How to style the posts feed on the main page in Drupal?

Question

PHP

There is a feed of 5 posts on the main page, displayed in a standard way without the VIews module. It is necessary to radically change the markup of these posts. Those. the first post should be with a certain class and with a certain markup, i.e. just editing css is not enough. Which template to edit?
PS
If anyone knows, tell me the resources where you can read/look about customizing individual pages in Drupal. New to this thread

Answer 1

Well, the easiest way. Enable the Views module, enable the Front Page, output, each post will have its own css access:

views-row-1
views-row-2
views-row-3
views-row-4
и т.д.

If I'm not talking about this, but about the fact that, for example, the first node would be at the top, the other 3 are allowed there at the bottom, before sawing Panels.