# RSC-013: fragment on a stylesheet link, how to fix it

Source: https://epubcc.com/epubcheck/rsc-013/ (updated 2026-11-04)

EPUBCheck RSC-013 is a usage message: “Fragment identifier is used in a reference to a stylesheet resource.” A reference to a stylesheet includes a fragment identifier (#part), which has no meaning for CSS files. It is a usage message: the stylesheet still loads, the fragment is just ignored.

- Official message (EPUBCheck 5.4.0): Fragment identifier is used in a reference to a stylesheet resource.
- Default severity: Usage

## Typical causes

- A link element with an href such as style.css#main.
- A build tool that appends fragments or cache markers to resource URLs.

## How to fix it

1. Find the link element named in the message.
2. Remove the #fragment from the stylesheet reference, for example href="style.css".
3. If a build step adds it, change the step so the next build is clean.

## When it's not this

A query string (?v=2) in a relative URL is a different error, RSC-033.

## Sources

- EPUB 3.3, §4.2.5 URLs in the OCF abstract container: https://www.w3.org/TR/epub-33/#sec-container-iri (read 2026-11-04)

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