diff --git a/docs/Tabs.md b/docs/Tabs.md
index 0d6cbfb..f55b9f7 100644
--- a/docs/Tabs.md
+++ b/docs/Tabs.md
@@ -2,6 +2,10 @@
 
 ## Overview
 
+
+
+
+
 The `Tabs` component replaces the inline tab navigation in `ApiDetailPage` with a reusable, fully accessible tab strip featuring a **smooth sliding ink-bar indicator** that animates between tabs using CSS `transition` driven by DOM geometry measurements. No animation libraries required.
 
 ---
diff --git a/src/ThemeContext.tsx b/src/ThemeContext.tsx
index 19c87a1..d1982e7 100644
--- a/src/ThemeContext.tsx
+++ b/src/ThemeContext.tsx
@@ -1,7 +1,6 @@
 import React, { createContext, useContext, useEffect, useState } from 'react';
 import './styles/theme-transition.css';
-
-type Theme = 'light' | 'dark' | 'system';
+import { getPref, setPref, type Theme } from './utils/userPrefs';
 
 interface ThemeContextType {
   theme: Theme;
@@ -13,8 +12,7 @@ const ThemeContext = createContext<ThemeContextType | undefined>(undefined);
 
 export function ThemeProvider({ children }: { children: React.ReactNode }) {
   const [theme, setTheme] = useState<Theme>(() => {
-    const saved = localStorage.getItem('callora-theme');
-    return (saved as Theme) || 'dark';
+    return getPref('theme');
   });
 
   const [actualTheme, setActualTheme] = useState<'light' | 'dark'>(() => {
@@ -34,7 +32,7 @@ export function ThemeProvider({ children }: { children: React.ReactNode }) {
   }, []);
 
   useEffect(() => {
-    localStorage.setItem('callora-theme', theme);
+    setPref('theme', theme);
     
     const root = window.document.documentElement;
     
diff --git a/src/data/mockApis.ts b/src/data/mockApis.ts
index 959fc30..49a5330 100644
--- a/src/data/mockApis.ts
+++ b/src/data/mockApis.ts
@@ -7,6 +7,8 @@ export type Review = {
   verified: boolean;
 };
 
+
+
 export type APIItem = {
   id: string;
   name: string;
diff --git a/src/utils/density.ts b/src/utils/density.ts
index bde3426..fb675b5 100644
--- a/src/utils/density.ts
+++ b/src/utils/density.ts
@@ -1,27 +1,11 @@
-export type DensityPreference = "comfortable" | "compact";
+import { getPref, setPref, type DensityPreference } from './userPrefs';
 
-export const DENSITY_STORAGE_KEY = "callora.density";
-
-const DEFAULT_DENSITY: DensityPreference = "comfortable";
-const VALID_DENSITIES: DensityPreference[] = ["comfortable", "compact"];
+export { type DensityPreference };
 
 export function readDensityPreference(): DensityPreference {
-  if (typeof window === "undefined") {
-    return DEFAULT_DENSITY;
-  }
-
-  const storedValue = window.localStorage.getItem(DENSITY_STORAGE_KEY);
-  if (storedValue && VALID_DENSITIES.includes(storedValue as DensityPreference)) {
-    return storedValue as DensityPreference;
-  }
-
-  return DEFAULT_DENSITY;
+  return getPref('density');
 }
 
 export function persistDensityPreference(density: DensityPreference): void {
-  if (typeof window === "undefined") {
-    return;
-  }
-
-  window.localStorage.setItem(DENSITY_STORAGE_KEY, density);
+  setPref('density', density);
 }
diff --git a/src/utils/userPrefs.test.ts b/src/utils/userPrefs.test.ts
new file mode 100644
index 0000000..623ad4c
--- /dev/null
+++ b/src/utils/userPrefs.test.ts
@@ -0,0 +1,69 @@
+import { describe, it, expect, beforeEach, afterEach, vi } from 'vitest';
+import { getPref, setPref, readAllPrefs, PREFS_STORAGE_KEY, DEFAULT_PREFS } from './userPrefs';
+
+describe('userPrefs', () => {
+  beforeEach(() => {
+    window.localStorage.clear();
+    vi.restoreAllMocks();
+  });
+
+  afterEach(() => {
+    window.localStorage.clear();
+  });
+
+  it('returns default preferences when no data in localStorage', () => {
+    const prefs = readAllPrefs();
+    expect(prefs).toEqual(DEFAULT_PREFS);
+  });
+
+  it('migrates legacy theme key on first load', () => {
+    window.localStorage.setItem('callora-theme', 'light');
+    const prefs = readAllPrefs();
+    
+    expect(prefs.theme).toBe('light');
+    expect(window.localStorage.getItem('callora-theme')).toBeNull(); // Should be removed
+    
+    const savedNewPrefs = JSON.parse(window.localStorage.getItem(PREFS_STORAGE_KEY) || '{}');
+    expect(savedNewPrefs.theme).toBe('light');
+  });
+
+  it('migrates legacy density key on first load', () => {
+    window.localStorage.setItem('callora.density', 'compact');
+    const prefs = readAllPrefs();
+    
+    expect(prefs.density).toBe('compact');
+    expect(window.localStorage.getItem('callora.density')).toBeNull(); // Should be removed
+  });
+
+  it('ignores invalid legacy values during migration', () => {
+    window.localStorage.setItem('callora-theme', 'invalid-theme');
+    window.localStorage.setItem('callora.density', 'invalid-density');
+    
+    const prefs = readAllPrefs();
+    expect(prefs.theme).toBe('dark'); // Fallback to default
+    expect(prefs.density).toBe('comfortable'); // Fallback to default
+  });
+
+  it('handles JSON parse failures gracefully', () => {
+    window.localStorage.setItem(PREFS_STORAGE_KEY, '{invalid json');
+    const prefs = readAllPrefs();
+    
+    expect(prefs).toEqual(DEFAULT_PREFS); // Should recover and return defaults
+  });
+
+  it('merges stored prefs with defaults if fields are missing', () => {
+    window.localStorage.setItem(PREFS_STORAGE_KEY, JSON.stringify({ theme: 'light' }));
+    const prefs = readAllPrefs();
+    
+    expect(prefs.theme).toBe('light');
+    expect(prefs.density).toBe('comfortable'); // From defaults
+  });
+
+  it('allows getting and setting single preferences', () => {
+    setPref('pageSize', 24);
+    expect(getPref('pageSize')).toBe(24);
+    
+    const raw = JSON.parse(window.localStorage.getItem(PREFS_STORAGE_KEY) || '{}');
+    expect(raw.pageSize).toBe(24);
+  });
+});
diff --git a/src/utils/userPrefs.ts b/src/utils/userPrefs.ts
new file mode 100644
index 0000000..6262b6e
--- /dev/null
+++ b/src/utils/userPrefs.ts
@@ -0,0 +1,86 @@
+export type Theme = 'light' | 'dark' | 'system';
+export type DensityPreference = 'comfortable' | 'compact';
+
+export interface UserPrefs {
+  theme: Theme;
+  density: DensityPreference;
+  pageSize: number;
+}
+
+export const DEFAULT_PREFS: UserPrefs = {
+  theme: 'dark',
+  density: 'comfortable',
+  pageSize: 12,
+};
+
+export const PREFS_STORAGE_KEY = 'callora.prefs';
+
+function migrateLegacyKeys(prefs: Partial<UserPrefs>): Partial<UserPrefs> {
+  const updatedPrefs = { ...prefs };
+  
+  if (typeof window === 'undefined') return updatedPrefs;
+  
+  const legacyTheme = window.localStorage.getItem('callora-theme');
+  if (legacyTheme && !updatedPrefs.theme) {
+    if (['light', 'dark', 'system'].includes(legacyTheme)) {
+      updatedPrefs.theme = legacyTheme as Theme;
+    }
+    window.localStorage.removeItem('callora-theme');
+  }
+
+  const legacyDensity = window.localStorage.getItem('callora.density');
+  if (legacyDensity && !updatedPrefs.density) {
+    if (['comfortable', 'compact'].includes(legacyDensity)) {
+      updatedPrefs.density = legacyDensity as DensityPreference;
+    }
+    window.localStorage.removeItem('callora.density');
+  }
+
+  return updatedPrefs;
+}
+
+export function readAllPrefs(): UserPrefs {
+  if (typeof window === 'undefined') return { ...DEFAULT_PREFS };
+
+  const raw = window.localStorage.getItem(PREFS_STORAGE_KEY);
+  let parsed: Partial<UserPrefs> = {};
+
+  if (raw) {
+    try {
+      parsed = JSON.parse(raw);
+      if (typeof parsed !== 'object' || parsed === null) {
+        parsed = {};
+      }
+    } catch (e) {
+      // Parse failure
+      parsed = {};
+    }
+  }
+
+  const migrated = migrateLegacyKeys(parsed);
+
+  const finalPrefs: UserPrefs = {
+    ...DEFAULT_PREFS,
+    ...migrated,
+  };
+
+  // Ensure any migrations or fixes are persisted immediately
+  if (JSON.stringify(finalPrefs) !== raw && typeof window !== 'undefined') {
+    window.localStorage.setItem(PREFS_STORAGE_KEY, JSON.stringify(finalPrefs));
+  }
+
+  return finalPrefs;
+}
+
+export function getPref<K extends keyof UserPrefs>(key: K): UserPrefs[K] {
+  const prefs = readAllPrefs();
+  return prefs[key];
+}
+
+export function setPref<K extends keyof UserPrefs>(key: K, value: UserPrefs[K]): void {
+  const prefs = readAllPrefs();
+  prefs[key] = value;
+  if (typeof window !== 'undefined') {
+    window.localStorage.setItem(PREFS_STORAGE_KEY, JSON.stringify(prefs));
+  }
+}