# EPUBCheck CSS-001: The … property must not be included in…

Source: https://epublab.com/epubcheck/css-001/ (updated 2026-11-03)

EPUBCheck CSS-001 is an error message: “The "…" property must not be included in an EPUB Style Sheet.” The stylesheet uses a property that EPUB does not allow in its style sheets, such as direction or unicode-bidi.

- Official message (EPUBCheck 5.4.0): The "%1$s" property must not be included in an EPUB Style Sheet.
- Default severity: Error

## Typical causes

- CSS copied from the web that sets text direction in the stylesheet.

## How to fix it

- Remove the property. Set text direction with the dir attribute in the XHTML instead.

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