Hi again,
Apologies, there was a syntax error in the code, you should try this one instead:
$el.x-acc .x-acc-header[class*="active"] {
color: red !important;
background-color: white !important;
}
$el.x-acc .x-acc-header[class*="active"] .x-acc-header-indicator {
color: red !important;
}
However for Inactive and Hover states you can set the color and background color from the Accordion element settings in Cornerstone. For example to set the item transparent, go to Accordion > Items tab (see screenshot)

Under Item Setup, set the Background to transparent (see screenshot)

Now head over to Accordion > Header tab:

Under Header Setup, set the background Base color to transparent and Interactive color as per your need (see screenshot)

Hope this helps!