How to split posts on the front page in Blogger?

Question

Blogs

How do I separate posts with a bar, border, or other way in Blogger on the front page?
I used the given code:

.post-body {  line-height: 1.4;  position: relative;  border-bottom:3px double #000; }

But the result turned out like this:
A dash appeared over the date of publication, information about comments, etc.
How to lower it even lower? Or is there another way to separate posts?
Now the posts going one after another look like this:

spoiler

Answer 1

I found a solution, I used the following code:

.post.hentry {
padding: 5px;
border: 1px solid  #ff0000;
}

Taken from here (there are several other examples there)

Answer 2

can you link to the project? And then we will poke a finger in the sky here.
as an option to give sections with a margin-bottom post
and in general. what's the problem with indenting this stripe...