I am trying to have all of the elements scale up as the screen size grows, and then once they reach a certain size, stay fixed and only have the margins get bigger around them.
All of my elements are in containers, many of them are also in stacks. I’ve been able to get everything to either grow proportionally or stay fixed, but I can’t figure out how to do both.
Please help! Thank you!
It all depends on what elements and how they are set up, but in short you can enable advanced sizing and set min/max sizings on everything in px.
Hey @Sophie_Campbell! There is a current feature request for this: Studio Editor Request: Setting the Max Width Value of a Site. Be sure to submit your vote for it! I have heard there is something in the works coming very soon 
@Sophie_Campbell Hey! 
I just wanted to make sure that you saw max-width has begun rolling out! It was a major request that many people had asked about, so hopefully you find it useful! See the announcement here