[macOS][26.820.60940] Global UI text became noticeably thinner and blurry after update

Additional diagnostic evidence

I performed a direct before/after comparison of the packaged frontend assets in the two macOS desktop builds.

• 26.818.61809 (build 7019) uses this browser-scoped font stack:

``css
--font-sans-default: "OpenAI Sans", "OpenAI Sans Variable Scripts",
"-apple-system-body", "ui-sans-serif", "-apple-system",
"system-ui", "Segoe UI", ...
``

• 26.820.60940 (build 7119) changes the same browser-scoped variable to an -apple-system-body-first stack:

``css
--font-sans-default: -apple-system-body, ui-sans-serif,
-apple-system, system-ui, "Segoe UI", ...
``

The generic font default is largely unchanged; the notable difference is the browser-window-specific override. This is a packaged frontend asset change, not merely a local Appearance setting.

Neither app bundle contains an OpenAI Sans font file, so the final appearance may depend on font availability and macOS fallback resolution. However, rolling back to 26.818.61809 restores the previous font stack and the previous visual behavior.

This strongly suggests that the typography regression was introduced by the font-stack change in 26.820.60940.

Could you please confirm whether this change was intentional? If not, please restore the previous readable weight and contrast, or provide a deterministic macOS fallback and a supported font-weight control.

Additional A/B evidence: Font Smoothing toggle no longer changes text rendering

I can reproduce this regression on the current macOS Codex desktop build after the 26.820.60940 update.

The user-visible symptom is that text now appears noticeably thinner/lighter than before. Previously, setting Font Smoothing = Off produced visibly heavier/darker text; after this update, turning the setting Off no longer restores that rendering.

Controlled comparison

I captured the same Codex thread twice with no content/layout change:

1. Font Smoothing: Off
2. Font Smoothing: On

Both screenshots are 2048×1205. A pixel comparison shows:

• In a large main-content region containing the conversation prose and code block, there are 0 differing pixels between the Off and On captures.
• Across the full screenshots, only 452 pixels differ, concentrated in small/dynamic UI regions; the main rendered text is unchanged.

So this is not merely a subtle visual difference: the Font Smoothing toggle appears to have no effect on the actual conversation text rasterization in this build.

Expected behavior

Changing Font Smoothing should alter the text rendering as it did before the update, with Off restoring the heavier/darker appearance, or the setting should be removed/disabled if it is no longer supported by the renderer.

Actual behavior

Both Off and On render the same thin/light text. This makes the new typography regression impossible to work around using the existing Appearance setting.

This seems consistent with the font-stack change already identified in this issue (OpenAI Sans-first in 26.818.61809 → -apple-system-body-first in 26.820.60940). It may also indicate that the new stack/rendering path bypasses or neutralizes the existing Font Smoothing preference.

I have the paired Off/On screenshots and can provide them if needed.

same +1.

macOS 27 Beta 7 (26A5421a)

same... this is terrible... macOS 26, build 7119 / Chromium 151, Apple Silicon, previous build 6962 rendered fine

same macOS 26.3
26.820.71523

Additional evidence: global font weight changed from 445 to 400

I compared the packaged CSS from the same two macOS desktop builds and found a second typography change in addition to the font-stack change already documented above.

In 26.818.61809 (build 7019), Electron windows explicitly set:

[data-codex-window-type="electron"] {
  --vscode-font-weight: 445;
}

body {
  font-weight: var(--vscode-font-weight);
}

In 26.820.60940 (build 7119), the Electron-specific 445 override has been removed. The remaining variables resolve the normal weight to 400:

:root {
  --font-weight-normal: 400;
}

body {
  font-weight: var(--vscode-font-weight);
}

The effective global UI weight therefore changed from approximately 445 to 400.

This appears to be independent of the OpenAI Sans → -apple-system-body font-stack change. Both changes may affect the final rendering, but the explicit weight reduction directly explains why text across the sidebar, conversation, composer, and settings became noticeably thinner.

I originally reported this separately in #41047. Since the visible regression is the same, I will consolidate the evidence here and close #41047 as a duplicate.

I’m seeing the same issue on macOS after recent Codex Desktop updates, and I want to emphasize that this is an accessibility issue, not just an aesthetic preference.

For users with low vision or binocular vision issues, thinner/lighter text rendering can materially affect usability. I rely on larger UI and code font sizes, and the current rendering makes Codex significantly harder to scan during sustained work. After a couple of hours, the eye fatigue becomes noticeable.

I’ve tried several mitigations:

• increasing UI and code font sizes;
• switching the UI font to Atkinson Hyperlegible / Atkinson Hyperlegible Next;
• using Atkinson Hyperlegible Mono for code;
• selecting Medium-weight faces instead of Regular;
• slightly reducing light-theme glare with a light gray background;
• toggling the available font smoothing setting.

These help somewhat, but they do not fix the underlying issue. The problem appears to be the Electron/Chromium renderer’s effective font stack, font weight, antialiasing, or stroke rendering behavior, not simply font choice or text size.

For comparison, the same fonts look clearer and more distinct in Font Book and Emacs. iTerm2 also exposes a text rendering option, “Thin Strokes: Never,” which makes regular-weight terminal text noticeably clearer and higher contrast for my vision. Codex does not appear to provide an equivalent control, and the existing font smoothing option does not seem sufficient to recover the previous readability.

Expected behavior: Codex should preserve accessible text rendering across updates, or provide a supported accessibility option for heavier/darker text rendering. Possible fixes could include restoring the previous effective desktop text weight, making the Font Smoothing setting affect the actual renderer again, or adding a text weight / stroke darkening option similar in spirit to iTerm2’s “Thin Strokes: Never.”

Environment:

• ChatGPT / Codex Desktop: 26.820.80927 (build 7271)
• Bundle ID: com.openai.codex
• Bundled Codex CLI: 0.150.0-alpha.8
• Chromium base: 151.0.7922.170
• macOS: 26.6.2 (25G83)
• Architecture: Apple Silicon / arm64
• Runtime: owl