diff --git a/specifyweb/frontend/js_src/lib/components/Atoms/index.tsx b/specifyweb/frontend/js_src/lib/components/Atoms/index.tsx
index c053ec0655c..805ddb91797 100644
--- a/specifyweb/frontend/js_src/lib/components/Atoms/index.tsx
+++ b/specifyweb/frontend/js_src/lib/components/Atoms/index.tsx
@@ -94,6 +94,8 @@ export const Key = wrap(
   'bg-gray-200 border-1 dark:border-none dark:bg-neutral-700 rounded-sm mx-1 p-0.5'
 );
 
+const defaultOneRem = 16;
 export const oneRem = Number.parseFloat(
-  getComputedStyle(document.documentElement).fontSize
+  globalThis.getComputedStyle?.(document.documentElement).fontSize ??
+    defaultOneRem
 );
diff --git a/specifyweb/frontend/js_src/lib/components/Core/Entrypoint.tsx b/specifyweb/frontend/js_src/lib/components/Core/Entrypoint.tsx
index fcf1b7fd7ca..575b5eba5e3 100644
--- a/specifyweb/frontend/js_src/lib/components/Core/Entrypoint.tsx
+++ b/specifyweb/frontend/js_src/lib/components/Core/Entrypoint.tsx
@@ -30,7 +30,7 @@ function entrypoint(): void {
   console.log(entrypointName);
   unlockInitialContext(entrypointName);
 
-  globalThis.window.addEventListener('load', () => {
+  globalThis.addEventListener?.('load', () => {
     const root = document.getElementById('root');
     const portalRoot = document.getElementById('portal-root');
     if (root === null || portalRoot === null)
diff --git a/specifyweb/frontend/js_src/lib/components/Core/OnlineStatus.tsx b/specifyweb/frontend/js_src/lib/components/Core/OnlineStatus.tsx
index 666fa6df1a5..274232eb9ee 100644
--- a/specifyweb/frontend/js_src/lib/components/Core/OnlineStatus.tsx
+++ b/specifyweb/frontend/js_src/lib/components/Core/OnlineStatus.tsx
@@ -22,12 +22,12 @@ export function OnlineStatus(): JSX.Element | null {
       setShowOnlineStatus(false);
     }
 
-    window.addEventListener('online', handleOnline);
-    window.addEventListener('offline', handleOffline);
+    globalThis.addEventListener('online', handleOnline);
+    globalThis.addEventListener('offline', handleOffline);
 
     return () => {
-      window.removeEventListener('online', handleOnline);
-      window.removeEventListener('offline', handleOffline);
+      globalThis.removeEventListener('online', handleOnline);
+      globalThis.removeEventListener('offline', handleOffline);
     };
   }, []);
 
diff --git a/specifyweb/frontend/js_src/lib/components/Molecules/Dialog.tsx b/specifyweb/frontend/js_src/lib/components/Molecules/Dialog.tsx
index 724b87fe657..cf3ea52c8cb 100644
--- a/specifyweb/frontend/js_src/lib/components/Molecules/Dialog.tsx
+++ b/specifyweb/frontend/js_src/lib/components/Molecules/Dialog.tsx
@@ -76,12 +76,13 @@ const dialogIndexes = new Set<number>();
 const getNextIndex = (): number =>
   dialogIndexes.size === 0 ? initialIndex : Math.max(...dialogIndexes) + 1;
 
-const supportsBackdropBlur = globalThis.CSS.supports(
-  '((-webkit-backdrop-filter: none) or (backdrop-filter: none))'
-);
+const supportsBackdropBlur =
+  globalThis.CSS?.supports(
+    '((-webkit-backdrop-filter: none) or (backdrop-filter: none))'
+  ) ?? false;
 
 // Used for 'inert' attribute addition
-const root = document.getElementById('root');
+const root = globalThis.document?.getElementById('root');
 
 /**
  * Modal or non-modal dialog. Highly customizable. Used all over the place
diff --git a/specifyweb/frontend/js_src/lib/components/Molecules/GeoLocate.tsx b/specifyweb/frontend/js_src/lib/components/Molecules/GeoLocate.tsx
index f2f83dd0dd2..53040fd33d1 100644
--- a/specifyweb/frontend/js_src/lib/components/Molecules/GeoLocate.tsx
+++ b/specifyweb/frontend/js_src/lib/components/Molecules/GeoLocate.tsx
@@ -45,7 +45,7 @@ export function GenericGeoLocate({
       handleUpdate?.({ latitude, longitude, uncertainty, polygon });
     }
 
-    globalThis.window.addEventListener('message', listener);
+    globalThis.addEventListener('message', listener);
     return (): void => globalThis.removeEventListener('message', listener);
   }, [handleUpdate]);
 
diff --git a/specifyweb/frontend/js_src/lib/components/Molecules/Tooltips.tsx b/specifyweb/frontend/js_src/lib/components/Molecules/Tooltips.tsx
index 7a3f8173e9f..205abeca782 100644
--- a/specifyweb/frontend/js_src/lib/components/Molecules/Tooltips.tsx
+++ b/specifyweb/frontend/js_src/lib/components/Molecules/Tooltips.tsx
@@ -219,7 +219,7 @@ let delayFocusIn = 400;
 /** Delay before showing tooltip if using mouse */
 let delayMouseIn = 1000;
 // Disable delays on touch screen devices
-window?.addEventListener(
+globalThis.addEventListener?.(
   'touchstart',
   () => {
     delayFocusIn = 0;
diff --git a/specifyweb/frontend/js_src/lib/components/WorkBench/WbView.tsx b/specifyweb/frontend/js_src/lib/components/WorkBench/WbView.tsx
index 64ee45dab9b..5ea8aaaef1d 100644
--- a/specifyweb/frontend/js_src/lib/components/WorkBench/WbView.tsx
+++ b/specifyweb/frontend/js_src/lib/components/WorkBench/WbView.tsx
@@ -300,7 +300,7 @@ export class WbView extends Backbone.View {
       this.wbUtils.toggleCellTypes('invalidCells', 'remove');
 
     this.cells.flushIndexedCellData = true;
-    globalThis.window.addEventListener('resize', this.handleResize);
+    globalThis.addEventListener('resize', this.handleResize);
 
     return this;
   }
diff --git a/specifyweb/frontend/js_src/lib/utils/cache/index.ts b/specifyweb/frontend/js_src/lib/utils/cache/index.ts
index 08ee8123751..f1a0d685c81 100644
--- a/specifyweb/frontend/js_src/lib/utils/cache/index.ts
+++ b/specifyweb/frontend/js_src/lib/utils/cache/index.ts
@@ -51,7 +51,7 @@ let eventListenerIsInitialized = false;
 
 /** Listen for changes to localStorage from other tabs */
 function initialize(): void {
-  globalThis.addEventListener(
+  globalThis.addEventListener?.(
     'storage',
     ({ storageArea, key: formattedKey, newValue }) => {
       // "key" is null only when running `localStorage.clear()`