Thanks for replying.
Since I made my post, I had realised that all the CSS that needs changing is in that file.
The only thing that I managed to change was the colour of some of the text in the header to black and the background to white, but I couldn't figure out how to change the 'Log in or Register' colour.
And that is about as far as I got.
I don't mind editing the file, but it's a matter of what it is that I'm looking for. I have never managed to quite figure out how to use the inspector tool. Also, the link to the Chrome one on that page you guided me to is a broken link.
I'm not sure if that CSS extension will help, because I don't know nearly enough about writing CSS coding.
Basically, I think I just need a nice guide to show me the relevant parts to edit and the absolute most important thing at the moment is hiding those icons in the drop down menu.
I might take a look at some of those templates although I was trying to not spend extra money just yet.