https://imagecolorpicker.com/en for those seeing white and gold. Also the screen you're looking at it on matters so much.
Edit: I did find a neat bug with DarkReader on though. It reads the white pixels as black with the magnifier on the right. Even turning off it's still pretty blue and white... Apparently it actually pulls the color judging by what your screen shows though... which is pretty neat all considering. The crosshair is on the large white empty space to the right of the large black stripe in the middle.
DarkReader off: https://i.imgur.com/0ofjl8W.png
DarkReader on: https://i.imgur.com/OpcDGCH.png