Black line at colophon

Try using Firefox with the Firebug add-on for this kind of CSS work.
https://getfirebug.com/

I’ll try, but what is the difference between using Firebug and designing it in Dreamweaver?

Made a quick fix by making the size .01em and the background color. A fix not an anwer.

Firebug allows you to identify what CSS needs amending or over-writing. It’s not an editor like Dreamweaver.

In the child style sheet, I deleted the following:

deleting won’t do – you need to overwrite the styles;

in your case by replacing the border style with border-top: none;

Thank you for explaining the difference.