Page content not displaying correctly

Hi

My wordpress is hosted on a window server. I installed the unicon theme and setup the header nicely. However the page is not displaying properly.

In my test page, I inserted only a text block and this is not showing up on my desktop screen. However when I pull the browser narrower to mimic a mobile screen, the text block show up at the bottom of the screen. Why is this so?

In addition, when I switch to the default twentyseventeen theme, everything looks fine.

Thanks!

Ticket