Makes the browser use the user's preferred color scheme to render the viewport scrollbars if the value of "page’s supported color schemes" is 'normal' or not specified, and the computed value of the color-scheme for the root element is 'normal'. Viewport scrollbars can be considered to be outside the web content. Therefore, the user agents should honor the user's preferred color scheme when rendering viewport scrollbars if page authors have not explicitly specified support for color schemes.
Many web pages don't specify the support for light/dark color schemes using CSS "color-scheme" property or meta tags. In such a case, the used color scheme is light for scrollbars and other interactive UI elements despite the user preference set on the browser/OS level. Although the behavior is expected for elements which are part of the web content, viewport non-overlay scrollbars always stay on the side of the page and are treated by users as a part of the browser UI. The current behavior confuses users who have selected dark mode and expect viewport scrollbars to follow their choice. Edge users repeatedly reported the viewport scrollbars being light when dark mode is enabled. These are a few public feedback items: https://www.reddit.com/r/MicrosoftEdge/comments/xrf1wb/scrollbars_are_wh https://www.reddit.com/r/chrome/comments/lz0778/any_way_to_remove_or_turn_dark_ https://www.reddit.com/r/ArcBrowser/comments/18ldsj2/why_in_dark_mo Relevant Chromium and Mozilla issues: https://issues.chromium.org/issues/40155812 https://bugzilla.mozilla.org/show_bug.cgi?id=1859940 The feature doesn't impact developer APIs and still allows to control the color scheme for scrollbars and other controls. The new behavior makes the browser use the user’s preferred color-scheme to render viewport non-overlay scrollbars when page authors don’t specify the color scheme for the root element.