Theme Horse

The theme styles will not control for the backend pages. You have to use the plugin to control for it. Please use this plugin to remove the admin bar.
after installing the plugin go to its setting and paste the below Custom CSS code to Admin CSS field.

html.wp-toolbar {
	padding-top: 0;
}
#wpadminbar {
	display: none;
}

and if you are already using some other plugin to remove the admin bar in backend then please add the below CSS Code to it.

html.wp-toolbar {
	padding-top: 0;
}

Thanks