I dont know if there's already themes for download. You can make a copy of the default template folder and modify the theme parameter within the systemglobals properties file, so that it will load the correct theme.
YOu have to work with CSS. In most cases you pretty much can figure which value may influence what. It's named quite intuitive I think. If you dont know the functionality of CSS, it of course will be very confusing.
You should get a brief overview of it first, reading some tutorials. Of course you also could read the CSS documentation of w3c ;)
YOu can change about pretty much everything using CSS ... that is in font size, coloring, ...
I've modified the CSS of the forum so that it matches the external portal coloring that it's embedded in.
[originally posted on jforum.net by Sid]