Sidebar keeps going to the bottom after styling border

Without a link to your site, no way to help with something like this — though it’s likely a width issue – if you add width to the sidebar and it no longer fits in the space where it belongs, it will fall below the element next to it.

Sorry about that.

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I used Firefox inspection to text it out but to no avail.
Here is the original css code.
#sidebar {
float: left;
width: 220px;
color: rgb(51, 51, 51);
line-height: 36px;
}

I only made tweaks to the background color and the psuedo class.

Yep, that seems to be the problem — this is the CSS code for the sidebar:

#sidebar {
    color: #333333;
    float: left;
    line-height: 36px;
    width: 220px;
}

So if you add width via a border, you’ll need to reduce the width. It looks like you are using custom CSS? If so, you can just add this:

#sidebar {
    width: XXXpx;
    border: xxxxx  ;
}

Obviously, you’ll need to put in the specifics.

It worked! Thank you WPyogi!
One more question. I’m using Jetpack’s css editor. Do you know where all the css revisions that I make go?