diff --git a/frontend/components/common/ResponsiveSplitPanel.tsx b/frontend/components/common/ResponsiveSplitPanel.tsx
index 860254a1..7b0f6031 100644
--- a/frontend/components/common/ResponsiveSplitPanel.tsx
+++ b/frontend/components/common/ResponsiveSplitPanel.tsx
@@ -6,36 +6,45 @@ import { Button } from "@/components/ui/button";
 import { cn } from "@/lib/utils";
 
 export interface ResponsiveSplitPanelProps {
-  /** 좌측 패널 콘텐츠 */
   left: ReactNode;
-  /** 우측 패널 콘텐츠 */
   right: ReactNode;
 
-  /** 좌측 패널 제목 (모바일 접기/펼치기 시 표시) */
   leftTitle?: string;
-  /** 좌측 패널 기본 너비 (%, 기본: 25) */
   leftWidth?: number;
-  /** 좌측 패널 최소 너비 (%, 기본: 10) */
   minLeftWidth?: number;
-  /** 좌측 패널 최대 너비 (%, 기본: 50) */
   maxLeftWidth?: number;
 
-  /** 리사이저 표시 여부 (기본: true) */
   showResizer?: boolean;
-  /** 모바일에서 좌측 패널 기본 접힘 여부 (기본: true) */
   collapsedOnMobile?: boolean;
 
-  /** 컨테이너 높이 (기본: "100%") */
   height?: string;
-  /** 추가 className */
   className?: string;
-  /** 좌측 패널 추가 className */
   leftClassName?: string;
-  /** 우측 패널 추가 className */
   rightClassName?: string;
 }
 
-const MOBILE_BREAKPOINT = 1024;
+type ViewMode = "desktop" | "tablet" | "mobile";
+
+const DESKTOP_BREAKPOINT = 1280;
+const TABLET_BREAKPOINT = 768;
+
+function getViewMode(width: number): ViewMode {
+  if (width >= DESKTOP_BREAKPOINT) return "desktop";
+  if (width >= TABLET_BREAKPOINT) return "tablet";
+  return "mobile";
+}
+
+function getAdaptiveLeftWidth(
+  baseWidth: number,
+  containerWidth: number,
+  minPx: number
+): number {
+  const currentPx = (baseWidth / 100) * containerWidth;
+  if (currentPx < minPx) {
+    return Math.min((minPx / containerWidth) * 100, 50);
+  }
+  return baseWidth;
+}
 
 export function ResponsiveSplitPanel({
   left,
@@ -51,28 +60,76 @@ export function ResponsiveSplitPanel({
   leftClassName,
   rightClassName,
 }: ResponsiveSplitPanelProps) {
-  const [leftWidth, setLeftWidth] = useState(initialLeftWidth);
-  const [isMobileView, setIsMobileView] = useState(false);
+  const [userLeftWidth, setUserLeftWidth] = useState(initialLeftWidth);
+  const [viewMode, setViewMode] = useState<ViewMode>("desktop");
   const [leftCollapsed, setLeftCollapsed] = useState(false);
+  const [containerWidth, setContainerWidth] = useState(0);
   const containerRef = useRef<HTMLDivElement>(null);
   const isDraggingRef = useRef(false);
+  const prevViewModeRef = useRef<ViewMode>("desktop");
 
-  // 뷰포트 감지
+  // 컨테이너 크기 + 뷰 모드 실시간 감지
   useEffect(() => {
-    const checkMobile = () => {
-      const mobile = window.innerWidth < MOBILE_BREAKPOINT;
-      setIsMobileView(mobile);
-      if (mobile && collapsedOnMobile) {
-        setLeftCollapsed(true);
-      }
-    };
+    const container = containerRef.current;
+    if (!container) return;
 
-    checkMobile();
-    window.addEventListener("resize", checkMobile);
-    return () => window.removeEventListener("resize", checkMobile);
+    const observer = new ResizeObserver((entries) => {
+      const entry = entries[0];
+      if (!entry) return;
+      const w = entry.contentRect.width;
+      setContainerWidth(w);
+
+      const newMode = getViewMode(window.innerWidth);
+      setViewMode((prev) => {
+        if (prev !== newMode) {
+          if (newMode === "mobile" && collapsedOnMobile) {
+            setLeftCollapsed(true);
+          } else if (newMode === "tablet") {
+            setLeftCollapsed(true);
+          } else if (newMode === "desktop" && prev !== "desktop") {
+            setLeftCollapsed(false);
+          }
+        }
+        return newMode;
+      });
+    });
+
+    observer.observe(container);
+    setContainerWidth(container.offsetWidth);
+    const initialMode = getViewMode(window.innerWidth);
+    setViewMode(initialMode);
+    if (initialMode === "mobile" && collapsedOnMobile) {
+      setLeftCollapsed(true);
+    } else if (initialMode === "tablet") {
+      setLeftCollapsed(true);
+    }
+
+    return () => observer.disconnect();
   }, [collapsedOnMobile]);
 
-  // 데스크톱 리사이저
+  // window resize도 감지 (viewport 변화)
+  useEffect(() => {
+    const handleResize = () => {
+      const newMode = getViewMode(window.innerWidth);
+      setViewMode((prev) => {
+        if (prev !== newMode) {
+          if (newMode === "mobile" && collapsedOnMobile) {
+            setLeftCollapsed(true);
+          } else if (newMode === "tablet") {
+            setLeftCollapsed(true);
+          } else if (newMode === "desktop") {
+            setLeftCollapsed(false);
+          }
+        }
+        return newMode;
+      });
+    };
+
+    window.addEventListener("resize", handleResize);
+    return () => window.removeEventListener("resize", handleResize);
+  }, [collapsedOnMobile]);
+
+  // 리사이저
   const handleMouseDown = useCallback(() => {
     isDraggingRef.current = true;
     document.body.style.cursor = "col-resize";
@@ -85,7 +142,7 @@ export function ResponsiveSplitPanel({
       const rect = containerRef.current.getBoundingClientRect();
       const pct = ((e.clientX - rect.left) / rect.width) * 100;
       if (pct >= minLeftWidth && pct <= maxLeftWidth) {
-        setLeftWidth(pct);
+        setUserLeftWidth(pct);
       }
     },
     [minLeftWidth, maxLeftWidth]
@@ -106,11 +163,17 @@ export function ResponsiveSplitPanel({
     };
   }, [handleMouseMove, handleMouseUp]);
 
-  // --- 모바일 레이아웃: 세로 스택 ---
-  if (isMobileView) {
+  // 좌측 패널 최소 px 보장 (200px 이하로 줄어들지 않게)
+  const MIN_LEFT_PX = 200;
+  const effectiveLeftWidth =
+    containerWidth > 0
+      ? getAdaptiveLeftWidth(userLeftWidth, containerWidth, MIN_LEFT_PX)
+      : userLeftWidth;
+
+  // --- 모바일: 세로 스택 ---
+  if (viewMode === "mobile") {
     return (
-      <div className={cn("flex flex-col gap-0", className)} style={{ height }}>
-        {/* 좌측 패널 토글 헤더 */}
+      <div ref={containerRef} className={cn("flex flex-col gap-0", className)} style={{ height }}>
         <button
           onClick={() => setLeftCollapsed(!leftCollapsed)}
           className={cn(
@@ -127,19 +190,12 @@ export function ResponsiveSplitPanel({
           )}
         </button>
 
-        {/* 좌측 패널 (접기/펼치기) */}
         {!leftCollapsed && (
-          <div
-            className={cn(
-              "max-h-[40vh] overflow-y-auto border-b",
-              leftClassName
-            )}
-          >
+          <div className={cn("max-h-[40vh] overflow-y-auto border-b", leftClassName)}>
             {left}
           </div>
         )}
 
-        {/* 우측 패널 (항상 표시) */}
         <div className={cn("min-h-0 flex-1 overflow-y-auto", rightClassName)}>
           {right}
         </div>
@@ -147,39 +203,42 @@ export function ResponsiveSplitPanel({
     );
   }
 
-  // --- 데스크톱 레이아웃: 좌우 분할 ---
+  // --- 태블릿 + 데스크톱: 좌우 분할 ---
   return (
     <div
       ref={containerRef}
       className={cn("flex gap-0 overflow-hidden", className)}
       style={{ height }}
     >
-      {/* 좌측 패널 (접기 가능) */}
+      {/* 좌측 패널 */}
       {!leftCollapsed ? (
         <>
           <div
-            style={{ width: `${leftWidth}%` }}
-            className={cn("flex h-full flex-col overflow-hidden pr-3", leftClassName)}
+            style={{ width: `${effectiveLeftWidth}%` }}
+            className={cn(
+              "flex h-full flex-col overflow-hidden border-r pr-1 transition-[width] duration-200",
+              leftClassName
+            )}
           >
             <div className="flex-1 overflow-y-auto">{left}</div>
           </div>
 
-          {/* 리사이저 */}
-          {showResizer && (
+          {/* 리사이저 (데스크톱만) */}
+          {showResizer && viewMode === "desktop" && (
             <div
               onMouseDown={handleMouseDown}
-              className="group hover:bg-accent/50 relative flex h-full w-3 shrink-0 cursor-col-resize items-center justify-center border-r transition-colors"
+              className="group hover:bg-accent/50 relative flex h-full w-2 shrink-0 cursor-col-resize items-center justify-center transition-colors"
             >
               <GripVertical className="text-muted-foreground group-hover:text-foreground h-4 w-4 transition-colors" />
             </div>
           )}
         </>
       ) : (
-        <div className="flex h-full w-8 shrink-0 items-start justify-center border-r pt-2">
+        <div className="flex h-full w-10 shrink-0 flex-col items-center border-r pt-2">
           <Button
             variant="ghost"
             size="icon"
-            className="h-6 w-6"
+            className="h-7 w-7"
             onClick={() => setLeftCollapsed(false)}
             title={`${leftTitle} 열기`}
           >
@@ -191,11 +250,15 @@ export function ResponsiveSplitPanel({
       {/* 우측 패널 */}
       <div
         style={{
-          width: leftCollapsed ? "calc(100% - 32px)" : `${100 - leftWidth - 1}%`,
+          width: leftCollapsed
+            ? "calc(100% - 40px)"
+            : `${100 - effectiveLeftWidth}%`,
         }}
-        className={cn("flex h-full flex-col overflow-hidden pl-3", rightClassName)}
+        className={cn(
+          "flex h-full flex-col overflow-hidden pl-2 transition-[width] duration-200",
+          rightClassName
+        )}
       >
-        {/* 데스크톱 접기 버튼 */}
         {!leftCollapsed && (
           <div className="mb-1 flex justify-start">
             <Button
diff --git a/frontend/components/screen/ResponsiveGridRenderer.tsx b/frontend/components/screen/ResponsiveGridRenderer.tsx
index daaa6d75..8f671c21 100644
--- a/frontend/components/screen/ResponsiveGridRenderer.tsx
+++ b/frontend/components/screen/ResponsiveGridRenderer.tsx
@@ -1,6 +1,6 @@
 "use client";
 
-import React, { useMemo, useRef, useState, useEffect } from "react";
+import React, { useRef, useState, useEffect } from "react";
 import { ComponentData } from "@/types/screen";
 import { useResponsive } from "@/lib/hooks/useResponsive";
 import { cn } from "@/lib/utils";
@@ -111,11 +111,6 @@ interface ProcessedRow {
   normalComps: ComponentData[];
 }
 
-/**
- * 풀위드스 컴포넌트 + 오버레이 버튼.
- * 원본 좌표 그대로 배치 → transform: scale 한 방으로 축소.
- * 디자이너 미리보기와 동일한 원리.
- */
 function FullWidthOverlayRow({
   main,
   overlayComps,
@@ -150,8 +145,6 @@ function FullWidthOverlayRow({
   const maxBtnH = Math.max(
     ...overlayComps.map((c) => c.size?.height || 40)
   );
-  // 버튼 중심 보정: 스케일 축소 시 버튼이 작아지므로 중심 위치가 위로 올라감
-  // 디자이너와 동일한 중심-대-중심 정렬을 유지하기 위해 Y 오프셋 보정
   const yOffset = rawYOffset + (maxBtnH / 2) * (1 - scale);
 
   return (
@@ -209,144 +202,57 @@ function FullWidthOverlayRow({
   );
 }
 
-/**
- * 데스크톱: 원본 캔버스 좌표 기반 렌더링 (transform: scale 로 축소)
- * 디자이너에서 설계한 레이아웃을 그대로 유지하면서 뷰포트에 맞춤
- */
-function DesktopCanvasRenderer({
-  components,
-  canvasWidth,
-  canvasHeight,
-  renderComponent,
-}: ResponsiveGridRendererProps) {
-  const containerRef = useRef<HTMLDivElement>(null);
-  const [containerW, setContainerW] = useState(0);
-
-  useEffect(() => {
-    const el = containerRef.current;
-    if (!el) return;
-    const ro = new ResizeObserver((entries) => {
-      const w = entries[0]?.contentRect.width;
-      if (w && w > 0) setContainerW(w);
-    });
-    ro.observe(el);
-    return () => ro.disconnect();
-  }, []);
-
-  const topLevel = components.filter((c) => !c.parentId);
-  const scale = containerW > 0 ? Math.min(containerW / canvasWidth, 1) : 1;
-  const scaledHeight = canvasHeight * scale;
-
-  return (
-    <div
-      ref={containerRef}
-      data-screen-runtime="true"
-      className="bg-background relative w-full overflow-x-hidden"
-      style={{ minHeight: `${scaledHeight}px` }}
-    >
-      <div
-        style={{
-          width: `${canvasWidth}px`,
-          height: `${canvasHeight}px`,
-          transform: `scale(${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 ? `${component.size.width}px` : "auto",
-                height: component.size?.height ? `${component.size.height}px` : "auto",
-                zIndex: component.position.z || 1,
-              }}
-            >
-              {renderComponent(component)}
-            </div>
-          );
-        })}
-      </div>
-    </div>
-  );
-}
-
 export function ResponsiveGridRenderer({
   components,
   canvasWidth,
   canvasHeight,
   renderComponent,
 }: ResponsiveGridRendererProps) {
-  const { isMobile, isTablet } = useResponsive();
+  const { isMobile } = useResponsive();
 
-  // 데스크톱: 원본 캔버스 좌표 유지 (스케일링)
-  // 풀위드스 컴포넌트(테이블, 스플릿패널 등)가 있으면 flex 레이아웃 사용
   const topLevel = components.filter((c) => !c.parentId);
-  const hasFullWidthComponent = topLevel.some((c) => isFullWidthComponent(c));
-  const useCanvasLayout = !isMobile && !isTablet && !hasFullWidthComponent;
 
-  if (useCanvasLayout) {
-    return (
-      <DesktopCanvasRenderer
-        components={components}
-        canvasWidth={canvasWidth}
-        canvasHeight={canvasHeight}
-        renderComponent={renderComponent}
-      />
-    );
-  }
+  const rows = groupComponentsIntoRows(topLevel);
+  const processedRows: ProcessedRow[] = [];
 
-  const processedRows = useMemo(() => {
-    const rows = groupComponentsIntoRows(topLevel);
+  for (const row of rows) {
+    const fullWidthComps: ComponentData[] = [];
+    const normalComps: ComponentData[] = [];
 
-    const result: ProcessedRow[] = [];
-    for (const row of rows) {
-      const fullWidthComps: ComponentData[] = [];
-      const normalComps: ComponentData[] = [];
-
-      for (const comp of row) {
-        if (isFullWidthComponent(comp)) {
-          fullWidthComps.push(comp);
-        } else {
-          normalComps.push(comp);
-        }
-      }
-
-      if (fullWidthComps.length > 0 && normalComps.length > 0) {
-        for (const fwComp of fullWidthComps) {
-          result.push({
-            type: "fullwidth",
-            mainComponent: fwComp,
-            overlayComps: normalComps,
-            normalComps: [],
-          });
-        }
-      } else if (fullWidthComps.length > 0) {
-        for (const fwComp of fullWidthComps) {
-          result.push({
-            type: "fullwidth",
-            mainComponent: fwComp,
-            overlayComps: [],
-            normalComps: [],
-          });
-        }
+    for (const comp of row) {
+      if (isFullWidthComponent(comp)) {
+        fullWidthComps.push(comp);
       } else {
-        result.push({
-          type: "normal",
-          overlayComps: [],
-          normalComps,
-        });
+        normalComps.push(comp);
       }
     }
-    return result;
-  }, [topLevel]);
+
+    if (fullWidthComps.length > 0 && normalComps.length > 0) {
+      for (const fwComp of fullWidthComps) {
+        processedRows.push({
+          type: "fullwidth",
+          mainComponent: fwComp,
+          overlayComps: normalComps,
+          normalComps: [],
+        });
+      }
+    } else if (fullWidthComps.length > 0) {
+      for (const fwComp of fullWidthComps) {
+        processedRows.push({
+          type: "fullwidth",
+          mainComponent: fwComp,
+          overlayComps: [],
+          normalComps: [],
+        });
+      }
+    } else {
+      processedRows.push({
+        type: "normal",
+        overlayComps: [],
+        normalComps,
+      });
+    }
+  }
 
   return (
     <div
@@ -371,12 +277,18 @@ export function ResponsiveGridRenderer({
         const allButtons = normalComps.every((c) => isButtonComponent(c));
         const gap = isMobile ? 8 : allButtons ? 8 : getRowGap(normalComps, canvasWidth);
 
+        const hasFlexHeightComp = normalComps.some((c) => {
+          const h = c.size?.height || 0;
+          return h / canvasHeight >= 0.8;
+        });
+
         return (
           <div
             key={`row-${rowIndex}`}
             className={cn(
-              "flex w-full flex-shrink-0 flex-wrap overflow-hidden",
-              allButtons && "justify-end px-2 py-1"
+              "flex w-full flex-wrap overflow-hidden",
+              allButtons && "justify-end px-2 py-1",
+              hasFlexHeightComp ? "min-h-0 flex-1" : "flex-shrink-0"
             )}
             style={{ gap: `${gap}px` }}
           >
@@ -409,22 +321,26 @@ export function ResponsiveGridRenderer({
               const flexBasis = isFullWidth
                 ? "100%"
                 : `calc(${percentWidth}% - ${gap}px)`;
-              const compFlexGrow = shouldFlexGrow(component);
+
+              const heightPct = (component.size?.height || 0) / canvasHeight;
+              const useFlexHeight = heightPct >= 0.8;
 
               return (
                 <div
                   key={component.id}
                   data-component-id={component.id}
                   data-component-type={typeId}
-                  className="min-w-0 flex-shrink-0 overflow-hidden"
+                  className={cn("min-w-0 overflow-hidden", useFlexHeight && "min-h-0 flex-1")}
                   style={{
                     width: isFullWidth ? "100%" : undefined,
-                    flexBasis,
-                    flexGrow: isFullWidth || compFlexGrow ? 1 : 0,
+                    flexBasis: useFlexHeight ? undefined : flexBasis,
+                    flexGrow: 1,
+                    flexShrink: 1,
                     minWidth: isMobile ? "100%" : undefined,
-                    height: component.size?.height
+                    minHeight: useFlexHeight ? "300px" : undefined,
+                    height: useFlexHeight ? "100%" : (component.size?.height
                       ? `${component.size.height}px`
-                      : "auto",
+                      : "auto"),
                   }}
                 >
                   {renderComponent(component)}
diff --git a/frontend/lib/registry/DynamicComponentRenderer.tsx b/frontend/lib/registry/DynamicComponentRenderer.tsx
index 6e0b281c..03b05206 100644
--- a/frontend/lib/registry/DynamicComponentRenderer.tsx
+++ b/frontend/lib/registry/DynamicComponentRenderer.tsx
@@ -662,11 +662,15 @@ export const DynamicComponentRenderer: React.FC<DynamicComponentRendererProps> =
           return null;
         }
 
-        // size.width와 size.height를 style.width와 style.height로 변환
+        const isRuntimeMode = !(props.isDesignMode);
         const finalStyle: React.CSSProperties = {
           ...component.style,
-          width: component.size?.width ? `${component.size.width}px` : component.style?.width,
-          height: component.size?.height ? `${component.size.height}px` : component.style?.height,
+          width: isRuntimeMode
+            ? "100%"
+            : (component.size?.width ? `${component.size.width}px` : component.style?.width),
+          height: isRuntimeMode
+            ? "100%"
+            : (component.size?.height ? `${component.size.height}px` : component.style?.height),
         };
 
         // 🆕 엔티티 검색 컴포넌트는 componentConfig.tableName을 사용해야 함 (화면 테이블이 아닌 검색 대상 테이블)