(@media prefers-)color-scheme - doesn't work by default on Samsung Internet

What type of issue is this?

Browser bug (a bug with a feature that may impact site compatibility)

What information was incorrect, unhelpful, or incomplete?

By default in Samsung Internet neither color-scheme nor @media prefers-color-scheme do anything. Instead Samsung takes the default styling and uses their own version of "Dark theme", inverting the colors automatically. To get "intended" CSS behaviour you need to change settings in experimental options Labs -> Use website dark theme - which seems a bit out of reach for regular users.

What browsers does this problem apply to, if applicable?

Chromium (Chrome, Edge 79+, Opera, Samsung Internet)

What did you expect to see?

Samsung applying automated dark mode only as a fallback - if there is no dark theme listed in color-scheme property.

Did you test this? If so, how?

Reproduction example in CodePen

Results:
Default Samsung Internet settings, when using System Dark theme
Chrome, when using Chrome's Dark theme

Tested on Android phone with Samsung Internet, using all combinations of color-scheme (both as css and meta) and @media prefers-color-scheme value I could think of.

Can you link to any release notes, bugs, pull requests, or MDN pages related to this?

Samsung announcement:
https://developer.samsung.com/internet/blog/en-us/2020/12/15/dark-mode-in-samsung-internet

Keeping in line with the WebView implementation, Samsung Internet now provides the ‘Force Dark Behavior’ options as an experimental feature under internet://flags.

Despite being from 2020, it still seems to apply.

Do you have anything more you want to share?

Not official, but this blog has a well written description on Samsung Internet's behaviour:
https://www.ctrl.blog/entry/samsung-internet-night-mode.html

MDN URL

No response

MDN metadata

No response

Start by locating the browser-compatibility-data entry for color-scheme and review the linked Samsung announcement and CodePen reproduction. Confirm how default Samsung Internet handles color-scheme and prefers-color-scheme, then update the compatibility data so the documented behavior matches the evidence.