Remove Thematic borders

Look at adding a border of zero to the navigation element:

<div id="access">

https://www.w3schools.com/cssref/pr_border-style.asp

Thanks!

With my lack of webdesign knowledge you’ll have to be a tad more specific though.

Where do I put what?

CSS modifications go in your Child Theme style.css file.

So at the bottom of my stylesheet I’d put:

<div id=”access”>
{
border:0px;
}

?

Not quite.
You don’t put the HTML literally like that in CSS.

CSS applies styles to HTML elements by picking out the classes, IDs or literally the tag itself through its own method called “CSS Selectors”.

You can read up on CSS selectors here: https://developer.mozilla.org/en-US/docs/Web/Guide/CSS/Getting_started/Selectors .