Use pointer based internal drag and drop

server/public/styles.css

@@ -229,16 +229,30 @@
 
 .u-nav .file-row:hover,
 .u-nav .file-row.selected,
-.u-nav .file-row.dragging {
+.u-nav .file-row.dragging,
+.u-nav .file-row.drop-target {
   background: var(--surface-2);
 }
 
 .u-nav .file-row:hover td,
 .u-nav .file-row.selected td,
-.u-nav .file-row.dragging td {
+.u-nav .file-row.dragging td,
+.u-nav .file-row.drop-target td {
   background: var(--surface-2) !important;
 }
 
+.u-nav .file-row {
+  user-select: none;
+}
+
+.u-nav .file-row.dragging {
+  opacity: 0.55;
+}
+
+.u-nav-dragging {
+  cursor: grabbing;
+}
+
 .u-nav .name-cell {
   align-items: center;
   display: flex;