How to change Header button to custom font on Mobile version

Use this code to Custom CSS box. Replace Borna-Hut with the font name that you want.

@font-face {
font-family: 'Borna-Hut';
src: url(paste custom font file url here);
}
.header-menu-cta a.btn {
  font-family:'Borna-Hut' !important;
}