Option needed to remove Ugly ‘Borders’ around controls

Hi,
As the title suggests – there seems to be no admin option to remove the ugly black thick borders around the [ZOOM] and [STOP/START SLIDESHOW] controls. there are options to control most other css stylings in admin; so i should imagine it can be implemented quite easily, yes?? Ive tried adding custom overrides to the css file but the changes never stick – could it be because you have used LESS/SASS MIXINS etc so the preprocessing is not being cached with other cache resources.

see screenshot here

Thanks