Luminosity ratio of ‘This is the subtitle’ text is less than 4.5:1.

Is it an issue related to Adaptive Cards?

Yes, this is related to Adaptive Card. However, it does not repro on Adaptive Cards Designer.

What is the PWD impact?

When the “This is the subtitle” text has a luminosity contrast ratio less than 4.5:1, users with low vision or those in bright or high‑contrast environments may struggle to read it. This reduces readability, causes eye strain, and excludes users who depend on sufficient text contrast.

What browsers and screen readers do this issue affect?

Windows: Edge with Windows Narrator

Are there any code-based customization done to Web Chat?

No, I am using Web Chat without any customizations except "styleOptions".

What version of Web Chat are you using?

Latest production

Which area does this issue affect?

Others or unrelated

What is the public URL for the website?

No response

How to reproduce the issue?

Repro Steps: ​

1. Open URL: Web Chat in edge browser.
2. Ask query 'Carousel'.
3. Check the CCA of ‘This is the subtitle’ text.
4. Observe the issue that Luminosity ratio of ‘This is the subtitle’ text is less than 4.5:1.

What do you expect?

Luminosity ratio of ‘This is the subtitle’ text should be equal or greater than 4.5:1.

What actually happened?

Luminosity ratio of ‘This is the subtitle’ text is less than 4.5:1.

Do you have any screenshots or recordings to repro the issue?

Did you find any DOM elements that might have caused the issue?

No response

MAS reference

No response

WCAG reference

https://www.w3.org/WAI/WCAG21/Understanding/contrast-minimum

WAI-ARIA reference

No response

Adaptive Card JSON

Additional context

No response

Reproduce the issue in Web Chat using Edge, the Carousel query, and the existing styleOptions, then inspect the rendered subtitle text and its computed colors. Compare the result with the WCAG contrast-minimum reference; done means the subtitle’s luminosity ratio is at least 4.5:1.