Also, don't use the file extension for the font-family name. It shouldn't really matter what you use, but it must match --
exactly -- the font-family name of the paragraph class you're trying to assign it to.
You're using:
Code:
font-family:"NotoSansSymbols2-Regular.ttf"
for the @font-face statement, and:
Code:
font-family:"NotoSansSymbols2-Regular"
for the CClock class.
Use:
Code:
font-family:"NotoSansSymbols2-Regular"
for both.
Your src url is fine (as long as the fonts have actually been added to the Sigil epub).