A neat way to add CSS to a document is to find a way to detect a platform then inject a CSS class. It combines a small JS detection with a special header feature in these browsers called user-agent client hints.
What it does: target a specific element (DIV, etc…) and add a class to it. In this case either class .win10 or .win11 based on what is detected by the chrome based browser.
See it in action: