The picture above is my accordion.

When it was collapsed, it looks like this:

I tried searching for the CSS in the theme (LisbonTheme), but no luck.

I know I'm doing something wrong here since I am not also familiar in CSS.

How will I be able to remove the bottom border of accordion header (Color grey) when it was collapsed?

Many thanks!!!

I don't know which kind of application you are building, Traditional or Reactive? Because when I using accordion in the traditional web app,  By default the borderline only appears when it's open, also on the top, not the bottom. 

Anyway, I believe you can change CSS to achieve this. Please watch the URL bellow, It's should help you.

Kindly regards

Hi Arci,

As Tom mentinoed, it depends which type of app are you using. For instance in reactive, You may have to modify the css of . The default CSS looks as below.

section-expandable-title {
  border-top: var(--border-size-m) solid var(--color-primary);

Remove the solid from its property of border-top.