In my current project, section titles are typeset in SansBold while the body text (and that of the ToC) is roman.

How can I define \definehighlight[emph], so that I get SansBoldItalic in titles and SerifItalic in body text and ToC? (Body text is not a problem.)

MNWE:

\setuphead[chapter][page=yes,style={\ss\bfc}]
\setuphead[section][page=no,style={\ss\bfa}]
\definehighlight[emph][style=\it]