Interface too large on mobile

I created a touch control for a Unity application with OSC using a desktop browser (Chrome on Windows). This works fine; on a FullHD-Screen every element is shown without any user scaling.

But on an Android device (Pixel3a XL: 2160 x 1080 px / 402 ppi / Chrome, Fire HD 10: 1920 x 1200 px / 224 ppi / Silk or Chrome) only a third of the UI is visible on the screen and can’t even be scaled down. Switching to “Desktop view” doesn’t help.

Any idea what is going wrong?

The screen resolution is different from the viewport resolution as seen by the browser : for instance the Pixel 3a’s is 411x823 (according to this). Appending ?zoom=0.38 to the server’s url would compensate this device’s pixel ratio but would also probably make everything too small.

The best approach is to make your interface responsive, as discussed in this topic : Auto Responsive to Screen Size

@jean-emmanuel Thanks for the tip!
Using % for the strips and vw for the font-size in root does the job.