Update main.css for doc styles

[BorisKourt]

Did a pass on the docs, I couldn't read the "options" sections of pages as everything was the same colour.

Also added normalize CSS to smooth out some general issues like horizontal scroll in certain situations.

If there are any issues I can provide further edits and troubleshooting.

Here is the proposed look in this PR:

[oakes]

Looks really good, thanks. The only thing I hesitate on is some of the text coloring. It seems like option names should be blue, since that's how keywords are normally displayed in text editors. Perhaps headers and links should both remain white so they can be neutral and less imposing. What do you think?

Also, can the background for items like :cpy in the screenshot be fixed? It seems to not fill the line if there isn't a description.

[BorisKourt]

I can tone down the colours to just off white in the sidebar, generally it is better if there is at least some differentiation otherwise its hard to focus on any one item.

Ill change the background & colour in the main area. The background is missing because I wanted to de-emphasize areas without a full description but I can see how it could be annoying.

[BorisKourt]

Decided to go with simpler vertical spacing. As with the previous one, args brighten on hover. Toned down the colours in the sidebar and added a clean fade to push it back a bit when reading the main area.

[oakes]

Thanks, it looks really great. I also updated highlight.js and hightlight.css so the keywords are blue in the code blocks as well. The style is now live on the docs site.

[BorisKourt]

Awesome! :) Give me a shout if there are any issues down the line I can do a patch.