Hi there,
Thanks for writing in! You can add this under Custom > CSS in the Customizer or in your child theme’s style.css file.
.x-accordion-heading .x-accordion-toggle.collapsed {
background-color: #252525;
color: #ffffff;
}
.x-accordion-heading .x-accordion-toggle {
background-color: #555555;
color: #ffffff;
}
.x-accordion-heading .x-accordion-toggle:hover {
color:#aaa;
}
Just Change the color values as needed. Hope this helps – thanks!