@benoit73 magic mirror has a border defined around the screen
it is defined in css/main.css
--gap-body-top: 60px;
--gap-body-right: 60px;
--gap-body-bottom: 60px;
--gap-body-left: 60px;
you can override this in custom.css
see https://forum.magicmirror.builders/post/2053