[Plugin] CSSValidator - Offline W3C CSS Validator

[KevinH]

Jon, please stop attacking everything that is epub3. CSS3 is valid in epub3 and rem is different than em in epubs that use different font sizes in different places as it always references the size of the font in the root (html) element.

Epub2 is now totally dead. Deprecated almost 15 years ago (first approved epub3 spec was dated, October 11, 2011). Nothing new should ever be created in epub2.

Good, spec compliant Epub3 readers are now broadly available and making epub3 backwards compatible with the old epub2 spec is possible.

This forum's love and support for a long dead specification is really misguided.

Fair warning: At some point, Sigil will eventually drop support for creating new epub2s and when asked to load one, it will eventually use integrated code (based in my ePub3-itizer plugin) to generate an epub3-only version for editing and saving.

[Doitsu]

Originally Posted by hayaku

IE, unit : “rem” is an incorrect unit : padding: 0.25rem; when I have a CSS entry like "padding: 0.25rem;".

As KevinH has already pointed out, you'll only get this message when CSS2.1 (or lower) is selected as the CSS spec.
You can test this yourself with the online validator:
https://jigsaw.w3.org/css-validator/

If you're working on epub3 books, you'll need to change the following plugin preferences:

  "css_epub2_validation_spec": "css21",
  "css_epub3_validation_spec": "css3",

For more information, see the very first topic.

[JSWolf]

Originally Posted by KevinH

Jon, please stop attacking everything that is epub3. CSS3 is valid in epub3 and rem is different than em in epubs that use different font sizes in different places as it always references the size of the font in the root (html) element.

Epub2 is now totally dead. Deprecated almost 15 years ago (first approved epub3 spec was dated, October 11, 2011). Nothing new should ever be created in epub2.

Good, spec compliant Epub3 readers are now broadly available and making epub3 backwards compatible with the old epub2 spec is possible.

This forum's love and support for a long dead specification is really misguided.

Fair warning: At some point, Sigil will eventually drop support for creating new epub2s and when asked to load one, it will eventually use integrated code (based in my ePub3-itizer plugin) to generate an epub3-only version for editing and saving.

If you are creating an ePub for sale, it could get read on a Kobo as ePub and ref will not work. It could get read on a nook or an old Sony Reader where rem does not work.

So if you want to make sure you eBook does not break us em.