Drawing a line in the right sidebar

I’m trying to draw a simple line in between text items in my sidebar.

I found on another website the following code which I added to the stylesheet of the theme I am using.

hr {
height: 1px;
border: 0;
color: #000000;
background-color: #000000;
width: 80%;
}

I added the <hr> command to my sidebar template. Is this the right way to draw a simple 1px line?

It doesnt seem to work. Using just <hr> doesn’t work as well. Can anyone advise? Thanks.