PriceTable – background blue going to white on mobile devices

Hi there,

I like this plugin very much!

I’ve a small problem with a plugin; pricetable.
I costumize (CSS from the plugin) the button from the pricetable plugin to blue(background) and the font to white. But when I test on my iPhone or iPad I see that the button from the background going totally to white, no blue background.

I try everything to resolve this, but I can’t make it out.

How can I resolve this? Can you give me a suggestion or a advice?

Thanks in advance!

Sincerly,
Bas