Custom CSS is not overwriting in widget through code editor

Followed the directions posted here

However even trying to overwrite the CSS inline inside the Code Editor is not reflecting. Have tried multiple methods as noted throughout the community and feel stuck.

#okta-sign-in.auth-container .okta-sign-in-header {
  border-bottom-color: orange;

Did you try with !important?
I am not sure what exactly happening from the above code snippet but you can try
border-bottom-color: orange !important;