Add this code to your Custom CSS area.
/**
* Outline Accordion Style
* From Will-Myers.com
**/
[data-wm-plugin="accordions"] {
--wm-accordion-item-space-between: 14px;
--wm-accordion-item-border-radius: 8px;
--wm-accordion-item-border-width: 1px;
--wm-accordion-title-padding-left: 14px;
--wm-accordion-title-padding-right: 14px;
}