diff --git a/internal/tailwind-config/src/theme.css b/internal/tailwind-config/src/theme.css
index 2bf31bbe6..40e199fe6 100644
--- a/internal/tailwind-config/src/theme.css
+++ b/internal/tailwind-config/src/theme.css
@@ -310,6 +310,8 @@
   }
 
   html {
+    --vben-viewport-height: 100vh;
+
     @apply bg-background font-sans text-foreground;
 
     scroll-behavior: smooth;
@@ -320,6 +322,10 @@
     text-rendering: optimizelegibility;
     text-size-adjust: 100%;
     -webkit-tap-highlight-color: transparent;
+
+    @supports (height: 1dvh) {
+      --vben-viewport-height: 100dvh;
+    }
   }
 
   #app,
diff --git a/packages/@core/base/shared/src/constants/globals.ts b/packages/@core/base/shared/src/constants/globals.ts
index b86c45cd4..9e897fcae 100644
--- a/packages/@core/base/shared/src/constants/globals.ts
+++ b/packages/@core/base/shared/src/constants/globals.ts
@@ -6,6 +6,8 @@ export const CSS_VARIABLE_LAYOUT_CONTENT_WIDTH = `--vben-content-width`;
 export const CSS_VARIABLE_LAYOUT_HEADER_HEIGHT = `--vben-header-height`;
 /** layout footer 组件的高度 */
 export const CSS_VARIABLE_LAYOUT_FOOTER_HEIGHT = `--vben-footer-height`;
+/** layout overlay 使用的视口高度，CSS 按 100vh → 100dvh 降级 */
+export const CSS_VARIABLE_LAYOUT_VIEWPORT_HEIGHT = `--vben-viewport-height`;
 
 /** 内容区域的组件ID */
 export const ELEMENT_ID_MAIN_CONTENT = `__vben_main_content`;
diff --git a/packages/@core/composables/src/__tests__/use-layout-viewport-height.test.ts b/packages/@core/composables/src/__tests__/use-layout-viewport-height.test.ts
new file mode 100644
index 000000000..3fea8d342
--- /dev/null
+++ b/packages/@core/composables/src/__tests__/use-layout-viewport-height.test.ts
@@ -0,0 +1,139 @@
+import type { App } from 'vue';
+
+import { createApp } from 'vue';
+
+import { CSS_VARIABLE_LAYOUT_VIEWPORT_HEIGHT } from '@vben-core/shared/constants';
+
+import { afterEach, describe, expect, it, vi } from 'vitest';
+
+import { useLayoutViewportHeight } from '../use-layout-viewport-height';
+
+let activeApp: App | undefined;
+
+function stubDvhSupport(supported: boolean) {
+  vi.stubGlobal('CSS', {
+    supports: vi.fn((property: string, value: string) => {
+      return supported && property === 'height' && value === '1dvh';
+    }),
+  });
+}
+
+function mountViewportHeight() {
+  const host = document.createElement('div');
+  document.body.append(host);
+
+  activeApp = createApp({
+    setup() {
+      useLayoutViewportHeight();
+      return () => null;
+    },
+  });
+  activeApp.mount(host);
+}
+
+function getViewportHeightVar() {
+  return document.documentElement.style.getPropertyValue(
+    CSS_VARIABLE_LAYOUT_VIEWPORT_HEIGHT,
+  );
+}
+
+async function flushAnimationFrame() {
+  await new Promise<void>((resolve) => {
+    requestAnimationFrame(() => resolve());
+  });
+}
+
+afterEach(() => {
+  activeApp?.unmount();
+  activeApp = undefined;
+  document.body.innerHTML = '';
+  document.documentElement.style.removeProperty(
+    CSS_VARIABLE_LAYOUT_VIEWPORT_HEIGHT,
+  );
+  vi.unstubAllGlobals();
+  vi.restoreAllMocks();
+});
+
+describe('useLayoutViewportHeight', () => {
+  it('does not write the CSS variable when dvh is supported', () => {
+    const resizeObserver = vi.fn();
+    const addEventListener = vi.spyOn(window, 'addEventListener');
+    vi.stubGlobal('ResizeObserver', resizeObserver);
+    stubDvhSupport(true);
+
+    mountViewportHeight();
+
+    expect(getViewportHeightVar()).toBe('');
+    expect(resizeObserver).not.toHaveBeenCalled();
+    expect(addEventListener).not.toHaveBeenCalledWith(
+      'resize',
+      expect.any(Function),
+    );
+  });
+
+  it('writes innerHeight when dvh is unsupported', () => {
+    const resizeObserver = vi.fn();
+    vi.stubGlobal('ResizeObserver', resizeObserver);
+    stubDvhSupport(false);
+    vi.stubGlobal('visualViewport', null);
+    vi.spyOn(window, 'innerHeight', 'get').mockReturnValue(800);
+
+    mountViewportHeight();
+
+    expect(getViewportHeightVar()).toBe('800px');
+    expect(resizeObserver).not.toHaveBeenCalled();
+  });
+
+  it('prefers visualViewport.height over innerHeight', () => {
+    stubDvhSupport(false);
+    vi.spyOn(window, 'innerHeight', 'get').mockReturnValue(800);
+    const visualViewport = new EventTarget() as VisualViewport;
+    Object.defineProperty(visualViewport, 'height', {
+      configurable: true,
+      value: 640,
+      writable: true,
+    });
+    vi.stubGlobal('visualViewport', visualViewport);
+
+    mountViewportHeight();
+
+    expect(getViewportHeightVar()).toBe('640px');
+  });
+
+  it('updates the CSS variable on visualViewport resize and stops after unmount', async () => {
+    stubDvhSupport(false);
+    const visualViewport = new EventTarget() as VisualViewport;
+    Object.defineProperty(visualViewport, 'height', {
+      configurable: true,
+      value: 640,
+      writable: true,
+    });
+    vi.stubGlobal('visualViewport', visualViewport);
+
+    mountViewportHeight();
+    expect(getViewportHeightVar()).toBe('640px');
+
+    Object.defineProperty(visualViewport, 'height', {
+      configurable: true,
+      value: 520,
+      writable: true,
+    });
+    visualViewport.dispatchEvent(new Event('resize'));
+    await flushAnimationFrame();
+
+    expect(getViewportHeightVar()).toBe('520px');
+
+    activeApp?.unmount();
+    activeApp = undefined;
+
+    Object.defineProperty(visualViewport, 'height', {
+      configurable: true,
+      value: 400,
+      writable: true,
+    });
+    visualViewport.dispatchEvent(new Event('resize'));
+    await flushAnimationFrame();
+
+    expect(getViewportHeightVar()).toBe('520px');
+  });
+});
diff --git a/packages/@core/composables/src/index.ts b/packages/@core/composables/src/index.ts
index 2dbd4b807..8988cb87c 100644
--- a/packages/@core/composables/src/index.ts
+++ b/packages/@core/composables/src/index.ts
@@ -1,5 +1,6 @@
 export * from './use-is-mobile';
 export * from './use-layout-style';
+export * from './use-layout-viewport-height';
 export * from './use-namespace';
 export * from './use-priority-value';
 export * from './use-scroll-lock';
diff --git a/packages/@core/composables/src/use-layout-viewport-height.ts b/packages/@core/composables/src/use-layout-viewport-height.ts
new file mode 100644
index 000000000..c3c429661
--- /dev/null
+++ b/packages/@core/composables/src/use-layout-viewport-height.ts
@@ -0,0 +1,71 @@
+import { onMounted, onUnmounted } from 'vue';
+
+import { CSS_VARIABLE_LAYOUT_VIEWPORT_HEIGHT } from '@vben-core/shared/constants';
+
+import { useCssVar, useEventListener } from '@vueuse/core';
+
+function supportsDynamicViewportHeight() {
+  return (
+    globalThis.CSS !== undefined &&
+    typeof globalThis.CSS.supports === 'function' &&
+    globalThis.CSS.supports('height', '1dvh')
+  );
+}
+
+function readViewportHeight() {
+  return Math.round(window.visualViewport?.height ?? window.innerHeight);
+}
+
+/**
+ * 仅在不支持 dvh 时，把 --vben-viewport-height 写成像素值。
+ * 支持 dvh 时保持 CSS 的 100vh → 100dvh 级联，避免 useCssVar 把单位冻成 px。
+ */
+export function useLayoutViewportHeight() {
+  if (typeof window === 'undefined' || supportsDynamicViewportHeight()) {
+    return;
+  }
+
+  const viewportHeight = useCssVar(
+    CSS_VARIABLE_LAYOUT_VIEWPORT_HEIGHT,
+    document.documentElement,
+    { observe: false },
+  );
+
+  let frameId = 0;
+
+  function applyViewportHeight() {
+    viewportHeight.value = `${readViewportHeight()}px`;
+  }
+
+  function scheduleApplyViewportHeight() {
+    if (frameId) {
+      return;
+    }
+
+    frameId = window.requestAnimationFrame(() => {
+      frameId = 0;
+      applyViewportHeight();
+    });
+  }
+
+  applyViewportHeight();
+  onMounted(applyViewportHeight);
+  useEventListener(window, 'resize', scheduleApplyViewportHeight);
+
+  if (window.visualViewport) {
+    useEventListener(
+      window.visualViewport,
+      'resize',
+      scheduleApplyViewportHeight,
+    );
+  }
+
+  onUnmounted(() => {
+    if (!frameId) {
+      return;
+    }
+
+    window.cancelAnimationFrame(frameId);
+    frameId = 0;
+  });
+}
diff --git a/packages/@core/ui-kit/layout-ui/src/components/layout-content.vue b/packages/@core/ui-kit/layout-ui/src/components/layout-content.vue
index 3a04b71a6..78067f425 100644
--- a/packages/@core/ui-kit/layout-ui/src/components/layout-content.vue
+++ b/packages/@core/ui-kit/layout-ui/src/components/layout-content.vue
@@ -25,7 +25,7 @@ const props = withDefaults(defineProps<Props>(), {});
 
 const overlayViewportStyle: CSSProperties = {
   height:
-    'calc(100dvh - var(--vben-header-height, 0px) - var(--vben-footer-height, 0px))',
+    'calc(var(--vben-viewport-height) - var(--vben-header-height, 0px) - var(--vben-footer-height, 0px))',
 };
 
 const style = computed((): CSSProperties => {
@@ -65,6 +65,7 @@ const style = computed((): CSSProperties => {
     >
       <div
         :style="overlayViewportStyle"
+        data-layout-region="overlay-viewport"
         class="pointer-events-none relative min-h-0 w-full"
       >
         <slot name="overlay"></slot>
diff --git a/packages/@core/ui-kit/layout-ui/src/vben-layout.vue b/packages/@core/ui-kit/layout-ui/src/vben-layout.vue
index 4407d94e2..55f44c857 100644
--- a/packages/@core/ui-kit/layout-ui/src/vben-layout.vue
+++ b/packages/@core/ui-kit/layout-ui/src/vben-layout.vue
@@ -9,6 +9,7 @@ import {
   SCROLL_FIXED_CLASS,
   useLayoutFooterStyle,
   useLayoutHeaderStyle,
+  useLayoutViewportHeight,
 } from '@vben-core/composables';
 import { IconifyIcon } from '@vben-core/icons';
 import { VbenIconButton } from '@vben-core/shadcn-ui';
@@ -106,6 +107,7 @@ const {
   onScroll: handleLayoutScroll,
 });
 
+useLayoutViewportHeight();
 const { setLayoutHeaderHeight } = useLayoutHeaderStyle();
 const { setLayoutFooterHeight } = useLayoutFooterStyle();