Setting Maximum Width for all content on website

Hello, I am trying to set a maximum scaling size to a website I am designing and have tried some code options but none have worked. Is there a way to make sure all text and content stops scaling at a specific width? 

This is the code I am working with so far: 
#site{
     max-width: 1920px; /*Adjust here.*/
     margin-right: auto;
   margin-left: auto;}
//limit nav/logos/titles
.header-inner {
  max-width: 1920px; /*Adjust here.*/
}

siteurl:  https://hystudio.squarespace.com/
pwd:   hystudio

You mean prevent text change size when screen width change? If yes, you will need to set text-size for these text. You can let me know which text you want to apply, I can check code easier

I would like all the assets including text and images to stop scaling at a specific width so that the content is not too big on larger screens. I am okay with there being some margin on either side as a result.