fix colors and fonts in CSS default styles

[tonifisler]

We have to make sure to never override the styles at all. I spent hours working on some components only to realise now that the styleguide overrides the font with the system one. Ok the font of the project is similar, but still really annoying.

[tonifisler]

In short: never use any of these:

https://stackoverflow.com/a/5612360/1722653

[dmrty]

I am using this PR. there is indeed some bleeding from Toolbox CSS to the component css.
The proposed commit works on my side. I've forked toolbox reader to apply it.

@tonifisler do you want me to create the associated issue ?

[tonifisler]

Thanks @dmrty! @Yago is working on general improvements and will create a release in the near future.

We should maybe release a hotfix with this however, this is currently breaking all our styleguides... :/