OK, this time I went to your link and tried it in Chrome, Opera, Firefox, and IE Edge. Firefox and Edge are the two browsers that are displaying the same messed up layout.
…so yes, you have a big problem!
You said you moved the complete site. So the big question is, was the site working in all browsers, including Firefox, before you moved it?
Something has a broken layout somewhere, whether it’s CSS from a plugin, custom CSS, or even HTML missing a single element like a missing quote, bracket, or many other possibilities can cause a broken layout. The hard part is knowing what and where this is happening.
I know there is something not related to the theme itself because if you view the demo site for Longevity in Firefox or even Edge, it works. So this tells me something else is causing the breakage.
Unfortunately, the only way to solve this is to first, know if the site worked in Firefox before being moved. If it did, that means something happened during the moving of it.
One of the common troubleshooting methods used to find out if a plugin is the problem, is to disable each plugin one-by-one, and each time test the site (in this case, in Firefox). Do this until all plugins are disabled and hopefully as you do this, you might discover if it is a plugin and which one.
I would also recommend checking your custom CSS file too because you have this in it and it should not be there because it’s javascript:
<style id="custom-css-css">
window.addEventListener (load,function (){height:window.innerHeight}
.col-main{margin-left:var(--Versatz) !important;
width:calc(630px - var(--Versatz)) !important;
width:100% !important;
max-width:800px !important
}
</style>
As a side note to why it works in Chrome and not in Firefox, it’s because some browsers are more forgiving with broken code structures, while others not so much. In the past, it was Firefox that always seemed to make sites work when other browsers did not…now it’s almost reverse of that.
