# CSS-015: alternate CSS without title, how to fix it

Source: https://epubcc.com/epubcheck/css-015/ (updated 2026-11-04)

EPUBCheck CSS-015 is an error message: “Alternative style sheets must have a title.” An alternative style sheet has no title attribute. A link with rel="alternate stylesheet" needs a title, because the title is what a reading app shows when offering the alternative style.

- Official message (EPUBCheck 5.4.0): Alternative style sheets must have a title.
- Default severity: Error

## Typical causes

- A link element for an alternate style written without title.
- A night or vertical-writing style added by a tool that left the title out.

## How to fix it

1. Open the file EPUBCheck names (the message gives the path, line and column) in a text or EPUB editor such as Sigil, or unzip the EPUB and open it there.
2. Add a title attribute that names the style, for example <link rel="alternate stylesheet" title="Night" href="night.css" type="text/css"/>.
3. If the stylesheet should always apply, change rel to plain stylesheet instead.
4. Rebuild the EPUB and run EPUBCheck again to confirm the message is gone.

## When it's not this

If the alternate style sheets carry conflicting style tags, see CSS-005.

## Sources

- EPUBCheck 5.4.0 message texts (MessageBundle.properties, w3c/epubcheck on GitHub): https://github.com/w3c/epubcheck/blob/v5.4.0/src/main/resources/com/adobe/epubcheck/messages/MessageBundle.properties (read 2026-11-04)

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