a couple of css things

[mattlub]

A couple of points/ideas

• I think the css could be split into multiple files, and potentially matched to the specific components.
• And some of the class names e.g. main-left-div, main-right-div are problematic (they might clash with future html elements, and they are not clear semantically)

I would recommend choosing a certain strategy (e.g. BEM) and trying to stick to it (and document it?!), because imagine if someone had to take over the project and try to continue with the CSS 😁