Font colours/colorsFont colours/colors
You can change font colours and font sizes the best way to do this is look for the .css file and edit it in there.
i wont go though what each one does as i feel the guide inside .css explains this very well.
Now where to add things.
If you have a script and wish to add it so it appears on all pages you should enter your script in either overall_header.tpl or overall_footer.tpl
If you wish your script to appear on the main page only then you should enter the code in index.tpl
You can also read my guide on this HERE