diff --git a/addons/addon-fit/src/FitAddon.ts b/addons/addon-fit/src/FitAddon.ts
index 3d7dc0a0..283af354 100644
--- a/addons/addon-fit/src/FitAddon.ts
+++ b/addons/addon-fit/src/FitAddon.ts
@@ -6,6 +6,7 @@
 import type { Terminal, ITerminalAddon } from '@xterm/xterm';
 import type { FitAddon as IFitApi } from '@xterm/addon-fit';
 import { IRenderDimensions } from 'browser/renderer/shared/Types';
+import { ViewportConstants } from 'browser/shared/Constants';
 
 interface ITerminalDimensions {
   /**
@@ -22,11 +23,6 @@ interface ITerminalDimensions {
 const MINIMUM_COLS = 2;
 const MINIMUM_ROWS = 1;
 
-// Must remain in sync with the value in core's viewport
-const enum Constants {
-  DEFAULT_SCROLL_BAR_WIDTH = 14
-}
-
 export class FitAddon implements ITerminalAddon , IFitApi {
   private _terminal: Terminal | undefined;
 
@@ -71,7 +67,7 @@ export class FitAddon implements ITerminalAddon , IFitApi {
 
     const scrollbarWidth = (this._terminal.options.scrollback === 0
       ? 0
-      : (this._terminal.options.overviewRulerWidth || Constants.DEFAULT_SCROLL_BAR_WIDTH));
+      : (this._terminal.options.overviewRulerWidth || ViewportConstants.DEFAULT_SCROLL_BAR_WIDTH));
 
     const parentElementStyle = window.getComputedStyle(this._terminal.element.parentElement);
     const parentElementHeight = parseInt(parentElementStyle.getPropertyValue('height'));
diff --git a/src/browser/Viewport.ts b/src/browser/Viewport.ts
index f1c031e4..423a85bb 100644
--- a/src/browser/Viewport.ts
+++ b/src/browser/Viewport.ts
@@ -4,6 +4,7 @@
  */
 
 import { ICoreBrowserService, IRenderService, IThemeService } from 'browser/services/Services';
+import { ViewportConstants } from 'browser/shared/Constants';
 import { EventEmitter, runAndSubscribe } from 'common/EventEmitter';
 import { Disposable, toDisposable } from 'common/Lifecycle';
 import { IBufferService, IOptionsService } from 'common/services/Services';
@@ -12,10 +13,6 @@ import { SmoothScrollableElement } from 'vs/base/browser/ui/scrollbar/scrollable
 import type { ScrollableElementChangeOptions } from 'vs/base/browser/ui/scrollbar/scrollableElementOptions';
 import { Scrollable, ScrollbarVisibility, type ScrollEvent } from 'vs/base/common/scrollable';
 
-const enum Constants {
-  DEFAULT_SCROLL_BAR_WIDTH = 14
-}
-
 export class Viewport extends Disposable {
 
   protected _onRequestScrollLines = this.register(new EventEmitter<number>());
@@ -118,7 +115,7 @@ export class Viewport extends Disposable {
     return {
       mouseWheelScrollSensitivity: this._optionsService.rawOptions.scrollSensitivity,
       fastScrollSensitivity: this._optionsService.rawOptions.fastScrollSensitivity,
-      verticalScrollbarSize: this._optionsService.rawOptions.overviewRulerWidth || Constants.DEFAULT_SCROLL_BAR_WIDTH
+      verticalScrollbarSize: this._optionsService.rawOptions.overviewRulerWidth || ViewportConstants.DEFAULT_SCROLL_BAR_WIDTH
     };
   }
 
diff --git a/src/browser/shared/Constants.ts b/src/browser/shared/Constants.ts
new file mode 100644
index 00000000..58b7d2f7
--- /dev/null
+++ b/src/browser/shared/Constants.ts
@@ -0,0 +1,8 @@
+/**
+ * Copyright (c) 2024 The xterm.js authors. All rights reserved.
+ * @license MIT
+ */
+
+export const enum ViewportConstants {
+  DEFAULT_SCROLL_BAR_WIDTH = 14
+}