Unusually narrow content

I’m unsure whether what I describe below is due to some recent change in the forum design or down to my iPhone 13 Pro, perhaps the recent iOS update to 18.4.1.
In summary text I would normally expect to occupy most of the screen width in portrait (vertical) mode is crammed into at most a quarter, at the left.

I’m unfortunately unable to add a screenshot - maybe a related issue? - but will try again when I get back to Chrome on my PC in the morning.

EDIT
Just tried the iPhone Chrome browser instead of my usual Safari and that is behaving normally. So clearly looks like a Safari issue. Anyone able to confirm please?

I have noticed some changes in screen width as well but I just ignore them and just adjust the zoom to size it where I like it. I am using Linux Mint and FireFox.

Thanks for the feedback. Pleased to confirm that Safari was the culprit. Much playing with settings, cache, etc followed by a couple of iPhone reboots and all now seems OK.

For anyone curious, here's the screenshot I was unable to attach.

That is what I saw, I simple zoomed and the problem went away.

Latest Safari sounds to be the culprit. @J-M-L posted about Wokwiki and really big font on PCB's when using Safari in Mac.