A toolbar can look correct in light and dark mode and still become difficult to use with a Windows contrast theme.

The missing check is forced colors : a browser mode that applies a restricted, user-selected palette to the page.

For SVG icons, this raises a different question from ordinary theme support:

When the surrounding interface changes to system colors, does the icon remain recognizable—and does the control still look like a control?

This article explains the documented behavior and a practical way to check it. It does not present results from a completed Windows browser comparison.

Start with the rendered control

A contrast calculation evaluates a foreground against a background.…