hi i've a problem with texts thant changes their size in various devices.
Assuming that i've a rectangle and a square in bottom-left of it that measures 30x30px, on my desktop pc and on my smartphone the text is correctly included inside the square.

But trying the same site on another device with dimension carachters set to 130%, text exceeds the square.


The font-size of the number inside the square is set to 23px.
I know that exists the "em" unity, but i'm unsure that it effectively resolve my problem.

theorically, larger is the browser char dimension, smaller should be the font-size