The problem is in your CSS, specifically these 3 attributes:
@media (max-width: 991px)
.sidebar {
top: 0;
max-width: 80%;
position: fixed;
}
Position:fixed and top:0 means your sidebar is forced to stick to the top of the page element, where on a mobile-view, you want the sidebar to stack above or below the content.
Changing this code to the following fixes the issue:
@media (max-width: 991px)
.sidebar {
top: auto;
max-width: 100%;
position: relative;
}
3
solved Sidebar broken on wordpress site