fix

assets/flex-kit/flex-kit.css

@@ -714,7 +714,7 @@ script, style {
     display: flex;
     flex-direction: column;
     justify-content: stretch;
-    border-width: 1px;
+    border-width: 0;
     border-style: solid;
     border-color: #e9e9e9;
     /*border-radius: 3px;*/
@@ -724,6 +724,18 @@ script, style {
     /*padding-bottom: calc(var(--gap-inner) / 2);*/
     /*padding-top: calc(var(--gap-inner) / 2);*/
 }
+.flex-card__border {
+    position: absolute;
+    left: 0;
+    top: 0;
+    width: 100%;
+    height: 100%;
+    border-width: 1px;
+    border-style: solid;
+    border-color: transparent;
+    display: block;
+    pointer-events: none;
+}
 .flex-card__content:after,
 .flex-card__body:before,
 .flex-card__body:after {
@@ -733,7 +745,7 @@ script, style {
     flex-grow: 0;
     flex-shrink: 0;
 }
-.flex-card__content > *:empty {
+.flex-card__content > *:not(.flex-card__border):empty {
     display: none;
 }
 .flex-card__header {
@@ -764,7 +776,7 @@ script, style {
     opacity: 0;
     visibility: hidden;
 }
-.flex-card.flex-card--hover:hover .flex-card__content {
+.flex-card:hover .flex-card__content {
     height: auto;
     z-index: 100;
 }