I know this is going to sound ridiculously easy and you most likely have tried it, However sometimes simplicity evades us all at times.
If you have windows 10, then you have EDGE as the main browser.
Open the game up, or any web site.
Up in the right hand top corner of your screen are 3 horizontal dots.
Have you pressed on those? It opens the menu for using the ZOOM feature.
I play this game on a 17" HP laptop at 125% zoom, it's great for the fonts size in the forums and does very well in the arena.
When you want to close the zoom window click your mouse any where on the web page.
I'm only 6, so just saying, you still may need the 8 year old