How to hide editor, when not visible?

[Offerel]

Hi there, i want to set the editor to css visibility: hidden; when im in preview mode and visibility: visible; when in edit mode. The reason for this is: I want to use the Browser search function (ctrl + F). If i search for a keyword, it will be found twice, also when the editor is not visible or in use. If i understand it right, if a element is with visibility: hidden; it will not be searched by the browser.