[Masad791]

Description

Fixes #14882.

brandTypographyLayer now runs family values through asCssFont, the same helper the mainfont/monofont path uses, so Source Sans 3 comes out as "Source Sans 3". That's enough for html.

revealjs needed one more step. reveal.js' exposer.scss builds --r-main-font, --r-heading-font and --r-code-font with #{$mainFont} etc., and interpolation drops the quotes again. That also means mainfont: Source Sans 3 is broken in revealjs today, not only the brand path. Rather than edit the vendored file, quarto.scss re-declares those three properties (plus the inline/block code font ones it already sets) with #{inspect(...)}, the way Bootstrap's _root.scss does. Quarto's rules come after the framework rules, so these win. --mermaid-font-family in _quarto-rules.scss had the same interpolation, so it got inspect() too.

Checked in Chromium: body was computing to Times; with this change body, h2 and code compute to "Source Sans 3", "Bricolage Grotesque 96pt" and "M PLUS 1 Code" in both html and revealjs.

Tests: 2026/10/19/issue-14882.qmd (html) and issue-14882-revealjs.qmd. The revealjs one also asserts that no unquoted declaration comes after Quarto's quoted one, since exposer.scss still writes the unquoted value first. Both fail on main and pass with this change. I also ran the brand tests, the revealjs tests and everything asserting on font-family (202 documents, 300 renders across formats): 296 pass, and the other 4 need Jupyter, LaTeX or R and fail the same way on main on my machine.

Checklist

I have (if applicable):

• referenced the GitHub issue this PR closes
• updated the appropriate changelog in the PR
• ensured the present test suite passes
• added new tests
• created a separate documentation PR in Quarto's website repo and linked it to this PR

AI-assisted PR

• AI tool used: Claude Code
• Codebase grounding: local clone
• Human review: I have reviewed, tested, and verified the AI-generated content before submitting.

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[cderv]

Thanks for the PR, and for the detailed issue.

I can reproduce on main, and the fix works for me. In Chromium, body and h2 compute to "Times New Roman" on main for the issue example, in both html and revealjs. With this PR, body, h2 and code compute to "Source Sans 3", "Bricolage Grotesque 96pt" and "M PLUS 1 Code". mainfont: Source Sans 3 in revealjs is also broken on main as you said, and fixed here.

Both new tests fail on main with assertion failures and pass with the change. With only the brand.ts change applied, the revealjs and mermaid variables still lose their quotes, so the Sass part is needed too.

I also checked a few other brand values: an already quoted family, a stack like Fira Code, monospace, generic families (serif, monospace), the object form with family and color, a dashboard, and a revealjs theme setting its own $mainFont. All come out as expected.

Re-declaring the variables in quarto.scss rather than patching the vendored exposer.scss is the approach I would choose too. Upstream reveal.js still interpolates these without inspect(), and on its main branch this block moved into settings.scss with renamed variables, so a local patch would not survive the next reveal.js update.

I will push a small adjustment to the changelog entry before merging (author attribution, and keeping it to the user-visible symptom), so no need to push anything on your side meanwhile.