# EPUBCheck CSS-003: CSS document is encoded in UTF-16. It…

Source: https://epublab.com/epubcheck/css-003/ (updated 2026-11-03)

EPUBCheck CSS-003 is a warning message: “CSS document is encoded in UTF-16. It should be encoded in UTF-8 instead.” A CSS file is encoded in UTF-16; UTF-8 is recommended.

- Official message (EPUBCheck 5.4.0): CSS document is encoded in UTF-16. It should be encoded in UTF-8 instead.
- Default severity: Warning

## Typical causes

- A stylesheet saved in UTF-16 by an editor.

## How to fix it

- Re-save the file as UTF-8, and change any @charset rule to "UTF-8".

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