diff --git a/workspaces/leetcode-zen-mode/src/extension/content-script-isolated/main.ts b/workspaces/leetcode-zen-mode/src/extension/content-script-isolated/main.ts
index 5d952183..3d6c7b00 100644
--- a/workspaces/leetcode-zen-mode/src/extension/content-script-isolated/main.ts
+++ b/workspaces/leetcode-zen-mode/src/extension/content-script-isolated/main.ts
@@ -1,6 +1,8 @@
 import { getChrome } from "@code-chronicles/util/browser-extensions/chrome/getChrome";
 
-import { SETTINGS_ATTRIBUTE, SETTINGS_STORAGE_KEY } from "../constants.ts";
+import { PUBLIC_SETTINGS_STORAGE_KEY } from "../shared/public-settings/constants.ts";
+import { publicSettingsZodType } from "../shared/public-settings/publicSettingsZodType.ts";
+import { writePublicSettingsToDocumentAttribute } from "../shared/public-settings/writePublicSettingsToDocumentAttribute.ts";
 
 /**
  * Entry point for the extension content script that will run in an isolated
@@ -18,10 +20,15 @@ async function main(): Promise<void> {
     return;
   }
 
-  const settings = await chrome.storage.sync.get(SETTINGS_STORAGE_KEY);
-  document.documentElement.setAttribute(
-    SETTINGS_ATTRIBUTE,
-    JSON.stringify(settings[SETTINGS_STORAGE_KEY]),
+  const unsafePublicSettings: unknown = (
+    await chrome.storage.sync.get(PUBLIC_SETTINGS_STORAGE_KEY)
+  )[PUBLIC_SETTINGS_STORAGE_KEY];
+  if (unsafePublicSettings == null) {
+    return;
+  }
+
+  writePublicSettingsToDocumentAttribute(
+    publicSettingsZodType.parse(unsafePublicSettings),
   );
 }
 
diff --git a/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/isArrayOfDataByDifficulty.ts b/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/isArrayOfDataByDifficulty.ts
index 533e9f6e..e8a143ca 100644
--- a/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/isArrayOfDataByDifficulty.ts
+++ b/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/isArrayOfDataByDifficulty.ts
@@ -1,10 +1,13 @@
 import { isNonArrayObject } from "@code-chronicles/util/isNonArrayObject";
-import { isString } from "@code-chronicles/util/isString";
+
+import { difficultyZodType, type Difficulty } from "../problemDifficulties.ts";
 
 export function isArrayOfDataByDifficulty(
   arr: unknown[],
-): arr is ({ difficulty: string } & Record<string, unknown>)[] {
+): arr is ({ difficulty: Difficulty } & Record<string, unknown>)[] {
   return arr.every(
-    (elem) => isNonArrayObject(elem) && isString(elem.difficulty),
+    (elem) =>
+      isNonArrayObject(elem) &&
+      difficultyZodType.safeParse(elem.difficulty).success,
   );
 }
diff --git a/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/patchJsxFactory.ts b/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/patchJsxFactory.ts
index e18361b1..87942786 100644
--- a/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/patchJsxFactory.ts
+++ b/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/patchJsxFactory.ts
@@ -3,6 +3,8 @@ import { isString } from "@code-chronicles/util/isString";
 import { assignFunctionCosmeticProperties } from "@code-chronicles/util/object-properties/assignFunctionCosmeticProperties";
 import { NullReactElement } from "@code-chronicles/util/browser-extensions/NullReactElement";
 
+import { difficultyZodType } from "../problemDifficulties.ts";
+
 type CreateElementFn = (
   this: unknown,
   elementType: unknown,
@@ -23,7 +25,7 @@ export function patchJsxFactory<T extends CreateElementFn>(
           Array.isArray(props.items) &&
           props.items.some(
             (it: Record<string, unknown>) =>
-              isString(it.value) && /^easy$/i.test(it.value),
+              difficultyZodType.safeParse(it.value).success,
           )
         ) {
           return createElementFn.apply(this, [NullReactElement, {}]);
@@ -35,6 +37,7 @@ export function patchJsxFactory<T extends CreateElementFn>(
         if (
           isNonArrayObject(props) &&
           isString(props.category) &&
+          // TODO: use the preferred difficulty
           /^(?:medium|hard)$/i.test(props.category)
         ) {
           return createElementFn.apply(this, [NullReactElement, {}]);
diff --git a/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/rewriteLeetCodeAggregateDataForDifficulty.ts b/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/rewriteLeetCodeAggregateDataForDifficulty.ts
index 61c898c2..0f72d28d 100644
--- a/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/rewriteLeetCodeAggregateDataForDifficulty.ts
+++ b/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/rewriteLeetCodeAggregateDataForDifficulty.ts
@@ -10,6 +10,7 @@ import { stringToCase, type Case } from "@code-chronicles/util/stringToCase";
 
 import { isArrayOfDataByDifficulty } from "./isArrayOfDataByDifficulty.ts";
 import { PREFERRED_STRING_CASE, STRING_CASE_CHECKERS } from "./stringCase.ts";
+import type { Difficulty } from "../problemDifficulties.ts";
 
 /**
  * Some of the LeetCode GraphQL data is aggregate statistics about problems
@@ -18,6 +19,7 @@ import { PREFERRED_STRING_CASE, STRING_CASE_CHECKERS } from "./stringCase.ts";
  */
 export function rewriteLeetCodeAggregateDataForDifficulty(
   arr: unknown[],
+  uncasedPreferredDifficulty: Difficulty,
 ): unknown[] {
   // Do nothing if it's not the kind of data we're looking for.
   if (!isArrayOfDataByDifficulty(arr)) {
@@ -38,27 +40,33 @@ export function rewriteLeetCodeAggregateDataForDifficulty(
 
   // Prepare some difficulty strings that will come in handy below.
   const allDifficulty = stringToCase("all", difficultyStringCase);
-  const easyDifficulty = stringToCase("easy", difficultyStringCase);
+  const casedPreferredDifficulty = stringToCase(
+    uncasedPreferredDifficulty,
+    difficultyStringCase,
+  );
 
   const elementsByDifficulty = groupBy(arr, (elem) =>
     stringToCase(elem.difficulty, difficultyStringCase),
   );
 
-  // If we have a single "All" item and items with difficulties besides
-  // "All" and "Easy", we will get rid of the extra items, and instead use
-  // a single "Easy" item that's a copy of the "All" item with an updated
-  // difficulty.
+  // If we have a single "All" item and items with difficulties besides "All"
+  // and the preferred difficulty, we will get rid of the extra items, and
+  // instead use a single item that's a copy of the "All" item with an updated
+  // difficulty to be the preferred one.
   if (
     elementsByDifficulty.get(allDifficulty)?.length === 1 &&
     [...elementsByDifficulty.keys()].some(
       (difficulty) =>
-        difficulty !== allDifficulty && difficulty !== easyDifficulty,
+        difficulty !== allDifficulty && difficulty !== casedPreferredDifficulty,
     )
   ) {
     const allElement = only(
       nullthrows(elementsByDifficulty.get(allDifficulty)),
     );
-    return [allElement, { ...allElement, difficulty: easyDifficulty }];
+    return [
+      allElement,
+      { ...allElement, difficulty: casedPreferredDifficulty },
+    ];
   }
 
   // Another option is that we don't have an "All" item. In this case we
@@ -71,18 +79,19 @@ export function rewriteLeetCodeAggregateDataForDifficulty(
   if (
     [...elementsByDifficulty.values()].every((group) => group.length === 1) &&
     [...elementsByDifficulty.keys()].some(
-      (difficulty) => difficulty !== easyDifficulty,
+      (difficulty) => difficulty !== casedPreferredDifficulty,
     )
   ) {
     return [
       mergeObjects(arr, (values, key) => {
         if (key === "difficulty") {
-          return easyDifficulty;
+          return casedPreferredDifficulty;
         }
 
         if (isArrayOfNumbers(values)) {
           const total = sum(values);
 
+          // TODO: weighted average
           if (key === "percentage") {
             return total / (values.length || 1);
           }
diff --git a/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/rewriteLeetCodeGraphQLData.ts b/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/rewriteLeetCodeGraphQLData.ts
index 66b4e80e..a02e3376 100644
--- a/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/rewriteLeetCodeGraphQLData.ts
+++ b/workspaces/leetcode-zen-mode/src/extension/content-script-non-isolated/rewriteLeetCodeGraphQLData.ts
@@ -3,25 +3,16 @@ import { isString } from "@code-chronicles/util/isString";
 import { mapObjectValues } from "@code-chronicles/util/mapObjectValues";
 import { stringToCase } from "@code-chronicles/util/stringToCase";
 
-import { SETTINGS_ATTRIBUTE } from "../constants.ts";
 import { rewriteLeetCodeAggregateDataForDifficulty } from "./rewriteLeetCodeAggregateDataForDifficulty.ts";
 import { PREFERRED_STRING_CASE, STRING_CASE_CHECKERS } from "./stringCase.ts";
-import type { Difficulty } from "../usePreferredDifficulty.ts";
-
-let preferredDifficulty: Difficulty | null = null;
-function getPreferredDifficulty(prevJsonParse: typeof JSON.parse): Difficulty {
-  if (preferredDifficulty == null) {
-    try {
-      preferredDifficulty = (prevJsonParse(
-        String(document.documentElement.getAttribute(SETTINGS_ATTRIBUTE)),
-      ) ?? "Easy") as Difficulty;
-    } catch (err) {
-      console.error(err);
-      preferredDifficulty = "Easy";
-    }
-  }
-
-  return preferredDifficulty;
+import { difficultyZodType } from "../problemDifficulties.ts";
+import type { PublicSettings } from "../shared/public-settings/publicSettingsZodType.ts";
+import { readPublicSettingsFromDocumentAttribute } from "../shared/public-settings/readPublicSettingsFromDocumentAttribute.ts";
+
+let publicSettings: PublicSettings | null = null;
+function getPublicSettings(prevJsonParse: typeof JSON.parse): PublicSettings {
+  return (publicSettings ??=
+    readPublicSettingsFromDocumentAttribute(prevJsonParse));
 }
 
 export function rewriteLeetCodeGraphQLData(
@@ -29,8 +20,13 @@ export function rewriteLeetCodeGraphQLData(
   prevJsonParse: typeof JSON.parse,
 ): unknown {
   if (Array.isArray(value)) {
+    const { preferredDifficulty } = getPublicSettings(prevJsonParse);
+
     // Arrays get some extra processing.
-    const rewrittenValue = rewriteLeetCodeAggregateDataForDifficulty(value);
+    const rewrittenValue = rewriteLeetCodeAggregateDataForDifficulty(
+      value,
+      preferredDifficulty,
+    );
 
     // Recursively process array values.
     return rewrittenValue.map((value) =>
@@ -46,11 +42,12 @@ export function rewriteLeetCodeGraphQLData(
   }
 
   // Rewrite difficulty strings!
-  if (isString(value) && /^(?:easy|medium|hard)$/i.test(value)) {
+  if (isString(value) && difficultyZodType.safeParse(value).success) {
     const stringCase =
       STRING_CASE_CHECKERS.find(([, checker]) => checker(value))?.[0] ??
       PREFERRED_STRING_CASE;
-    return stringToCase(getPreferredDifficulty(prevJsonParse), stringCase);
+    const { preferredDifficulty } = getPublicSettings(prevJsonParse);
+    return stringToCase(preferredDifficulty, stringCase);
   }
 
   // Pass everything else through unchanged.
diff --git a/workspaces/leetcode-zen-mode/src/extension/options-ui/components/App.tsx b/workspaces/leetcode-zen-mode/src/extension/options-ui/components/App.tsx
index 864732cb..a5a5d7b2 100644
--- a/workspaces/leetcode-zen-mode/src/extension/options-ui/components/App.tsx
+++ b/workspaces/leetcode-zen-mode/src/extension/options-ui/components/App.tsx
@@ -1,10 +1,7 @@
 import React from "react";
 
-import {
-  usePreferredDifficulty,
-  DIFFICULTIES,
-  type Difficulty,
-} from "../../usePreferredDifficulty.ts";
+import { usePreferredDifficulty } from "../../usePreferredDifficulty.ts";
+import { DIFFICULTIES, difficultyZodType } from "../../problemDifficulties.ts";
 
 function Options() {
   const [preferredDifficulty, setPreferredDifficulty] =
@@ -17,7 +14,7 @@ function Options() {
         <select
           value={preferredDifficulty}
           onChange={(ev) =>
-            setPreferredDifficulty(ev.target.value as Difficulty)
+            setPreferredDifficulty(difficultyZodType.parse(ev.target.value))
           }
         >
           {DIFFICULTIES.map((difficultyOption) => (
diff --git a/workspaces/leetcode-zen-mode/src/extension/problemDifficulties.ts b/workspaces/leetcode-zen-mode/src/extension/problemDifficulties.ts
new file mode 100644
index 00000000..c712be6c
--- /dev/null
+++ b/workspaces/leetcode-zen-mode/src/extension/problemDifficulties.ts
@@ -0,0 +1,12 @@
+import nullthrows from "nullthrows";
+import { z } from "zod";
+
+export const DIFFICULTIES = ["Easy", "Medium", "Hard"] as const;
+
+export const difficultyZodType = z
+  .string()
+  .transform((s) =>
+    nullthrows(DIFFICULTIES.find((d) => d.toLowerCase() === s.toLowerCase())),
+  );
+
+export type Difficulty = z.infer<typeof difficultyZodType>;
diff --git a/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/constants.ts b/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/constants.ts
new file mode 100644
index 00000000..80fa0756
--- /dev/null
+++ b/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/constants.ts
@@ -0,0 +1,4 @@
+export const PUBLIC_SETTINGS_ATTRIBUTE =
+  "data-leetcode-zen-mode-public-settings";
+
+export const PUBLIC_SETTINGS_STORAGE_KEY = "public-settings";
diff --git a/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/getDefaultPublicSettings.ts b/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/getDefaultPublicSettings.ts
new file mode 100644
index 00000000..f11061ac
--- /dev/null
+++ b/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/getDefaultPublicSettings.ts
@@ -0,0 +1,7 @@
+import type { PublicSettings } from "./publicSettingsZodType.ts";
+
+export function getDefaultPublicSettings(): PublicSettings {
+  return {
+    preferredDifficulty: "Easy",
+  };
+}
diff --git a/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/publicSettingsZodType.ts b/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/publicSettingsZodType.ts
new file mode 100644
index 00000000..95768d00
--- /dev/null
+++ b/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/publicSettingsZodType.ts
@@ -0,0 +1,9 @@
+import { z } from "zod";
+
+import { difficultyZodType } from "../../problemDifficulties.ts";
+
+export const publicSettingsZodType = z.object({
+  preferredDifficulty: difficultyZodType,
+});
+
+export type PublicSettings = z.infer<typeof publicSettingsZodType>;
diff --git a/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/readPublicSettingsFromDocumentAttribute.ts b/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/readPublicSettingsFromDocumentAttribute.ts
new file mode 100644
index 00000000..93ff7eb6
--- /dev/null
+++ b/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/readPublicSettingsFromDocumentAttribute.ts
@@ -0,0 +1,23 @@
+import { PUBLIC_SETTINGS_ATTRIBUTE } from "./constants.ts";
+import { getDefaultPublicSettings } from "./getDefaultPublicSettings.ts";
+import {
+  publicSettingsZodType,
+  type PublicSettings,
+} from "./publicSettingsZodType.ts";
+
+export function readPublicSettingsFromDocumentAttribute(
+  parseFn: typeof JSON.parse = JSON.parse,
+): PublicSettings {
+  try {
+    const attribute = document.documentElement.getAttribute(
+      PUBLIC_SETTINGS_ATTRIBUTE,
+    );
+    if (attribute != null) {
+      return publicSettingsZodType.parse(parseFn(attribute));
+    }
+  } catch (err) {
+    console.error(err);
+  }
+
+  return getDefaultPublicSettings();
+}
diff --git a/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/writePublicSettingsToDocumentAttribute.ts b/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/writePublicSettingsToDocumentAttribute.ts
new file mode 100644
index 00000000..04331644
--- /dev/null
+++ b/workspaces/leetcode-zen-mode/src/extension/shared/public-settings/writePublicSettingsToDocumentAttribute.ts
@@ -0,0 +1,11 @@
+import { PUBLIC_SETTINGS_ATTRIBUTE } from "./constants.ts";
+import type { PublicSettings } from "./publicSettingsZodType.ts";
+
+export function writePublicSettingsToDocumentAttribute(
+  settings: PublicSettings,
+): void {
+  document.documentElement.setAttribute(
+    PUBLIC_SETTINGS_ATTRIBUTE,
+    JSON.stringify(settings),
+  );
+}
diff --git a/workspaces/leetcode-zen-mode/src/extension/useChromeStorage.ts b/workspaces/leetcode-zen-mode/src/extension/useChromeStorage.ts
index 5999f534..9dff4fb9 100644
--- a/workspaces/leetcode-zen-mode/src/extension/useChromeStorage.ts
+++ b/workspaces/leetcode-zen-mode/src/extension/useChromeStorage.ts
@@ -6,7 +6,7 @@ import { getUniqueId } from "@code-chronicles/util/getUniqueId";
 
 let storage: Record<string, unknown> | null = null;
 
-async function writeChanges(): Promise<void> {
+async function readLatestStorageAndNotify(): Promise<void> {
   const chrome = getChrome();
   if (!chrome) {
     return;
@@ -20,13 +20,15 @@ let promise: Promise<void> | null = null;
 
 function getSnapshot(): Record<string, unknown> {
   if (!storage) {
-    throw (promise ??= writeChanges().finally(() => {
+    throw (promise ??= readLatestStorageAndNotify().finally(() => {
       promise = null;
 
       // We never clear the listener but that seems ok.
       getChrome()?.storage.sync.onChanged.addListener((changes) => {
         if (!storage) {
-          writeChanges();
+          // We weren't able to read the storage for some reason... let's try
+          // again?
+          readLatestStorageAndNotify();
           return;
         }
 
@@ -49,6 +51,7 @@ function getSnapshot(): Record<string, unknown> {
   return storage;
 }
 
+// TODO: use a proper event emitter
 const subscribers = new Map<string, () => void>();
 
 function subscribe(sub: () => void): () => void {
@@ -63,6 +66,7 @@ function notifySubscribers(): void {
   }
 }
 
+// TODO: move this hook to the util package
 export function useChromeStorage(): Record<string, unknown> {
   return useSyncExternalStore(subscribe, getSnapshot, () => ({}));
 }
diff --git a/workspaces/leetcode-zen-mode/src/extension/usePreferredDifficulty.ts b/workspaces/leetcode-zen-mode/src/extension/usePreferredDifficulty.ts
index 726a8c7d..02cf13dc 100644
--- a/workspaces/leetcode-zen-mode/src/extension/usePreferredDifficulty.ts
+++ b/workspaces/leetcode-zen-mode/src/extension/usePreferredDifficulty.ts
@@ -1,21 +1,20 @@
-import { z } from "zod";
-
 import { getChrome } from "@code-chronicles/util/browser-extensions/chrome/getChrome";
 
 import { useChromeStorage } from "./useChromeStorage.ts";
-import { SETTINGS_STORAGE_KEY } from "./constants.ts";
-
-export const DIFFICULTIES = ["Easy", "Medium", "Hard"] as const;
-
-const difficultyZodType = z.enum(DIFFICULTIES);
+import { PUBLIC_SETTINGS_STORAGE_KEY } from "./shared/public-settings/constants.ts";
+import {
+  DIFFICULTIES,
+  difficultyZodType,
+  type Difficulty,
+} from "./problemDifficulties.ts";
 
-export type Difficulty = z.infer<typeof difficultyZodType>;
+// TODO: set the whole public settings
 
 async function setPreferredDifficulty(
   newPreferredDifficulty: Difficulty,
 ): Promise<void> {
   await getChrome()?.storage.sync.set({
-    [SETTINGS_STORAGE_KEY]: newPreferredDifficulty,
+    [PUBLIC_SETTINGS_STORAGE_KEY]: newPreferredDifficulty,
   });
 }
 
@@ -26,7 +25,7 @@ export function usePreferredDifficulty(): [
   const storage = useChromeStorage();
 
   const parseResult = difficultyZodType.safeParse(
-    storage[SETTINGS_STORAGE_KEY],
+    storage[PUBLIC_SETTINGS_STORAGE_KEY],
   );
   const preferredDifficulty: Difficulty = parseResult.success
     ? parseResult.data