CSS "break-before: always" Ignored

Do you mean in a custom style? The PDF/print preview no longer uses WebKit's print system, so is not affected by most webkit CSS rules. That said, it should recognize page-break-before. If you want to share an example document and your custom style, I can test.

It's a custom stylesheet.

To help you debug the issue I'll attach:

1. A screenshot of the first page
2. A screenshot of the style management dialog
3. A screenshot of the Print Preview rendering
4. A snippet of my Markdown file (the whole thing is 344KB)
5. My complete CSS file

The CSS indicates that there should be a page break before each of the H2 headings, such as "Apple Cider-Sage Vinaigrette" and "Apple Crisp".

Cookbook Snippet.md

Cookbook.css

Ok, as I said in another post, the ideal way to deal with this is just to enable "Add page break before h2" in the settings. page-break-before has no effect in Marked 3, but that will do exactly what you want.

At least it will. Before I recommended this to you I ran a test with your document and CSS and discovered some bugs that hadn't come to light with other documents. Those are fixed now and you can expect a working version this week.