Hi,
The example I've given you is for a select (a normal dropdown).
But on your URL I can see that you have activated the "use chosen library" setting of the Hikashop configuration (or your template adds chosen automatically).
In that case, the selects are transformed into improved HTML elements with javascript when the page is being loaded.
So the CSS I gave you won't work in that case.
You need to adapt it to the HTML elements of chosen, or deactivate chosen.
If you look at the HTML there, you can see:
monosnap.com/file/iKkExYX5hPjmOaK1h3CGc1dFDH5Ijt
So the CSS should be instead:
li[data-option-array-index="0"]{ font-family : "Agency FB";}