feat(bases): drop cards onto empty kanban columns / below last card

apps/client/src/features/base/components/views/kanban/kanban-column.tsx

@@ -4,6 +4,7 @@ import { KanbanCard } from "./kanban-card";
 import { KanbanColumnHeader } from "./kanban-column-header";
 import { KanbanAddCardButton } from "./kanban-add-card-button";
 import type { CardDropPayload } from "@/features/base/hooks/use-kanban-card-drag";
+import { useKanbanColumnDrop } from "@/features/base/hooks/use-kanban-column-drop";
 import classes from "@/features/base/styles/kanban.module.css";
 
 type KanbanColumnProps = {
@@ -21,6 +22,11 @@ export function KanbanColumn({
   onAddCard,
   onCardDrop,
 }: KanbanColumnProps) {
+  const { ref: bodyRef, isOver } = useKanbanColumnDrop({
+    columnKey: column.key,
+    onDrop: onCardDrop,
+  });
+
   return (
     <div className={classes.column} data-column-key={column.key}>
       <KanbanColumnHeader
@@ -28,7 +34,12 @@ export function KanbanColumn({
         color={column.color}
         count={column.rows.length}
       />
-      <div className={classes.columnBody} data-column-body={column.key}>
+      <div
+        ref={bodyRef}
+        className={classes.columnBody}
+        data-column-body={column.key}
+        data-over={isOver || undefined}
+      >
         {column.rows.map((row) => (
           <KanbanCard
             key={row.id}

apps/client/src/features/base/hooks/use-kanban-column-drop.ts

@@ -0,0 +1,48 @@
+import { useEffect, useRef, useState } from "react";
+import { dropTargetForElements } from "@atlaskit/pragmatic-drag-and-drop/element/adapter";
+import type { CardDropPayload } from "./use-kanban-card-drag";
+
+export const COLUMN_BODY_TARGET_ID = "__column-body__";
+
+export function useKanbanColumnDrop({
+  columnKey,
+  onDrop,
+}: {
+  columnKey: string;
+  onDrop: (payload: CardDropPayload) => void;
+}) {
+  const ref = useRef<HTMLDivElement>(null);
+  const [isOver, setIsOver] = useState(false);
+  // Keep onDrop fresh without re-registering the effect each render.
+  const onDropRef = useRef(onDrop);
+  onDropRef.current = onDrop;
+
+  useEffect(() => {
+    const el = ref.current;
+    if (!el) return;
+    return dropTargetForElements({
+      element: el,
+      canDrop: ({ source }) => source.data.type === "base-kanban-card",
+      getIsSticky: () => true,
+      onDragEnter: () => setIsOver(true),
+      onDragLeave: () => setIsOver(false),
+      onDrop: ({ source }) => {
+        setIsOver(false);
+        if (source.data.type !== "base-kanban-card") return;
+        // If a card-level target inside this column already handled the
+        // drop, Pragmatic-dnd only invokes the innermost matching target,
+        // so this column-body handler won't fire. When it does fire, the
+        // user missed every card — append to the column.
+        onDropRef.current({
+          draggedCardId: source.data.cardId as string,
+          targetCardId: COLUMN_BODY_TARGET_ID,
+          edge: "bottom",
+          sourceColumnKey: source.data.columnKey as string,
+          targetColumnKey: columnKey,
+        });
+      },
+    });
+  }, [columnKey]);
+
+  return { ref, isOver };
+}

apps/client/src/features/base/styles/kanban.module.css

@@ -52,6 +52,10 @@
   min-height: 80px;
 }
 
+.columnBody[data-over="true"] {
+  background: var(--mantine-color-blue-0);
+}
+
 .card {
   padding: 10px 12px;
   background: var(--mantine-color-body);