Resizability?

So, I have finished laying out my webpage, for the most part, but I’ve been using a giant mac monitor to do so. As soon as I re-size the window, everything shifts around and loses it’s layout and styling.

How do I keep everything in the same place when the window is resized?

I can post my code if you like, but it would be quite long. what do you need to see to help me?

The website is https://www.thinkinkutah.com/whyrefill.

Thnks!