On mobile view my 'continue shopping' button in cart goes black when clicked on

Site URL: https://primo-coffee.co.uk

Hi there, I changed the colour of my secondary button to match the primary button and the 'continue shopping' button on mobile view goes black when clicked on, as you can see below... Looks fine in SS, but just black on my iphone.  Any help would be very much appreciated,

Thank you

All sorted! Panick over