A set of reference stylesheets for EPUB Reading Systems.
Readium CSS provides styles for reflowable text:
- paged and scrolled views;
- a “patch” for HTML5 Suggested Rendering specific to publications (e.g. extra styles for hyphenation, breaks, etc.);
- default styles for unstyled ebooks;
- theming;
- user settings;
- a set of baselines and recommendations for accessibility, overrides, and internationalization.
BSD-3-Clause (http://opensource.org/licenses/BSD-3-Clause)
See license.txt.
The primary goal of Readium CSS is to provide Reading System implementers with reliable and modern styles for reflowable EPUB 2 and EPUB 3 files. In addition, it should provide good interoperability in the existing ecosystem, while not overriding authors’ styles unless strictly necessary.
Readium CSS stylesheets were not designed and should not be used for fixed-layout EPUB, nor other file formats like FB2, PRC, Mobi, TEI, etc.
Some issues, which may be raised during development, will be documented so that they can serve as a reference for revisions of the EPUB specification, and even future specifications.
Readium CSS is implemented in the Readium Mobile and Readium Web projects.
You will find it in:
External use include:
Active development is pulled in branch develop.
Building and testing are relying on npm packages and scripts. To initialize your clone/fork, first install dev dependencies:
npm install
In case you’re encountering an error with Puppeteer, make sure you’re using at least Node v.20.11.1 – it might work with an earlier version but only the latest LTS as of March 21, 2024 has been tested.
Then create reference bitmaps for visual regression testing:
npm run test:ref
To transpile all stylesheets using PostCSS:
npm run build
To test the updated styles and catch visual regression bugs:
npm run test
To update reference bitmaps after a bugfix:
npm run test:approve
Documentation can be accessed in docs.