Now mainstream operating systems support dark mode so that users will not be too glaring at night, and many browsers and websites are actively adapting to dark mode. Although the dark mode looks good, the browser’s scroll bar sometimes breaks the style, because the browser’s scroll bar is usually displayed in gray and white. Firefox has now added scrollbar adaptation to the nightly build, which can be displayed in a specific color according to the website instructions.
The biggest goal of the Firefox browser to add this feature is to improve the night mode. The scroll bar displays the specified color when the site specifies the color of the scroll bar in the style sheet, and the scroll bar automatically adjusts to a darker color when the site is in dark mode. The web developer can decide how to handle the style sheet according to the actual style of the website, and then the Firefox browser will process the style sheet according to the style sheet. This improvement is good news for sites that use dark mode, at least to make the scrollbars on the side not as sharp and uncomfortable as before.
Source, Image: Reddit