CSS style for border of editor

I did not find the style (or color) for the border of the editor.

I would like to change it to visually reflect that the editor has or not the focus.

Something like this should work…

.cm-editor { border: 2px solid orange }
.cm-editor.cm-focused { border: 2px solid blue }

It does not work.

I am using v5.6. I did not find a reference to cm-editor or cm-focused for styling in the code.

Oh, sorry, for 5.x you’ll want .CodeMirror and .CodeMirror-focused.

It does not work either.
I’ll try another method.