How to have hyphenation without breaking h1, h2...?

[repilo]

How can I enable hyphenation in kepub while ensuring that it respects the CSS rules not to hyphenate headings like h1, h2, etc.?
I convert epub to kepub with Calibre and send them to the Kobo.
With kobopatch I activate “Set KePub hyphenation: yes”.
And yes, I get hyphenation.
The doubt I have is why there are word divisions also in the headers (h1, h2, ...), even though in style.css I have all this:

    adobe-hyphenate: none;
    -ms-hyphens: none;
    -moz-hyphens: none;
    -webkit-hyphens: none;
    -epub-hyphens: none;
    hyphens: none;

The same thing happened to me without activating that patch and activating hyphenation in Calibre during conversion to kepub.