Spartan MB font looking weird on buttons, Safari Mac

Site URL: https://www.ditbaderum.dk/

Hi guys,

So I have this custom font on my site using @font-face. However, it looks bad on buttons only... as if it does not work on it.

Any suggestions for a solution? I know another site for which it works completely fine.

Thank you for your time and have a nice day.

I fixed it. Just made the letter-spacing -0.5px on @media screen max 767px