How to edit background color of the activity card while using Edwiser RemUI card layout in a Course
Please find the CSS for editing the Card background on the Activity page.
You need to add this CSS in Edwiser RemUI settings > General setting > Custom CSS section.
#page-course-view-remuiformat .wdm-section-wrapper .single-card-container .single-card {
background-color: red;
}