Every time I change the header formatting/size etc on mobile, it changes how it appears on desktop

'Every time I change the header formatting/size etc on mobile, it changes how it appears on desktop'

As the title says, however, this has only just started happening,

I need the text to appear horizontally across the screen on desktop (attached) and to appear reformatted on mob (attached)

It was working fine up until this morning, when I would switch between mob/desktop editor the chnages I made in each would stick accordingly. Now, whatever changes I make on one are reflected in the other.

Could any newly added CSS be causing this?

Please help

Alex

I seem to have fixed it.

The solution was to just adjust the text manually on desktop, as opposed to using the auto button (highlighted in attached image.