[phossler]

I have several 'Font' folders with a CSS and the fonts that go with it. Some are for different appearances, but some are for special purposes

I just 'Import files' (all of them in the folder) into the epub and link the stylesheets

/* ----------------------------------------------*/
/* Style sheet to use Bookerly fonts ------------*/
/* ----------------------------------------------*/
@font-face {
  font-family: "Bookerly";
  font-weight: normal;
  font-style: normal;
  src: url(../fonts/Bookerly-Regular.ttf);
}
@font-face {
  font-family: "Bookerly";
  font-weight: bold;
  font-style: normal;
  src: url(../fonts/Bookerly-Bold.ttf);
}
@font-face {
  font-family: "Bookerly";
  font-weight: normal;
  font-style: italic;
  src: url(../fonts/Bookerly-RegularItalic.ttf);
}
@font-face {
  font-family: "Bookerly";
  font-weight: bold;
  font-style: italic;
  src: url(../fonts/Bookerly-BoldItalic.ttf);
}
body {
  font-family: "Bookerly";
}