There are multiple ways to go about implementing "zoom" in browsers. You may be able to change this in a setting somewhere. Nowadays the default way to do zoom

There are multiple ways to go about implementing "zoom" in browsers. You may be able to change this in a setting somewhere. Nowadays the default way to do zooming is to pretend the entire page is being rendered at a different resolution than the real screen. You can view this in action by typing "window.screen" in your browser console, zooming, then checking that variable again (in Chrome check window.visualViewport). Pretending here means the browser (if it's Firefox) lies to JavaScript and when computing the layout, but then scales pixel values back to real screen values before rendering. That's why stuff generally won't look pixelated[1]. [1]: A notable exception is canvas elements. Since a script may decide to use a lower resolution for them.