Exactly matching screen background to background of movie stim

OS Win10
PsychoPy version 3.2.4

I am trying to match my screen background to the exact colour of the background of my movie stim, which is a steely-grey/white colour. I have tried using the standard colour options to specify screen colour but I can’t find an exact match. Does anyone know if it is possible to generate a hex code (or something similar) for a specific colour which I can then input into psychopy? Or if there is an eye-dropper tool I can use?