font warning in epub validator

[carlangel]

Can someone help interpret this validator warning:

"INFO(CSS-007): ./books/Bo/databases/eBookIt/temp_uploads/1590631189.epub/OEBPS/Styles/idGeneratedStyles.css(36,2): Font-face reference OEBPS/Fonts/Antonio-Bold.ttf refers to non-standard font type application/x-font-ttf."

My first guess was maybe it was a font conflict or incompatibility issue, but the same font and css is used throughout the other chapters and they exported fine (no warning messages) so I'm wondering what's going on. The only thing that's different is that this chapter contains a table whose borders I set to 0 in Sigil, but that would be unrelated, right?

Thanks,

Carl

[Laubender · Accepted solution]

Hi Carl,

suffix *.ttf of your used font file points to a TrueType font. That's against EPUB 3 specifications:

"EPUB 3 requires Reading Systems to support the OpenType and WOFF font formats for embedded fonts in conjunction with the CSS @font-face rules."

Source:

http://idpf.org/epub/30/spec/epub30-changes.html#sec-new-changed-embedded-fonts

Regards,
Uwe Laubender

( ACP )