[Theme Horse Support Team]

Hi francois.jourjon,

Is this your sitelink ? It seems that you have implement the child theme in a wrong way.
Just add below code inside child theme of style.css

/*
Theme Name: Clean Retina Child
Theme URI: https://www.themehorse.com/themes/clean-retina
Author: Theme Horse
Author URI: https://www.themehorse.com
Version: 2.0.1
Text Domain: cleanretina
Template: clean-retina
*/

@import url("../interface/style.css"); 
.entry-meta .date {
display: none;
}

Did you tried with parent theme whether it works or not? Activate the Parent theme and let us know if there is some issues.

Thank you!