.

Why are they supposed to be lower case? I am indifferent, i just haven't heard any pros/cons of either way.