Hi. I would like to change the topic's entry contents codes (.pun .entry-content) in some categories like "news" etc but in rest categories to be normal-default settigs.
Can we do that?

Hello J0k3R^,

See if this works :
Administration Panel > Modules > JavaScript codes management > Create a new script

Title : Your choice
Placement : In the topics
Paste the code below :

Code:

$(function() { if (!$('.nav').length) return;
  catPost(1, 'category1');
  catPost(2, 'category2');
  
  function catPost(category, name) {if (Number($('a.nav[href^="/c"]:first').attr('href').replace(/\/c(\d+)-.*/,'$1')) == category) $('.post').addClass(name)}
});

To set a class for posts in a certain category simply copy and paste catPost('category', 'name'); in the script above.

category : This is the category ID that you want the script to take effect in. You can see it from the URL : fmplanet.forumgreek.com/c1-category

name : This is the classname you want to add to posts, so you can style them via your CSS stylesheet.

For example if I give the posts the class of 'category1' I could do something like this in my stylesheet :

Code:

.post.category1 .postbody {
  background:red
}

Hm i followed everything u said but i didnt see the background to be red in 1st category. 
To make it more specific, i'd like to affect the /f5-forum and /f6-forum instead.

Replace your script with this :

Code:

$(function() { if (!$('.nav').length) return;
  catPost(5, 'forum5');
  catPost(6, 'forum6');
 
  function catPost(category, name) {if (Number($('a.nav[href^="/f"]:first').attr('href').replace(/\/f(\d+)-.*/,'$1')) == category) $('.post').addClass(name)}
});

Hm okey now its working but my settings affect more things (Likes + Edit).
Is it possible to declare something or do any other changes so only the topic's text will be affected?

Have you tried .post.forum5 .entry-content div div ?

nice
one more thing? if we could make it change style only for 1st post of the topics?

See if this works :

Code:

.post.forum5:first-child .entry-content div div

didnt work