So to have it in the same folder:
@font-face {
font-family: my-font;
src: url("my-font.otf");
}
And I can do multiple fonts this way, I suppose, by repeating this with different files?
And if I am now interpreting his answer right, to package it means I need to put the html and font file in a zip file, and treat the zip file as the game file? I shall try that on Itch.io. Ah, it says there has to be an index.html file in the zip file; where do I get that? Or is it actually not always necessary?