Again, it doesn't support the "@media" rule.

[Yari27]

Is there an existing issue for this?

• I have searched both open/closed issues, no issue already exists.

CefSharp Version

117.2.40

Operating System

Windows 10

Architecture

x64

.Net Version

.Net 4.8

Implementation

WPF

Reproduction Steps

@media (prefers-color-scheme: dark) { body { color: #DEDEDE: background-color: #494949; } }

Expected behavior

Use dark body colors.

Actual behavior

Don't change body colors.

Regression?

Work in 115.3.110

Known Workarounds

No response

Does this problem also occur in the CEF Sample Application

Yes using WPF/OffScreen command line args

Other information

No response

[amaitland]

The previous upstream issue was chromiumembedded/cef#3449

Does this problem also occur in the CEF Sample Application

Yes using WPF/OffScreen command line args

Confirm that you've actually tested with the CEF Sample Application. You can grab M117 builds from https://cef-builds.spotifycdn.com/index.html

Make sure to use the WPF/OffScreen command line args that were listed in the issue template.

Once you've confirmed the problem reproduces you'll need to create an issue on https://github.com/chromiumembedded/cef/issues referencing the previous issue.

[Yari27]

This display light theme google page.
cefclient.exe --off-screen-rendering-enabled and cefclient.exe
Only after refreshing it changes to dark theme.

This display dark theme page.
cefclient.exe --url=https://dark-mode-baseline.glitch.me/ --off-screen-rendering-enabled

[amaitland]

You've dropped some command line arguments

 cefclient.exe --multi-threaded-message-loop --no-sandbox --off-screen-rendering-enabled --enable-gpu

The code for themes is at the CEF/Chromium layers, there's nothing in CefSharp that directly controls this behaviour.

You'll need to ask on https://www.magpcss.org/ceforum/index.php for further guidance.

[Yari27]

These arguments don't change anything :(

[amaitland]

You can Git Bisect the changes between v115.3.110...v117.2.40 to see exactly when the change in behaviour was introduced. Once you fix the exact commit you can compare the changes.

For what it's worth CEF recently added a new command line arg to force light/dark mode, you can see how that behaves chromiumembedded/cef#3534

This display light theme google page. cefclient.exe --off-screen-rendering-enabled and cefclient.exe Only after refreshing it changes to dark theme.

This display dark theme page. cefclient.exe --url=https://dark-mode-baseline.glitch.me/ --off-screen-rendering-enabled

The difference is probably the url being passed to the browser upon creation vs loaded later.

[amaitland]

Testing with https://github.com/cefsharp/CefSharp.MinimalExample

Google shows in dark mode by default on my machine.

Subsequently loading https://dark-mode-baseline.glitch.me/ also displays in dark mode.

Does the problem reproduce using the MinimalExample? You can fork the MinimalExample and use this as a base for your example.

Did you test with the MinimalExample as per the bug report template? How does it behave?

For me everything appears to be working as expected.

[Yari27]

I rolled back to version 115.3.110 and checked each one in turn. The last one working is 116.0.15, after this version it no longer works.

[amaitland]

Testing with https://github.com/cefsharp/CefSharp.MinimalExample

Did you test with the MinimalExample?