make second row in header follow when scrolling

compendium-frontend/src/scss/layout/_components.scss

@@ -317,13 +317,20 @@ $service-check-colors: (
   word-wrap: break-word;
 }
 
-.charging-struct-table thead th {
+.charging-struct-table thead tr:first-child th {
   position: sticky;
   top: -1px; // to hide the pills scrolling by the top of the header
   background-color: white;
   z-index: 1;
 }
 
+.charging-struct-table thead tr:not(:first-child) th {
+  position: sticky;
+  top: 50px;
+  background-color: white;
+  z-index: 1;
+}
+
 @mixin line-before {
   content: '';
   position: absolute;