Post Title CSS Customization Not Working

Thanks @abdelrhman7, that helped.

So the problem is you’re using a different theme. OP is using the Cards Compact theme -as previously pointed out- and you’re using the Cardview theme. So, of course, the code I shared with the OP won’t apply to you.

You need to change the if condition in the code so it checks for the cardview theme name instead of cards-compact. That’s why I was asking you which is the theme you’re using 😛

Anyways, this is what I’m talking about:

/**
 * Adds CSS rules to the Cards Compact theme.
 *
 * @param  string $additional_styles
 * @param  string $theme_name
 * @return string
 */
function wpp_additional_css_rules($additional_styles, $theme_name){
    if ( 'cardview' == $theme_name ) {
        $additional_styles .= '.wpp-post-title { font-family: sstlight!important; font-size: 14px!important; color: #202224!important; text-decoration: none!important; text-align: start!important; line-height: 22px!important; font-weight: 700!important; } ';
    }
    return $additional_styles;
}
add_filter('wpp_additional_theme_styles', 'wpp_additional_css_rules', 10, 2);

If you’re using a caching plugin don’t forget to flush its cache before testing this code.

Yes, adding the code to your theme’s functions.php file should do the trick.