Background color for a specific active tab accordion element

Hi,

I’m using the accordion element and the last tab has to be a different bg color. For that I used your suggestion:

.av_toggle_section:nth-child(9) .toggler  {
  background: #5b9bd4!important;
color: #003247!important;	
}

That works fine. Could you advice what rule I should use in order to get the background (#caeaef) in active state like the first 8 tabs?

Thanks in advance!

Best regards,

Steven