sticky enabled tables: remove layout shift

dist/css/base/gin.css

@@ -1439,6 +1439,10 @@ table.position-sticky thead {
   position: static;
 }
 
+table.position-sticky.--is-processed thead tr {
+  border-color: transparent;
+}
+
 table thead {
   background: transparent;
   border-radius: var(--gin-border-m);

dist/js/tableheader.js

@@ -20,10 +20,12 @@
     },
     updateTableHeader: function(el) {
       const tableHeader = document.querySelector(".gin--sticky-table-header");
-      tableHeader && (tableHeader.style.marginBottom = `-${el.querySelector("thead").getBoundingClientRect().height + 1}px`, 
-      tableHeader.querySelectorAll("thead th").forEach(((th, index) => {
+      if (!tableHeader) return;
+      const offset = el.classList.contains("sticky-enabled") ? -7 : 1;
+      tableHeader.style.marginBottom = `-${el.querySelector("thead").getBoundingClientRect().height + offset}px`, 
+      el.classList.add("--is-processed"), tableHeader.querySelectorAll("thead th").forEach(((th, index) => {
         th.style.width = `${el.querySelectorAll("thead th")[index].getBoundingClientRect().width}px`;
-      })));
+      }));
     }
   };
 })(Drupal, once);
\ No newline at end of file

js/tableheader.js

@@ -38,7 +38,9 @@
       const tableHeader = document.querySelector('.gin--sticky-table-header');
       if (!tableHeader) { return; }
 
-      tableHeader.style.marginBottom = `-${el.querySelector('thead').getBoundingClientRect().height + 1}px`;
+      const offset = el.classList.contains('sticky-enabled') ? -7 : 1;
+      tableHeader.style.marginBottom = `-${el.querySelector('thead').getBoundingClientRect().height + offset}px`;
+      el.classList.add('--is-processed');
 
       tableHeader.querySelectorAll('thead th').forEach((th, index) => {
         th.style.width = `${el.querySelectorAll('thead th')[index].getBoundingClientRect().width}px`;

styles/base/_table.scss

@@ -73,6 +73,10 @@ table.position-sticky {
   thead {
     position: static;
   }
+
+  &.--is-processed thead tr {
+    border-color: transparent;
+  }
 }
 
 table {