Styling access restricted messages – feature request

Hello,
CUrrently if we restrict a page or block and the restriction action is Show Global Message or Show Custom Message, the “access restricted” message gets shown as a <p> element with no class assignment.
I would like to make these messages show in a special color and perhaps other style settings, so having them displayed with either a UM-standard ID or class in the html, or providing a user setting to set an ID or class would be great.
Thank you for this plugin, the extensions, and the continual improvements.
Kathy