diff --git a/frontend/components/screen/RealtimePreviewDynamic.tsx b/frontend/components/screen/RealtimePreviewDynamic.tsx
index 14314a61..6330b8d4 100644
--- a/frontend/components/screen/RealtimePreviewDynamic.tsx
+++ b/frontend/components/screen/RealtimePreviewDynamic.tsx
@@ -592,10 +592,10 @@ const RealtimePreviewDynamicComponent: React.FC<RealtimePreviewProps> = ({
       isResizing ? "none" :
       isOnSplitPanel ? (isDraggingSplitPanel ? "none" : "left 0.15s ease-out, width 0.15s ease-out") : undefined,
   } : {
-    // 런타임 모드: 부모(ResponsiveGridRenderer)가 위치/너비 관리
+    // 런타임 모드: CSS scale 기반 - 캔버스 픽셀 크기 그대로 사용, 부모가 scale()로 축소
     ...safeComponentStyle,
     width: "100%",
-    height: displayHeight,
+    height: "100%",
     position: "relative" as const,
   };
 
diff --git a/frontend/components/screen/ResponsiveGridRenderer.tsx b/frontend/components/screen/ResponsiveGridRenderer.tsx
index 1322ee99..d90a0667 100644
--- a/frontend/components/screen/ResponsiveGridRenderer.tsx
+++ b/frontend/components/screen/ResponsiveGridRenderer.tsx
@@ -23,8 +23,9 @@ function getComponentTypeId(component: ComponentData): string {
 }
 
 /**
- * 디자이너 절대좌표를 캔버스 대비 비율로 변환하여 렌더링.
- * 화면이 줄어들면 비율에 맞게 축소, 늘어나면 확대.
+ * CSS transform scale 기반 렌더링.
+ * 디자이너와 동일하게 캔버스 해상도(px)로 레이아웃 후 CSS scale로 축소/확대.
+ * 텍스트, 패딩, 버튼 등 모든 요소가 균일하게 스케일링되어 WYSIWYG 보장.
  */
 function ProportionalRenderer({
   components,
@@ -47,7 +48,7 @@ function ProportionalRenderer({
   }, []);
 
   const topLevel = components.filter((c) => !c.parentId);
-  const ratio = containerW > 0 ? containerW / canvasWidth : 1;
+  const scale = containerW > 0 ? containerW / canvasWidth : 1;
 
   const maxBottom = topLevel.reduce((max, c) => {
     const bottom = c.position.y + (c.size?.height || 40);
@@ -58,30 +59,41 @@ function ProportionalRenderer({
     <div
       ref={containerRef}
       data-screen-runtime="true"
-      className="bg-background relative w-full overflow-x-hidden"
-      style={{ minHeight: containerW > 0 ? `${maxBottom * ratio}px` : "200px" }}
+      className="bg-background w-full overflow-hidden"
+      style={{ height: containerW > 0 ? `${maxBottom * scale}px` : "200px" }}
     >
-      {containerW > 0 &&
-        topLevel.map((component) => {
-          const typeId = getComponentTypeId(component);
-          return (
-            <div
-              key={component.id}
-              data-component-id={component.id}
-              data-component-type={typeId}
-              style={{
-                position: "absolute",
-                left: `${(component.position.x / canvasWidth) * 100}%`,
-                top: `${component.position.y * ratio}px`,
-                width: `${((component.size?.width || 100) / canvasWidth) * 100}%`,
-                height: `${(component.size?.height || 40) * ratio}px`,
-                zIndex: component.position.z || 1,
-              }}
-            >
-              {renderComponent(component)}
-            </div>
-          );
-        })}
+      {containerW > 0 && (
+        <div
+          style={{
+            width: `${canvasWidth}px`,
+            height: `${maxBottom}px`,
+            transform: `scale(${scale})`,
+            transformOrigin: "top left",
+            position: "relative",
+          }}
+        >
+          {topLevel.map((component) => {
+            const typeId = getComponentTypeId(component);
+            return (
+              <div
+                key={component.id}
+                data-component-id={component.id}
+                data-component-type={typeId}
+                style={{
+                  position: "absolute",
+                  left: `${component.position.x}px`,
+                  top: `${component.position.y}px`,
+                  width: `${component.size?.width || 100}px`,
+                  height: `${component.size?.height || 40}px`,
+                  zIndex: component.position.z || 1,
+                }}
+              >
+                {renderComponent(component)}
+              </div>
+            );
+          })}
+        </div>
+      )}
     </div>
   );
 }
diff --git a/frontend/lib/registry/components/v2-split-panel-layout/SplitPanelLayoutComponent.tsx b/frontend/lib/registry/components/v2-split-panel-layout/SplitPanelLayoutComponent.tsx
index 8467154a..fc244a3d 100644
--- a/frontend/lib/registry/components/v2-split-panel-layout/SplitPanelLayoutComponent.tsx
+++ b/frontend/lib/registry/components/v2-split-panel-layout/SplitPanelLayoutComponent.tsx
@@ -2522,9 +2522,11 @@ export const SplitPanelLayoutComponent: React.FC<SplitPanelLayoutComponentProps>
 
   // 우측 패널 컬럼 헤더 드래그 (디자인 모드에서 컬럼 순서 변경)
   const handleRightColumnDragStart = useCallback(
-    (columnIndex: number, source: "main" | number) => {
+    (e: React.DragEvent, columnIndex: number, source: "main" | number) => {
       setRightDraggedColumnIndex(columnIndex);
       setRightDragSource(source);
+      e.dataTransfer.effectAllowed = "move";
+      e.dataTransfer.setData("text/plain", `col-${source}-${columnIndex}`);
     },
     [],
   );
@@ -4181,7 +4183,7 @@ export const SplitPanelLayoutComponent: React.FC<SplitPanelLayoutComponentProps>
                                     isDragging && "opacity-50",
                                   )}
                                   draggable={canDragTabColumns}
-                                  onDragStart={() => canDragTabColumns && handleRightColumnDragStart(idx, tabIndex)}
+                                  onDragStart={(e) => canDragTabColumns && handleRightColumnDragStart(e, idx, tabIndex)}
                                   onDragOver={(e) => canDragTabColumns && handleRightColumnDragOver(e, idx)}
                                   onDragEnd={handleRightColumnDragEnd}
                                   onDrop={(e) => canDragTabColumns && handleRightColumnDrop(e, idx, tabIndex)}
@@ -4318,7 +4320,7 @@ export const SplitPanelLayoutComponent: React.FC<SplitPanelLayoutComponentProps>
                                     isDragging && "opacity-50",
                                   )}
                                   draggable={canDragListTabColumns}
-                                  onDragStart={() => canDragListTabColumns && handleRightColumnDragStart(idx, listTabIndex)}
+                                  onDragStart={(e) => canDragListTabColumns && handleRightColumnDragStart(e, idx, listTabIndex)}
                                   onDragOver={(e) => canDragListTabColumns && handleRightColumnDragOver(e, idx)}
                                   onDragEnd={handleRightColumnDragEnd}
                                   onDrop={(e) => canDragListTabColumns && handleRightColumnDrop(e, idx, listTabIndex)}
@@ -4745,7 +4747,7 @@ export const SplitPanelLayoutComponent: React.FC<SplitPanelLayoutComponentProps>
                                         textAlign: col.align || "left",
                                       }}
                                       draggable={isDraggable}
-                                      onDragStart={() => isDraggable && handleRightColumnDragStart(configColIndex, "main")}
+                                      onDragStart={(e) => isDraggable && handleRightColumnDragStart(e, configColIndex, "main")}
                                       onDragOver={(e) => isDraggable && handleRightColumnDragOver(e, configColIndex)}
                                       onDragEnd={handleRightColumnDragEnd}
                                       onDrop={(e) => isDraggable && handleRightColumnDrop(e, configColIndex, "main")}