diff --git a/src/components/SideBar.tsx b/src/components/SideBar.tsx
index 9622f08..a351b38 100644
--- a/src/components/SideBar.tsx
+++ b/src/components/SideBar.tsx
@@ -126,6 +126,7 @@ export function SideBar() {
           })}
           baseSize={baseSize}
           onLeave={sidebarToggleMode === 'float' ? () => setShowSideBar(false) : undefined}
+          sizeVariableMountPoint={sidebarToggleMode === 'persistent' ? document.body : undefined}
         >
           <div className={'gitako-side-bar-body'}>
             <div
diff --git a/src/components/SideBarBodyWrapper.tsx b/src/components/SideBarBodyWrapper.tsx
index d0b1c10..fe9ce13 100644
--- a/src/components/SideBarBodyWrapper.tsx
+++ b/src/components/SideBarBodyWrapper.tsx
@@ -4,25 +4,32 @@ import * as React from 'react'
 import { useDebounce, useWindowSize } from 'react-use'
 import { defaultConfigs } from 'utils/config/helper'
 import { cx } from 'utils/cx'
-import { setResizingState } from 'utils/DOMHelper'
+import { setCSSVariable } from 'utils/DOMHelper'
 import * as features from 'utils/features'
-import { useCSSVariable } from 'utils/hooks/useCSSVariable'
 
 export type Size = number
 type Props = {
   baseSize: Size
   className?: string
   onLeave?: React.HTMLAttributes<HTMLElement>['onMouseLeave']
+  sizeVariableMountPoint?: HTMLElement
 }
 
 const MINIMAL_CONTENT_VIEWPORT_WIDTH = 100
 const MINIMAL_WIDTH = 240
 
+function getSafeSize(size: number, width: number) {
+  if (size > width - MINIMAL_CONTENT_VIEWPORT_WIDTH) return width - MINIMAL_CONTENT_VIEWPORT_WIDTH
+  if (size < MINIMAL_WIDTH) return MINIMAL_WIDTH
+  return size
+}
+
 export function SideBarBodyWrapper({
   baseSize,
   className,
   children,
   onLeave,
+  sizeVariableMountPoint,
 }: React.PropsWithChildren<Props>) {
   const [size, setSize] = React.useState(baseSize)
   const configContext = useConfigs()
@@ -34,27 +41,50 @@ export function SideBarBodyWrapper({
 
   const { width } = useWindowSize()
   React.useEffect(() => {
-    if (size > width - MINIMAL_CONTENT_VIEWPORT_WIDTH)
-      setSize(width - MINIMAL_CONTENT_VIEWPORT_WIDTH)
-    else if (size < MINIMAL_WIDTH) setSize(MINIMAL_WIDTH)
+    const safeSize = getSafeSize(size, width)
+    if (safeSize !== size) setSize(safeSize)
   }, [width, size])
-
-  React.useEffect(() => {
-    setResizingState(true)
-    const timer = setTimeout(() => setResizingState(false), 100)
-    return () => clearTimeout(timer)
-  }, [width, size])
-
-  useCSSVariable('--gitako-width', `${size}px`)
+  const bodyWrapperRef = React.useRef<HTMLDivElement | null>(null)
   useDebounce(() => configContext.onChange({ sideBarWidth: size }), 100, [size])
 
-  const onResize = React.useCallback((size: number) => {
-    // do NOT merge this with the above similar effect, side bar will jump otherwise
-    if (size > width - MINIMAL_CONTENT_VIEWPORT_WIDTH)
-      setSize(width - MINIMAL_CONTENT_VIEWPORT_WIDTH)
-    else if (size < MINIMAL_WIDTH) setSize(MINIMAL_WIDTH)
-    else setSize(size)
-  }, [])
+  function apply(sizeVariableMountPoint: HTMLElement | undefined, size: number) {
+    if (sizeVariableMountPoint)
+      setCSSVariable(
+        '--gitako-width',
+        sizeVariableMountPoint ? `${size}px` : undefined,
+        sizeVariableMountPoint,
+      )
+
+    if (bodyWrapperRef.current)
+      setCSSVariable(
+        '--gitako-width',
+        sizeVariableMountPoint ? undefined : `${size}px`,
+        bodyWrapperRef.current,
+      )
+  }
+
+  // Update size using useEffect would cause delay
+  const onResize = React.useMemo(() => {
+    let sizeToApply: number,
+      applied = true
+    return (size: number) => {
+      // do NOT merge this with the above similar effect, side bar will jump otherwise
+      sizeToApply = getSafeSize(size, width)
+      setSize(sizeToApply)
+
+      if (applied) {
+        applied = false
+        requestAnimationFrame(() => {
+          applied = true
+          apply(sizeVariableMountPoint, sizeToApply)
+        })
+      }
+    }
+  }, [width, sizeVariableMountPoint])
+
+  React.useEffect(() => {
+    apply(sizeVariableMountPoint, size)
+  }, [sizeVariableMountPoint])
 
   const onMouseLeave = React.useCallback(
     e => {
@@ -65,7 +95,11 @@ export function SideBarBodyWrapper({
   )
 
   return (
-    <div className={cx('gitako-side-bar-body-wrapper', className)} onMouseLeave={onMouseLeave}>
+    <div
+      ref={bodyWrapperRef}
+      className={cx('gitako-side-bar-body-wrapper', className)}
+      onMouseLeave={onMouseLeave}
+    >
       <div className={'gitako-side-bar-body-wrapper-content'}>{children}</div>
       {features.resize && (
         <HorizontalResizeHandler
diff --git a/src/styles/index.scss b/src/styles/index.scss
index 6f16af6..4f11413 100644
--- a/src/styles/index.scss
+++ b/src/styles/index.scss
@@ -81,9 +81,6 @@ $minimal-z-index: max($github-header-z-index, $github-pull-request-float-header-
   }
 }
 
-:root {
-  --gitako-width: #{$side-bar-base-width};
-}
 
 .#{$name}-ready {
   // github
diff --git a/src/utils/DOMHelper.ts b/src/utils/DOMHelper.ts
index f117275..94ddee9 100644
--- a/src/utils/DOMHelper.ts
+++ b/src/utils/DOMHelper.ts
@@ -123,15 +123,13 @@ export function focusSearchInput() {
   })
 }
 
-export function setResizingState(on: boolean) {
-  const target = document.querySelector('.gitako-toggle-show-button-wrapper')
-  if (!target) return
-  if (on) target.classList.add('resizing')
-  else target.classList.remove('resizing')
-}
-
-export function findNodeElement(node:TreeNode, rootElement: HTMLElement): HTMLElement | null {
+export function findNodeElement(node: TreeNode, rootElement: HTMLElement): HTMLElement | null {
   const nodeElement = rootElement.querySelector(`a[href="${node.url}"]`)
   if (nodeElement instanceof HTMLElement) return nodeElement
   return null
 }
+
+export function setCSSVariable(name: string, value: string | undefined, element: HTMLElement) {
+  if (value === undefined) element.style.removeProperty(name)
+  else element.style.setProperty(name, value)
+}