[SOLVED] how to remove title AND its line space from a Page

There is a thread (closed) that says to remove title from all pages/posts:

body.page-id-2818 div.post-headline h1, div.post-headline h2 {display: none;}

But i want to remove from only one specific page per this photo. The above does not tell me where to insert the code, so that too would be greatly appreciated. Thanks in advance.