Build a repository of braille CSS style sheets

[bertfrees]

Pipeline doesn't have any braille formatting defaults. Braille transcription is not an issue, as we rely on the Liblouis library, which supports many languages (thanks to its wide use and large community). But braille formatting is done in Pipeline itself based on CSS, and we currently don't provide style sheets for the whole world. Note that there is no global braille formatting standard.

We don't have the ambition nor the resources to look up all the different braille formatting standards that exist and implement a style sheet for each of them ourselves. But on the other hand, having good defaults is crucial for the usability of Pipeline. So we need help from the DAISY community to build a repository of style sheets.

First, we should have a place that people can find easily and make it easy to contribute stuff. We probably need a few good examples of style sheets to start with. Perhaps a kind of template could be useful too. And a kind of tutorial-style document for creating a braille style sheet. Note that we have the braille CSS reference documentation, but this is not very suited as guidance.

The ebraille initiative should be mentioned also. Since it also relies on CSS for braille formatting, it has a very similar challenge. So this can become a combined effort.

As for the level of sophistication of submitted style sheets: I think it's important to accept anything from basic style sheets to comprehensive ones. Whatever is in the repository can be built on and improved by others. Anything that is too specific to an organisation's content or workflow (such as non-standard classes for instance) should be automatically filtered out with some tool, so that this is not the job of the contributor.

Note also that Pipeline supports Sass, a superset of CSS which can have parameters that the user can set via the Pipeline user interface, but we should not have any requirements regarding parameters that a style sheet should have. Instead, we should make the user interface adapt to the parameters that have been defined in a given style sheet.