If, for reasons, you want to take the style of a responsive website and use it in a local file, you could: load the site, download the page (using the "Web Page, Complete") setting. And then take hours trying to remove the DOM alterations that the browser performed on your behalf.
Or, you can use a simpler method.
- Load the page
- Save as "Web Page, Complete" in a new folder, and call the file "index.html"
- In the saved folder, change the "index_files" folder to "src"
- In the index.html file, replace all "index_files" references to "src"
You should now have a somewhat exact copy of the site stored locally.
Be sure to remove any analytics or remote sources, depending on what the page had.