Code diff view is not accessible for people with red-green color blindness

Open 💬 11 comments Opened Feb 3, 2026 by matthiaswitt

💡 Likely answer: A maintainer (guidedways, contributor) responded on this thread — see the highlighted reply below.

What version of Codex is running?

Codex App and IDE extensions

What subscription do you have?

Plus

Which model were you using?

_No response_

What platform is your computer?

macOS

What terminal emulator and version are you using (if applicable)?

VSCode

What issue are you seeing?

Problem

The current color scheme in the code diff view uses red and green tones that are difficult or impossible to distinguish for people with red-green color blindness. Red-green color blindness affects approximately 8% of males and 0.5% of females – that's around 300 million people worldwide.

What steps can reproduce the bug?

Current Behavior

Added/removed lines are displayed in green and red
Color is the main visual distinction between additions and deletions
Insufficient brightness/contrast between the two colors

What is the expected behavior?

Expected Behavior

The diff view should be accessible to all users through improved contrast or customizable color schemes.

Additional information

References

Priority

Medium to High – affects accessibility and potentially millions of users

View original on GitHub ↗

11 Comments

commanderperkins · 5 months ago

andreszs · 5 months ago

Isn't the diff window theme-dependent?

As far as I know you can edit and create arbitrary themes from VSCode itself in a matter of minutes using any decent agent -- certainly this excludes Copilot Pro's _GPT-4.1_ and _GPT 5 "mini"_, which are artificially slow and completely worthless for serious coding tasks, but if you have a paid Claude.ai account, it will do it in 1 prompt for sure.

harvitronix · 5 months ago

Extra context: I have to use dark mode in the Codex IU because the light mode diff is unreadable for me. The green and red on grey all blend together. I don't see any theme options in the UI - note that this is specifically for the macOS desktop app.

matthiaswitt · 5 months ago

Isn't the diff window theme-dependent?

True, but not in the codex standalone app. Also this should be theme independent

gjakubik · 5 months ago

Adding a plus one here, the pattern I like the best is an accessibility setting for colorblindness that changes these colors (and any others like the +,- line indicators on threads) depending on which type of colorblindness you have.

danielcompton · 5 months ago

I'm colorblind and find the current colorscheme hard to read. The https://gitup.co green and red I find very readable.

guidedways contributor · 4 months ago

I think recently text / syntax coloring got added (v0.105.0-alpha.13), which is great, but the lack of a background highlight color makes it impossible to see what got added and what got removed. The little + / - are hard to see (I've got red-green color blindness but otherwise had no issue noticing the highlights from before and telling them apart), now it's near impossible to tell what changed

fcoury contributor · 4 months ago

@guidedways mea culpa on the accessibility shortcomings. Believe it or not, I am also colorblind but this particular difference doesn't affect me, and I think that's why it slipped through.

I am tweaking it now and would really like your input on this first tweak:

Is this a step in the right direction or still hard to differentiate?

guidedways contributor · 4 months ago

@fcoury thank you! This looks great to my eyes, easy to tell the diffs apart (which got lost in the recent builds). I see themes are now configurable and perhaps if the background row highlighting can be user-configured, users could tweak and create custom themes as needed.

harvitronix · 4 months ago

@fcoury I know it's challenging to address everyone's accessibility problems, but in the screenshot you posted, I can't tell those apart at all. :/