In the middle of the article, there is a brief discussion about icons and colors. I also think that well-coordinated color icons are good for readability and us

In the middle of the article, there is a brief discussion about icons and colors. I also think that well-coordinated color icons are good for readability and usability. https://github.com/black7375/Firefox-UI-Fix/wiki/%5BArticle%5D-1.-How-to-make-a-better-default-Firefox-UI#clearly--accessibility https://github.com/black7375/Firefox-UI-Fix/wiki/%5BArticle%... However, it is difficult to apply it universally to support a variety of colors. If it is similar to the background color, it is difficult to distinguish and there may be contrast issues depending on the light/dark theme. I think it's just the ease of development of a solid color icon that matches the color of the text.