How can I get the same style I have on desktop to show up on mobile?

I have a couple of buttons I have styled that look great on the desktop view.. but they are way off on the mobile view..

how do I use @media screen to show the style correctly?

the buttons I am talking about are:

the REGISTRO on homepage here mindfulscience.es
and the submit button here https://www.mindfulscience.es/registro/

not sure how to get those to display correctly on mobile.

thanks advance for any direction on this..

cheers,

EJ