# EPUBCheck CSS-007: Font-face reference … refers to…

Source: https://epublab.com/epubcheck/css-007/ (updated 2026-11-03)

EPUBCheck CSS-007 is an info message: “Font-face reference "…" refers to non-standard font type "…".” An @font-face rule points to a font in a format EPUB does not list as a core font type.

- Official message (EPUBCheck 5.4.0): Font-face reference "%1$s" refers to non-standard font type "%2$s".
- Default severity: Info

## Typical causes

- Fonts in formats other than TrueType, OpenType, WOFF or WOFF2.

## How to fix it

- Convert the font to WOFF2, WOFF, OpenType or TrueType, or remove the @font-face rule.

Message text and severity: EPUBCheck (W3C, BSD-3-Clause). Explanation: EPUBLab.