The easiest way is to embed it, you will have to ask in the Kobo forum for instructions on sideloading fonts.
The important thing is that the
CSS is instructing the renderer to use your font.
The last we heard, your CSS still said (the OP):
Code:
.calibre {
display: block;
font-family: "Calibri", serif;
font-size: 1.25em;
padding-left: 0;
padding-right: 0;
margin: 0 3pt
}
Did you ever get around to switching the font-family to "font-family: sans-serif;"
If, for some reason, you absolutely positively must have some specific instantiation of a sans-serif font, did you embed it using the Manage Fonts tool,
as well as specifying that font-family in the CSS?
Note: You will need to match the font-face rule.
Note2: I feel it would be instructive to reference the friendly guide to CSS at W3Schools:
CSS font-family property