How to enable horizontal/side scrolling for two separate web pages?

I have two webpages, created using React with absolutely positioned elements.
I need to combine them and form a horizontally stretched website.

How can I go about doing this? The tricky thing is the elements from both webpages are positioned with respect to one webpage and one width (100%), so how can I go about smoothly transitioning from one to the another?

Do I just set each page's 'body' to 50% width and have one wrapper of 100% width and overflow-x: scroll?