diff --git a/src/renderer/src/App.tsx b/src/renderer/src/App.tsx
index 4fa2418fa50..989d7abb862 100644
--- a/src/renderer/src/App.tsx
+++ b/src/renderer/src/App.tsx
@@ -1,5 +1,5 @@
 /* eslint-disable max-lines */
-import { useEffect } from 'react'
+import { useEffect, useRef } from 'react'
 import { DEFAULT_WORKTREE_CARD_PROPERTIES } from '../../shared/constants'
 import { isGitRepoKind } from '../../shared/repo-kind'
 
@@ -29,6 +29,7 @@ import type { PersistedOpenFile } from '../../shared/types'
 import type { OpenFile } from './store/slices/editor'
 
 const isMac = navigator.userAgent.includes('Mac')
+const SIDEBAR_TRANSITION_MS = 200
 
 /** Build the editor-file portion of the workspace session for persistence.
  *  Only edit-mode files are saved — diffs and conflict views are transient. */
@@ -126,6 +127,7 @@ function App(): React.JSX.Element {
   const setRightSidebarTab = useAppStore((s) => s.setRightSidebarTab)
   const setQuickOpenVisible = useAppStore((s) => s.setQuickOpenVisible)
   const isFullScreen = useAppStore((s) => s.isFullScreen)
+  const hasSeenInitialSidebarStateRef = useRef(false)
 
   // Subscribe to IPC push events
   useIpcEvents()
@@ -299,6 +301,27 @@ function App(): React.JSX.Element {
     return () => window.removeEventListener('beforeunload', captureAndFlush)
   }, [])
 
+  useEffect(() => {
+    if (!persistedUIReady) {
+      return
+    }
+
+    if (!hasSeenInitialSidebarStateRef.current) {
+      hasSeenInitialSidebarStateRef.current = true
+      return
+    }
+
+    // Why: the terminal's WebGL renderer can flash blank while the app shell
+    // animates sidebar widths. Broadcasting the transition window lets active
+    // terminals temporarily fall back to the DOM renderer just for that
+    // animation, then restore GPU rendering after the layout settles.
+    window.dispatchEvent(
+      new CustomEvent('orca-layout-transition', {
+        detail: { durationMs: SIDEBAR_TRANSITION_MS }
+      })
+    )
+  }, [persistedUIReady, sidebarOpen, rightSidebarOpen])
+
   useEffect(() => {
     if (!persistedUIReady) {
       return
@@ -575,7 +598,11 @@ function App(): React.JSX.Element {
             {activeView === 'settings' ? <Settings /> : !activeWorktreeId ? <Landing /> : null}
           </div>
         </div>
-        {showSidebar && rightSidebarOpen ? <RightSidebar /> : null}
+        {/* Why: the right sidebar stays mounted even while "closed" so its
+            width can animate from 0px to the saved width. Unmounting here made
+            the panel pop in abruptly instead of matching the left sidebar's
+            smooth expand/collapse behavior. */}
+        {showSidebar ? <RightSidebar /> : null}
       </div>
       <QuickOpen />
       <ZoomOverlay />
diff --git a/src/renderer/src/components/right-sidebar/index.tsx b/src/renderer/src/components/right-sidebar/index.tsx
index 482f6961f2a..a3227964f30 100644
--- a/src/renderer/src/components/right-sidebar/index.tsx
+++ b/src/renderer/src/components/right-sidebar/index.tsx
@@ -138,15 +138,16 @@ export default function RightSidebar(): React.JSX.Element {
     : visibleItems[0].id
 
   const activityBarSideWidth = activityBarPosition === 'side' ? ACTIVITY_BAR_SIDE_WIDTH : 0
-  const { containerRef, isResizing, onResizeStart } = useSidebarResize<HTMLDivElement>({
-    isOpen: rightSidebarOpen,
-    width: rightSidebarWidth,
-    minWidth: MIN_WIDTH,
-    maxWidth: MAX_WIDTH,
-    deltaSign: -1,
-    renderedExtraWidth: activityBarSideWidth,
-    setWidth: setRightSidebarWidth
-  })
+  const { containerRef, onResizeStart, renderedOpen, contentAnimationState } =
+    useSidebarResize<HTMLDivElement>({
+      isOpen: rightSidebarOpen,
+      width: rightSidebarWidth,
+      minWidth: MIN_WIDTH,
+      maxWidth: MAX_WIDTH,
+      deltaSign: -1,
+      renderedExtraWidth: activityBarSideWidth,
+      setWidth: setRightSidebarWidth
+    })
 
   const panelContent = (
     <div className="flex flex-col flex-1 min-h-0 overflow-hidden scrollbar-sleek-parent">
@@ -171,54 +172,73 @@ export default function RightSidebar(): React.JSX.Element {
   return (
     <div
       ref={containerRef}
+      aria-hidden={!rightSidebarOpen}
       className={cn(
         'relative flex-shrink-0 flex flex-row overflow-visible',
-        isResizing ? 'transition-none' : 'transition-[width] duration-200'
+        !renderedOpen && 'pointer-events-none'
       )}
     >
       {/* Panel content area */}
       <div
         className="flex flex-col flex-1 min-w-0 bg-sidebar overflow-hidden"
         style={{
-          borderLeft: rightSidebarOpen ? '1px solid var(--sidebar-border)' : 'none'
+          borderLeft: renderedOpen ? '1px solid var(--sidebar-border)' : 'none'
         }}
       >
-        {activityBarPosition === 'top' ? (
-          /* ── Top activity bar: horizontal icon row ── */
-          <ContextMenu>
-            <ContextMenuTrigger asChild>
-              <div className="flex items-center border-b border-border h-[33px] min-h-[33px] px-1">
-                <TooltipProvider delayDuration={400}>{activityBarIcons}</TooltipProvider>
-              </div>
-            </ContextMenuTrigger>
-            <ActivityBarPositionMenu
-              currentPosition={activityBarPosition}
-              onChangePosition={setActivityBarPosition}
-            />
-          </ContextMenu>
-        ) : (
-          /* ── Side layout: static title header ── */
-          <div className="flex items-center h-[33px] min-h-[33px] px-3 border-b border-border">
-            <span className="text-[11px] font-semibold uppercase tracking-wider text-foreground">
-              {visibleItems.find((item) => item.id === effectiveTab)?.title ?? ''}
-            </span>
-          </div>
-        )}
+        <div
+          className={cn(
+            'flex min-h-0 flex-1 flex-col transition-[transform,opacity] duration-200 ease-out',
+            contentAnimationState === 'open' || contentAnimationState === 'opening'
+              ? 'translate-x-0 opacity-100'
+              : 'translate-x-3 opacity-0'
+          )}
+        >
+          {activityBarPosition === 'top' ? (
+            /* ── Top activity bar: horizontal icon row ── */
+            <ContextMenu>
+              <ContextMenuTrigger asChild>
+                <div className="flex items-center border-b border-border h-[33px] min-h-[33px] px-1">
+                  <TooltipProvider delayDuration={400}>{activityBarIcons}</TooltipProvider>
+                </div>
+              </ContextMenuTrigger>
+              <ActivityBarPositionMenu
+                currentPosition={activityBarPosition}
+                onChangePosition={setActivityBarPosition}
+              />
+            </ContextMenu>
+          ) : (
+            /* ── Side layout: static title header ── */
+            <div className="flex items-center h-[33px] min-h-[33px] px-3 border-b border-border">
+              <span className="text-[11px] font-semibold uppercase tracking-wider text-foreground">
+                {visibleItems.find((item) => item.id === effectiveTab)?.title ?? ''}
+              </span>
+            </div>
+          )}
 
-        {panelContent}
+          {panelContent}
+        </div>
 
         {/* Resize handle on LEFT side */}
-        <div
-          className="absolute top-0 left-0 w-1 h-full cursor-col-resize hover:bg-ring/20 active:bg-ring/30 transition-colors z-10"
-          onMouseDown={onResizeStart}
-        />
+        {renderedOpen ? (
+          <div
+            className="absolute top-0 left-0 w-1 h-full cursor-col-resize hover:bg-ring/20 active:bg-ring/30 transition-colors z-10"
+            onMouseDown={onResizeStart}
+          />
+        ) : null}
       </div>
 
       {/* Side Activity Bar (icon strip on right edge) — only for 'side' position */}
       {activityBarPosition === 'side' && (
         <ContextMenu>
           <ContextMenuTrigger asChild>
-            <div className="flex flex-col items-center w-10 min-w-[40px] bg-sidebar border-l border-border">
+            <div
+              className={cn(
+                'flex flex-col items-center w-10 min-w-[40px] bg-sidebar border-l border-border transition-[transform,opacity] duration-200 ease-out',
+                contentAnimationState === 'open' || contentAnimationState === 'opening'
+                  ? 'translate-x-0 opacity-100'
+                  : 'translate-x-3 opacity-0'
+              )}
+            >
               <TooltipProvider delayDuration={400}>{activityBarIcons}</TooltipProvider>
             </div>
           </ContextMenuTrigger>
diff --git a/src/renderer/src/components/sidebar/index.tsx b/src/renderer/src/components/sidebar/index.tsx
index fdf184e9065..b9eef83f899 100644
--- a/src/renderer/src/components/sidebar/index.tsx
+++ b/src/renderer/src/components/sidebar/index.tsx
@@ -33,43 +33,52 @@ export default function Sidebar(): React.JSX.Element {
     }
   }, [repoCount, fetchAllWorktrees])
 
-  const { containerRef, isResizing, onResizeStart } = useSidebarResize<HTMLDivElement>({
-    isOpen: sidebarOpen,
-    width: sidebarWidth,
-    minWidth: MIN_WIDTH,
-    maxWidth: MAX_WIDTH,
-    deltaSign: 1,
-    setWidth: setSidebarWidth
-  })
+  const { containerRef, onResizeStart, renderedOpen, contentAnimationState } =
+    useSidebarResize<HTMLDivElement>({
+      isOpen: sidebarOpen,
+      width: sidebarWidth,
+      minWidth: MIN_WIDTH,
+      maxWidth: MAX_WIDTH,
+      deltaSign: 1,
+      setWidth: setSidebarWidth
+    })
 
   return (
     <TooltipProvider delayDuration={400}>
       <div
         ref={containerRef}
-        className={cn(
-          'relative flex-shrink-0 bg-sidebar flex flex-col overflow-hidden scrollbar-sleek-parent',
-          isResizing ? 'transition-none' : 'transition-[width] duration-200'
-        )}
+        className="relative flex-shrink-0 bg-sidebar flex flex-col overflow-hidden scrollbar-sleek-parent"
         style={{
-          borderRight: sidebarOpen ? '1px solid var(--sidebar-border)' : 'none'
+          borderRight: renderedOpen ? '1px solid var(--sidebar-border)' : 'none'
         }}
       >
-        {/* Fixed controls */}
-        <SidebarHeader />
-        <SearchBar />
-        <GroupControls />
+        <div
+          className={cn(
+            'flex min-h-0 flex-1 flex-col transition-[transform,opacity] duration-200 ease-out',
+            contentAnimationState === 'open' || contentAnimationState === 'opening'
+              ? 'translate-x-0 opacity-100'
+              : '-translate-x-3 opacity-0'
+          )}
+        >
+          {/* Fixed controls */}
+          <SidebarHeader />
+          <SearchBar />
+          <GroupControls />
 
-        {/* Virtualized scrollable list */}
-        <WorktreeList />
+          {/* Virtualized scrollable list */}
+          <WorktreeList />
 
-        {/* Fixed bottom toolbar */}
-        <SidebarToolbar />
+          {/* Fixed bottom toolbar */}
+          <SidebarToolbar />
+        </div>
 
         {/* Resize handle */}
-        <div
-          className="absolute top-0 right-0 w-1 h-full cursor-col-resize hover:bg-ring/20 active:bg-ring/30 transition-colors z-10"
-          onMouseDown={onResizeStart}
-        />
+        {renderedOpen ? (
+          <div
+            className="absolute top-0 right-0 w-1 h-full cursor-col-resize hover:bg-ring/20 active:bg-ring/30 transition-colors z-10"
+            onMouseDown={onResizeStart}
+          />
+        ) : null}
       </div>
 
       {/* Dialog (rendered outside sidebar to avoid clipping) */}
diff --git a/src/renderer/src/components/terminal-pane/pane-helpers.ts b/src/renderer/src/components/terminal-pane/pane-helpers.ts
index 5a78c18e42f..f70c0e09120 100644
--- a/src/renderer/src/components/terminal-pane/pane-helpers.ts
+++ b/src/renderer/src/components/terminal-pane/pane-helpers.ts
@@ -1,12 +1,24 @@
 import type { PaneManager } from '@/lib/pane-manager/pane-manager'
+import type { ManagedPane } from '@/lib/pane-manager/pane-manager-types'
+
+function fitAndRefreshPane(pane: ManagedPane): void {
+  try {
+    pane.fitAddon.fit()
+    // Why: width animations from the left/right sidebars can leave xterm's
+    // renderer showing only the pane background until some later paint or PTY
+    // write arrives. Forcing a viewport refresh after fit keeps the existing
+    // scrollback visible throughout the transition instead of flashing blank.
+    if (pane.terminal.rows > 0) {
+      pane.terminal.refresh(0, pane.terminal.rows - 1)
+    }
+  } catch {
+    /* ignore */
+  }
+}
 
 export function fitPanes(manager: PaneManager): void {
   for (const pane of manager.getPanes()) {
-    try {
-      pane.fitAddon.fit()
-    } catch {
-      /* ignore */
-    }
+    fitAndRefreshPane(pane)
   }
 }
 
diff --git a/src/renderer/src/components/terminal-pane/use-terminal-pane-global-effects.ts b/src/renderer/src/components/terminal-pane/use-terminal-pane-global-effects.ts
index f6efa8d638b..5666abb5899 100644
--- a/src/renderer/src/components/terminal-pane/use-terminal-pane-global-effects.ts
+++ b/src/renderer/src/components/terminal-pane/use-terminal-pane-global-effects.ts
@@ -120,6 +120,56 @@ export function useTerminalPaneGlobalEffects({
     // eslint-disable-next-line react-hooks/exhaustive-deps
   }, [isActive])
 
+  useEffect(() => {
+    if (!isActive) {
+      return
+    }
+
+    let restoreTimer: number | null = null
+    const restoreGpuRendering = (): void => {
+      if (restoreTimer !== null) {
+        window.clearTimeout(restoreTimer)
+        restoreTimer = null
+      }
+      const manager = managerRef.current
+      if (!manager) {
+        return
+      }
+      manager.resumeRendering()
+      fitPanes(manager)
+    }
+
+    const onLayoutTransition = (event: Event): void => {
+      const durationMs = Math.max(
+        0,
+        ((event as CustomEvent<{ durationMs?: number }>).detail?.durationMs ?? 0) + 34
+      )
+      const manager = managerRef.current
+      if (!manager) {
+        return
+      }
+      // Why: xterm's WebGL renderer can briefly clear to the pane background
+      // during animated sidebar width changes even though the terminal itself
+      // is still alive. Suspending GPU rendering for just the transition window
+      // keeps the DOM renderer in charge while the layout is unstable, then we
+      // restore WebGL after the animation finishes.
+      manager.suspendRendering()
+      fitPanes(manager)
+      if (restoreTimer !== null) {
+        window.clearTimeout(restoreTimer)
+      }
+      restoreTimer = window.setTimeout(restoreGpuRendering, durationMs)
+    }
+
+    window.addEventListener('orca-layout-transition', onLayoutTransition)
+    return () => {
+      window.removeEventListener('orca-layout-transition', onLayoutTransition)
+      if (restoreTimer !== null) {
+        window.clearTimeout(restoreTimer)
+      }
+    }
+  }, [isActive, managerRef])
+
   useEffect(() => {
     return window.api.ui.onFileDrop(({ path, target }) => {
       if (!isActiveRef.current || target !== 'terminal') {
diff --git a/src/renderer/src/hooks/useSidebarResize.test.ts b/src/renderer/src/hooks/useSidebarResize.test.ts
index 916b941b2a2..6ffb1759292 100644
--- a/src/renderer/src/hooks/useSidebarResize.test.ts
+++ b/src/renderer/src/hooks/useSidebarResize.test.ts
@@ -2,7 +2,9 @@ import { describe, expect, it } from 'vitest'
 import {
   clampSidebarResizeWidth,
   getNextSidebarResizeWidth,
-  getRenderedSidebarWidthCssValue
+  getRenderedSidebarWidthCssValue,
+  getRenderedSidebarWidthPx,
+  interpolateSidebarAnimationWidth
 } from './useSidebarResize'
 
 describe('useSidebarResize helpers', () => {
@@ -63,8 +65,19 @@ describe('useSidebarResize helpers', () => {
   })
 
   it('renders closed sidebars at zero width and open sidebars with extra width', () => {
+    expect(getRenderedSidebarWidthPx(false, 280, 40)).toBe(0)
+    expect(getRenderedSidebarWidthPx(true, 280, 0)).toBe(280)
+    expect(getRenderedSidebarWidthPx(true, 280, 40)).toBe(320)
     expect(getRenderedSidebarWidthCssValue(false, 280, 40)).toBe('0px')
     expect(getRenderedSidebarWidthCssValue(true, 280, 0)).toBe('280px')
     expect(getRenderedSidebarWidthCssValue(true, 280, 40)).toBe('320px')
   })
+
+  it('interpolates sidebar toggle widths with clamped easing progress', () => {
+    expect(interpolateSidebarAnimationWidth(0, 320, -1)).toBe(0)
+    expect(interpolateSidebarAnimationWidth(0, 320, 0)).toBe(0)
+    expect(interpolateSidebarAnimationWidth(0, 320, 1)).toBe(320)
+    expect(interpolateSidebarAnimationWidth(0, 320, 2)).toBe(320)
+    expect(interpolateSidebarAnimationWidth(0, 320, 0.5)).toBe(160)
+  })
 })
diff --git a/src/renderer/src/hooks/useSidebarResize.ts b/src/renderer/src/hooks/useSidebarResize.ts
index 437f444b1c5..a57bb1f74fa 100644
--- a/src/renderer/src/hooks/useSidebarResize.ts
+++ b/src/renderer/src/hooks/useSidebarResize.ts
@@ -1,5 +1,9 @@
 import React, { useCallback, useEffect, useLayoutEffect, useRef, useState } from 'react'
 
+const SIDEBAR_TOGGLE_ANIMATION_MS = 200
+
+export type SidebarContentAnimationState = 'opening' | 'open' | 'closing' | 'closed'
+
 type UseSidebarResizeOptions = {
   isOpen: boolean
   width: number
@@ -14,6 +18,8 @@ type UseSidebarResizeResult<T extends HTMLElement> = {
   containerRef: React.RefObject<T | null>
   isResizing: boolean
   onResizeStart: (event: React.MouseEvent) => void
+  renderedOpen: boolean
+  contentAnimationState: SidebarContentAnimationState
 }
 
 export function clampSidebarResizeWidth(width: number, minWidth: number, maxWidth: number): number {
@@ -25,7 +31,28 @@ export function getRenderedSidebarWidthCssValue(
   width: number,
   renderedExtraWidth: number
 ): string {
-  return isOpen ? `${width + renderedExtraWidth}px` : '0px'
+  return `${getRenderedSidebarWidthPx(isOpen, width, renderedExtraWidth)}px`
+}
+
+export function getRenderedSidebarWidthPx(
+  isOpen: boolean,
+  width: number,
+  renderedExtraWidth: number
+): number {
+  return isOpen ? width + renderedExtraWidth : 0
+}
+
+export function interpolateSidebarAnimationWidth(
+  startWidth: number,
+  endWidth: number,
+  progress: number
+): number {
+  const clampedProgress = Math.min(1, Math.max(0, progress))
+  const easedProgress =
+    clampedProgress < 0.5
+      ? 4 * clampedProgress * clampedProgress * clampedProgress
+      : 1 - Math.pow(-2 * clampedProgress + 2, 3) / 2
+  return startWidth + (endWidth - startWidth) * easedProgress
 }
 
 export function getNextSidebarResizeWidth({
@@ -62,7 +89,13 @@ export function useSidebarResize<T extends HTMLElement>({
   const startWidthRef = useRef(width)
   const draftWidthRef = useRef(width)
   const frameRef = useRef<number | null>(null)
+  const closeTimerRef = useRef<number | null>(null)
+  const openFrameRef = useRef<number | null>(null)
   const [isResizing, setIsResizing] = useState(false)
+  const [renderedOpen, setRenderedOpen] = useState(isOpen)
+  const [contentAnimationState, setContentAnimationState] = useState<SidebarContentAnimationState>(
+    isOpen ? 'open' : 'closed'
+  )
 
   const resetDocumentStyles = useCallback(() => {
     document.body.style.cursor = ''
@@ -70,7 +103,7 @@ export function useSidebarResize<T extends HTMLElement>({
   }, [])
 
   const applyRenderedWidth = useCallback(
-    (nextWidth: number) => {
+    (nextWidth: number, nextIsOpen: boolean = renderedOpen) => {
       const container = containerRef.current
       if (!container) {
         return
@@ -80,9 +113,13 @@ export function useSidebarResize<T extends HTMLElement>({
       // React props. Any unrelated rerender during a drag would otherwise
       // snap the DOM width back to the last persisted store value and make the
       // handle feel like it is lagging behind the pointer.
-      container.style.width = getRenderedSidebarWidthCssValue(isOpen, nextWidth, renderedExtraWidth)
+      container.style.width = getRenderedSidebarWidthCssValue(
+        nextIsOpen,
+        nextWidth,
+        renderedExtraWidth
+      )
     },
-    [isOpen, renderedExtraWidth]
+    [renderedOpen, renderedExtraWidth]
   )
 
   useLayoutEffect(() => {
@@ -94,6 +131,52 @@ export function useSidebarResize<T extends HTMLElement>({
     applyRenderedWidth(width)
   }, [applyRenderedWidth, width])
 
+  useEffect(() => {
+    if (closeTimerRef.current !== null) {
+      window.clearTimeout(closeTimerRef.current)
+      closeTimerRef.current = null
+    }
+    if (openFrameRef.current !== null) {
+      cancelAnimationFrame(openFrameRef.current)
+      openFrameRef.current = null
+    }
+
+    if (isOpen) {
+      setRenderedOpen(true)
+      setContentAnimationState((current) => (current === 'open' ? current : 'opening'))
+      // Why: opening reserves the layout width immediately so the terminal
+      // resizes once, then animates only the sidebar's inner content. This
+      // avoids the terminal blanking seen during continuous shell-width
+      // animation while still giving the sidebar a smooth visual transition.
+      openFrameRef.current = window.requestAnimationFrame(() => {
+        openFrameRef.current = null
+        setContentAnimationState('open')
+      })
+      return
+    }
+
+    setContentAnimationState((current) => (current === 'closed' ? current : 'closing'))
+    // Why: keep the sidebar's layout width alive during the exit animation so
+    // the user sees content slide/fade away first, then release the space at
+    // the end. The terminal only snaps once when the sidebar is fully gone.
+    closeTimerRef.current = window.setTimeout(() => {
+      closeTimerRef.current = null
+      setRenderedOpen(false)
+      setContentAnimationState('closed')
+    }, SIDEBAR_TOGGLE_ANIMATION_MS)
+
+    return () => {
+      if (closeTimerRef.current !== null) {
+        window.clearTimeout(closeTimerRef.current)
+        closeTimerRef.current = null
+      }
+      if (openFrameRef.current !== null) {
+        cancelAnimationFrame(openFrameRef.current)
+        openFrameRef.current = null
+      }
+    }
+  }, [isOpen])
+
   const stopResize = useCallback(() => {
     if (!isResizingRef.current) {
       return
@@ -162,6 +245,14 @@ export function useSidebarResize<T extends HTMLElement>({
         frameRef.current = null
       }
 
+      if (closeTimerRef.current !== null) {
+        window.clearTimeout(closeTimerRef.current)
+        closeTimerRef.current = null
+      }
+      if (openFrameRef.current !== null) {
+        cancelAnimationFrame(openFrameRef.current)
+        openFrameRef.current = null
+      }
       isResizingRef.current = false
       resetDocumentStyles()
     }
@@ -181,5 +272,5 @@ export function useSidebarResize<T extends HTMLElement>({
     [width]
   )
 
-  return { containerRef, isResizing, onResizeStart }
+  return { containerRef, isResizing, onResizeStart, renderedOpen, contentAnimationState }
 }