diff --git a/packages/quill/src/core/emitter.ts b/packages/quill/src/core/emitter.ts
index 7e981ed47b..6076ee7581 100644
--- a/packages/quill/src/core/emitter.ts
+++ b/packages/quill/src/core/emitter.ts
@@ -5,16 +5,30 @@ import logger from './logger.js';
 const debug = logger('quill:events');
 const EVENTS = ['selectionchange', 'mousedown', 'mouseup', 'click'];
 
-EVENTS.forEach((eventName) => {
-  document.addEventListener(eventName, (...args) => {
-    Array.from(document.querySelectorAll('.ql-container')).forEach((node) => {
-      const quill = instances.get(node);
-      if (quill && quill.emitter) {
-        quill.emitter.handleDOM(...args);
-      }
+// Documents where we've already registered Quill's global event listeners.
+// WeakSet so entries are dropped when a document is GC'd (e.g. JSDOM teardown).
+const registeredDocuments = new WeakSet<Document>();
+
+// Registers global event listeners on the given document if not already present.
+// Called lazily from the Quill constructor to avoid touching `document` at import
+// time, which would crash in non-browser environments (Node, SSR).
+function ensureDocumentListeners(doc: Document) {
+  if (registeredDocuments.has(doc)) return;
+  registeredDocuments.add(doc);
+
+  // Queries are scoped to `doc` rather than the global `document` so
+  // listeners stay correct in multi-document scenarios (iframes, JSDOM).
+  EVENTS.forEach((eventName) => {
+    doc.addEventListener(eventName, (...args) => {
+      Array.from(doc.querySelectorAll('.ql-container')).forEach((node) => {
+        const quill = instances.get(node);
+        if (quill && quill.emitter) {
+          quill.emitter.handleDOM(...args);
+        }
+      });
     });
   });
-});
+}
 
 class Emitter extends EventEmitter<string> {
   static events = {
@@ -72,4 +86,5 @@ class Emitter extends EventEmitter<string> {
 export type EmitterSource =
   (typeof Emitter.sources)[keyof typeof Emitter.sources];
 
+export { ensureDocumentListeners };
 export default Emitter;
diff --git a/packages/quill/src/core/quill.ts b/packages/quill/src/core/quill.ts
index 60744570f0..a84c7df48c 100644
--- a/packages/quill/src/core/quill.ts
+++ b/packages/quill/src/core/quill.ts
@@ -10,7 +10,7 @@ import type History from '../modules/history.js';
 import type Keyboard from '../modules/keyboard.js';
 import type Uploader from '../modules/uploader.js';
 import Editor from './editor.js';
-import Emitter from './emitter.js';
+import Emitter, { ensureDocumentListeners } from './emitter.js';
 import type { EmitterSource } from './emitter.js';
 import instances from './instances.js';
 import logger from './logger.js';
@@ -209,6 +209,7 @@ class Quill {
     this.container.classList.add('ql-container');
     this.container.innerHTML = '';
     instances.set(this.container, this);
+    ensureDocumentListeners(this.container.ownerDocument);
     this.root = this.addContainer('ql-editor');
     this.root.classList.add('ql-blank');
     this.emitter = new Emitter();
diff --git a/packages/quill/src/modules/clipboard.ts b/packages/quill/src/modules/clipboard.ts
index 78ea670839..4e6f948626 100644
--- a/packages/quill/src/modules/clipboard.ts
+++ b/packages/quill/src/modules/clipboard.ts
@@ -29,14 +29,21 @@ const debug = logger('quill:clipboard');
 type Selector = string | Node['TEXT_NODE'] | Node['ELEMENT_NODE'];
 type Matcher = (node: Node, delta: Delta, scroll: ScrollBlot) => Delta;
 
+// Constants from the browser's global "Node" object.
+// Strong types ensure the constants are accurate,
+// while avoiding an import time dependency on browser provided global.
+// Avoiding this dependency allows this code to be imported more easily in non-browser environments such as tests and SSR.
+const TEXT_NODE: typeof Node.TEXT_NODE = 3;
+const ELEMENT_NODE: typeof Node.ELEMENT_NODE = 1;
+
 const CLIPBOARD_CONFIG: [Selector, Matcher][] = [
-  [Node.TEXT_NODE, matchText],
-  [Node.TEXT_NODE, matchNewline],
+  [TEXT_NODE, matchText],
+  [TEXT_NODE, matchNewline],
   ['br', matchBreak],
-  [Node.ELEMENT_NODE, matchNewline],
-  [Node.ELEMENT_NODE, matchBlot],
-  [Node.ELEMENT_NODE, matchAttributor],
-  [Node.ELEMENT_NODE, matchStyles],
+  [ELEMENT_NODE, matchNewline],
+  [ELEMENT_NODE, matchBlot],
+  [ELEMENT_NODE, matchAttributor],
+  [ELEMENT_NODE, matchStyles],
   ['li', matchIndent],
   ['ol, ul', matchList],
   ['pre', matchCodeBlock],
diff --git a/packages/quill/src/modules/keyboard.ts b/packages/quill/src/modules/keyboard.ts
index 7941b370f5..2a0ff8a434 100644
--- a/packages/quill/src/modules/keyboard.ts
+++ b/packages/quill/src/modules/keyboard.ts
@@ -10,7 +10,10 @@ import type { Range } from '../core/selection.js';
 
 const debug = logger('quill:keyboard');
 
-const SHORTKEY = /Mac/i.test(navigator.platform) ? 'metaKey' : 'ctrlKey';
+const SHORTKEY =
+  typeof navigator !== 'undefined' && /Mac/i.test(navigator.platform)
+    ? 'metaKey'
+    : 'ctrlKey';
 
 export interface Context {
   collapsed: boolean;
diff --git a/packages/quill/src/modules/syntax.ts b/packages/quill/src/modules/syntax.ts
index da99fdc41d..621877f230 100644
--- a/packages/quill/src/modules/syntax.ts
+++ b/packages/quill/src/modules/syntax.ts
@@ -334,7 +334,7 @@ class Syntax extends Module<SyntaxOptions> {
 }
 Syntax.DEFAULTS = {
   hljs: (() => {
-    return window.hljs;
+    return typeof window !== 'undefined' ? window.hljs : null;
   })(),
   interval: 1000,
   languages: [
diff --git a/packages/quill/src/modules/uiNode.ts b/packages/quill/src/modules/uiNode.ts
index 780713a3ba..3e12cb22e0 100644
--- a/packages/quill/src/modules/uiNode.ts
+++ b/packages/quill/src/modules/uiNode.ts
@@ -2,7 +2,8 @@ import { ParentBlot } from 'parchment';
 import Module from '../core/module.js';
 import Quill from '../core/quill.js';
 
-const isMac = /Mac/i.test(navigator.platform);
+const isMac =
+  typeof navigator !== 'undefined' && /Mac/i.test(navigator.platform);
 
 // Export for testing
 export const TTL_FOR_VALID_SELECTION_CHANGE = 100;