[Windows] System default UI font becomes semi-transparent when Translucent sidebar is enabled

What version of the Codex App are you using (From “About Codex” dialog)?

26.810.7004 (Microsoft Store package OpenAI.Codex_26.810.7004.0_x64)

What subscription do you have?

Not relevant to this rendering issue; exact tier not verified.

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64 (Windows 11, Simplified Chinese display language)

What issue are you seeing?

When the UI font is set to System default and Translucent sidebar is enabled, the text opacity appears to be reduced across the entire Codex/ChatGPT desktop UI—not only inside the sidebar.

Text in the conversation area, menu bar, and application menus looks washed out or partially transparent. The effect is especially easy to see in the View menu in the attached comparison screenshots. Breaking the trigger combination (by disabling the translucent sidebar or choosing a non-system UI font) restores normal text contrast.

This is reproducible and appears to be an interaction between the system-font rendering path and the translucent window/compositing style.

What steps can reproduce the bug?

1. Open Settings → General → Appearance.
2. Set the UI font to System default.
3. Enable Translucent sidebar.
4. Return to the main window and inspect text in the sidebar, conversation area, menu bar, and the View or Help menu.
5. Disable Translucent sidebar, or select a non-system UI font, and compare the text contrast.

What is the expected behavior?

The translucent effect should apply only to the intended background/sidebar surface. UI glyphs throughout the window should keep their normal, fully opaque text color regardless of the selected UI font.

Additional information

I searched the existing issues and did not find a report for this exact trigger combination. Issues such as #25249, #25374, and #25806 concern transparent window/sidebar backgrounds; this report is specifically about the global text opacity changing only when System default and Translucent sidebar are used together.

The screenshots are tightly cropped to avoid unrelated content. The UI language is Simplified Chinese, but the contrast difference is visible in the same menu items:

Normal text contrast after breaking the trigger combination:

!Normal text rendering

Bug reproduced with System default + Translucent sidebar (capture 1):

!Washed-out text with System default and Translucent sidebar

Bug reproduced again (capture 2):

!Second reproduction of washed-out UI text