People won’t really want to trawl through a 2000+ line CSS file for you.
I think the easiest thing would be for you to use the developer toolbar (F12 in most browser) to find the element(s) that need to be targeted – most likely an iframe, maybe with a class or id. When you know what classes/ids/elements are involved, it will be easier to locate in the CSS.
You can make a Google map responsive by adding a wrapper div, which may or may not already be done by whatever automatic tool you’re using. You can investigate if this is the case by viewing the source of the web page via a right-click in the browser, or use the developer toolbar. If a wrapper div isn’t already in place, you will need to modify the HTML markup to include one. I do not know what zohosites is or how much access you have to modifying the template, but once you’ve done that (or worked out if there is already an existing div/element you can manipulate) here’s a way to make a Google map responsive manually https://www.ostraining.com/blog/coding/responsive-google-maps/