How to make differences in title's posts style

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lilipad.ir

if your theme is using post_class() you can use a filter to insert specific CSS classes for the first three posts, or alternating CSS classes;

https://codex.www.ads-software.com/Function_Reference/post_class#Add_Classes_By_Filters

example:

function special_post_class($classes) {
	    global $wp_query; $this_post = $wp_query->current_post;
	        if( $this_post t == 0 ) $classes[] = 'post_nr_1';
	        if( $this_post  == 1 ) $classes[] = 'post_nr_2';
	        if( $this_post  == 2 ) $classes[] = 'post_nr_3';
	        if( $this_post %2 == 0 ) $classes[] = 'post_odd';
	        if( $this_post %2 == 1 ) $classes[] = 'post_even';
	        return $classes;
	}
	add_filter('post_class', 'special_post_class');

then use CSS for the formastting;
example:
.post_nr_1 .entry-title { color: red; background-color: yellow; }

(untested)

you could also ad some code directly into the template file; please post the full code to get a suggestion; https://codex.www.ads-software.com/Forum_Welcome#Posting_Code