fix: update monospace font-face for fenced code block

[bmuenzenmeyer]

Description

Adds a font-stack for pre / code blocks.

I heavily used Claude Code Opus to measure glphs and understand the problem, the fix is quite easy and surgical, suggested by me.

Validation

Watch the preview

https://api-docs-tooling-git-windows-table-openjs.vercel.app/url.html

Related Issues

Possible fix for #909

Check List

• I have read the Contributing Guidelines and made commit messages that follow the guideline.
• I have run node --run test and all tests passed.
• I have check code formatting with node --run format & node --run lint.
• I've covered new added functionality with unit tests if necessary.

[vercel]

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Project	Deployment	Actions	Updated (UTC)
api-docs-tooling	Ready	Preview	Jul 17, 2026 2:18am

[bmuenzenmeyer]

this is all i had time to do right now - will check CI in a bit

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 86.17%. Comparing base (4534824) to head (a2f9108).

Additional details and impacted files

@@ Coverage Diff @@## main #910 +/- ##
=======================================
Coverage 86.17% 86.17% =======================================
Files 188 188 Lines 17146 17146 Branches 1540 1539 -1 =======================================
Hits 14776 14776 Misses 2363 2363 Partials 7 7 

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[github-actions]

api-links Generator

Performance

Metric	Base	Head	Diff
Elapsed time	1.28 s	1.37 s	+90.00 ms (+7.03%)
User CPU time	2.75 s	2.87 s	+120.00 ms (+4.36%)
System CPU time	340.00 ms	330.00 ms	-10.00 ms (-2.94%)
Peak resident memory	348.51 MB	345.77 MB	-2.75 MB (-0.79%)

legacy-html Generator

Performance

Metric	Base	Head	Diff
Elapsed time	12.46 s	18.20 s	+5.74 s (+46.07%)
User CPU time	39.93 s	60.94 s	+21.01 s (+52.62%)
System CPU time	1.60 s	2.56 s	+960.00 ms (+60.00%)
Peak resident memory	2.33 GB	2.22 GB	-112.64 MB (-4.73%)

legacy-json Generator

Performance

Metric	Base	Head	Diff
Elapsed time	10.23 s	8.73 s	-1.50 s (-14.66%)
User CPU time	27.83 s	27.00 s	-830.00 ms (-2.98%)
System CPU time	2.06 s	1.91 s	-150.00 ms (-7.28%)
Peak resident memory	1.69 GB	1.67 GB	-26.36 MB (-1.52%)

llms-txt Generator

Performance

Metric	Base	Head	Diff
Elapsed time	7.74 s	5.25 s	-2.49 s (-32.17%)
User CPU time	23.79 s	15.53 s	-8.26 s (-34.72%)
System CPU time	1.32 s	1.21 s	-110.00 ms (-8.33%)
Peak resident memory	1.57 GB	1.85 GB	+290.93 MB (+18.10%)

orama-db Generator

Output size

| File | Base | Head | Diff |

|-|-|-|-|

| orama-db.json | 8.90 MB | 8.90 MB | -1.00 B (-0.00%) |

Performance

Metric	Base	Head	Diff
Elapsed time	8.38 s	8.76 s	+380.00 ms (+4.53%)
User CPU time	23.44 s	26.47 s	+3.03 s (+12.93%)
System CPU time	1.44 s	1.97 s	+530.00 ms (+36.81%)
Peak resident memory	1.59 GB	1.76 GB	+167.56 MB (+10.28%)

web Generator

Output size

| File | Base | Head | Diff |

|-|-|-|-|

| all.html | 21.27 MB | 21.27 MB | -158.00 B (-0.00%) |
| styles.css | 141.88 KB | 141.99 KB | +106.00 B (+0.07%) |

Performance

Metric	Base	Head	Diff
Elapsed time	77.88 s	77.17 s	-710.00 ms (-0.91%)
User CPU time	161.49 s	170.11 s	+8.62 s (+5.34%)
System CPU time	4.90 s	4.62 s	-280.00 ms (-5.71%)
Peak resident memory	5.59 GB	5.75 GB	+158.13 MB (+2.76%)

[cursor]

PR Summary

Low Risk
Presentation-only CSS scoped to pre; no logic, auth, or data changes.

Overview
Fixes misaligned ASCII-art diagrams in fenced code blocks (e.g. the URL table) on Windows by not rendering those blocks entirely in IBM Plex Mono.

Inside main pre, the PR redefines--font-ibm-plex-mono to a system monospace stack (SFMono-Regular, Menlo, Consolas, etc.)—the same stack the legacy-html generator uses. Box-drawing characters (U+2500–U+257F) are missing from Plex/Google Fonts and were falling back per-glyph to OS monospace with different advance widths than Plex letters, which sheared diagrams. Scoped to pre only so inline code and other UI (e.g. search shortcut keys) still use IBM Plex Mono via the root variable.

^{Reviewed by Cursor Bugbot for commit a2f9108. Bugbot is set up for automated code reviews on this repo. Configure here.}

[avivkeller]

Is this a doc-kit specific issue, or should this fix be upstreamed to ui-components

[MikeMcC399]

https://api-docs-tooling-git-windows-table-openjs.vercel.app/url.html looks good on my WIndows 25H2 system as well.

[bmuenzenmeyer]

Is this a doc-kit specific issue, or should this fix be upstreamed to ui-components

I can check today by recreating the table in some website about markdown.

[bmuenzenmeyer]

Is this a doc-kit specific issue, or should this fix be upstreamed to ui-components

I can check today by recreating the table in some website about markdown.

Locally within the docs site, it might be even worse

[bmuenzenmeyer]

nodejs/nodejs.org#9015 now fixes this upstream