font size

Hi;

I have used the following code for font size:

At the time of running, when the window is maximized, everything is right, but when the window size becomes small, the text breaks down:

What is the cause?

i suppose its because "em" is an exact measurement-

its the same with px-

if u set a button border to 3px in small screen-it is 3px in small screen

if u set a button border to 3px in big screen-it is 3px in big screen

but if u set a sprite to 300*300 it will show bigger in big screen.

id kwhy tho