When setting the banner change description, the field performs a little

jump, first shrinking to accomodate all text and then expanding

slightly. This is because the margin on a part of the banner was being

applied to the text, creating a little bit of extra space at the bottom

of the field.
This change tightens up the CSS to only apply the styling to the correct

parts of the banner, fixing this visual issue.

Tested clearing the field, saving, entering new text, and saving. There

was no longer a visual jump in the field. It instead maintained the

correct size.