Page Not Responding As It Use To In Preview?

Hello there!!
I have been trying all day to work out what I’m doing wrong so hopefully someone can help me - it seems fairly simple but my brains not working!!
I’ve set up my landing page at 1200 and in preview it works fine, it sits in the middle of the screen, with space altering either side depending on screen size, working as it should. Now I’m onto the next page but it’s not playing the same game and it’s adjusting everything to the left in preview, on centered? This off centers everything I’m doing with the top and bottom bar? I have shown a simple example in the pics - what am I doing wrong here? Have I been looking at this too long??

Any help would be super appreciated.


Thanks
David

What does “space altering either side” mean?

Also, can send screenshots of what it’s looking like on your page that is working?

Where do you think you’ve centered it? Click that blue rectangle and go to layout and center it.

Thanks for your help.

I think what it’s about is the 1200 space not centring in the screen in preview and justify everything left? This does’t seem right as it should respond to peoples screen resolutions and sit centre screen and adjust accordingly? Here it’s sitting 1200 from the left, this is not the right UX I don’t think?

Here’s a ship of my landing page where it’s all centred on the screen so I know it works and how it should? I’m confused?