scaling text

Hello,

I have this very simple page with a symbol with rectangle as a background and text which will explain people what to do.

I apply the code from Sarah Hunt to scale my stage depending on the size of the browser window. It works ok. The button and the rectangle scales ok but the text

replaces itself !

When I try to use Responsive scale, the text scales ok but the page behaves on a strange way. Sometime it works sometimes it doesn't.

Thanks for any help.