XF 1.3 How to change the number of forums on the same line?

By default there is one.
How do I increase the number? I'd like to have 2 or 3.
For example if I have 12 forums under the same category, they are all listed one by one below the category - 12 'lines'.
If I wanted three forums on the same lines, there would be only 4 lines.
Where can I edit that? I've seen other forum having 2 or 3, even by category.

Lukas W.

Formerly katsulynx
Basically you can do this for a two-column list:
.category .nodeList > li {
width: 50%;
display: inline-block;
or this for a three-column list:
.category .nodeList > li {
width: 33.3%;
display: inline-block;
However, it's just the basic and will require additional styling of children elements.