Drop down menu background size

Hi there,

I was hoping you could point me in the right direction for the CSS code to adjust the background of the drop down menu?

My main issue is that with the 'Accommodation' item in the screenshot below the background box is slightly larger than the rest. Is there any way I can get the whole menu to adjust to the larger size?

I've tried poking around in the CSS but with drop-down menus and hover-overs it's often hard to isolate the correct section to edit.