Prefs:

• Set browser.newtabpage.activity-stream.widgets.system.enabled to true
• Set browser.newtabpage.activity-stream.widgets.lists.enabled to true
• Set browser.newtabpage.activity-stream.widgets.system.lists.enabled to true
• In about:addons, enable Dark theme

STR:

1. Add 3+ tasks to the Lists widget until it becomes scrollable
2. Use the tab key within the Lists widget until the <fieldset> element is reached (or check focus-visible styles using dev tools)
3. Continue tabbing until the "Completed" <summary> element is reached
4. Observe the focus outline colors

Expected:
The focus outlines should use the light blue color for dark theme, consistent with other buttons in the Lists widget.

Issue:
The focus outline colors are incorrect.

Suggested fix:
Use the --focus-outline token from the design system. See Bug 1986927 for a similar fix.

Backed out for causing stylelint failures.

Backout link: https://hg-edge.mozilla.org/integration/autoland/rev/b572116c70f6fcde2c89693d9e946e5cd4ddb4b3

Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&resultStatus=testfailed%2Cbusted%2Cexception%2Cretry%2Cusercancel&revision=616a6c1a0d71175c9955bc67102307d098733a98&selectedTaskRun=Zl6mj-QUSXePvBj4CFkgww.0

Failure log: https://treeherder.mozilla.org/logviewer?job_id=538087724&repo=autoland&task=Zl6mj-QUSXePvBj4CFkgww.0&lineNumber=388

Also this bc failures.
Failure log.

(In reply to Atila Butkovits from comment #5)

Backed out for causing stylelint failures.

Backout link: https://hg-edge.mozilla.org/integration/autoland/rev/b572116c70f6fcde2c89693d9e946e5cd4ddb4b3

Push with failures: https://treeherder.mozilla.org/jobs?repo=autoland&resultStatus=testfailed%2Cbusted%2Cexception%2Cretry%2Cusercancel&revision=616a6c1a0d71175c9955bc67102307d098733a98&selectedTaskRun=Zl6mj-QUSXePvBj4CFkgww.0

Failure log: https://treeherder.mozilla.org/logviewer?job_id=538087724&repo=autoland&task=Zl6mj-QUSXePvBj4CFkgww.0&lineNumber=388

Hello, I've gone ahead and taken a look and addressed the issues. Thank you.

https://hg.mozilla.org/mozilla-central/rev/a0b2d4dc5081