[2.x] add html code for only one category

My b2evolution Version: 2.x

I want to display some html code (some formating texts) for only one category ?
Do you know how can I add it ?
I'm using evopress skin.

Try this

global $cat;

if( $cat == 3 )
    echo 'HTML code goes here';

Thanks, I add the code in posts.main.php under
--- END OF REQUEST TITLE ---

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