diff --git a/App.tsx b/App.tsx
index efbcb62..a1d1e04 100644
--- a/App.tsx
+++ b/App.tsx
@@ -1,6 +1,7 @@
 import React, { useEffect, useState } from 'react';
 import { NavigationContainer, LinkingOptions } from '@react-navigation/native';
 import { AuthProvider } from './src/contexts/AuthContext';
+import { AccessibilityProvider } from './src/contexts/AccessibilityContext';
 import { useAuth } from './src/hooks/useAuth';
 import SplashScreen from './src/screens/SplashScreen';
 import AuthNavigator from './src/navigation/AuthNavigator';
@@ -61,18 +62,20 @@ function RootNavigator() {
 
 export default function App() {
   return (
-    <AuthProvider>
-      <NavigationContainer<RootStackParamList>
-        linking={linkingConfig}
-        fallback={
-          <View style={styles.loading}>
-            <ActivityIndicator size="large" />
-          </View>
-        }
-      >
-        <RootNavigator />
-      </NavigationContainer>
-    </AuthProvider>
+    <AccessibilityProvider>
+      <AuthProvider>
+        <NavigationContainer<RootStackParamList>
+          linking={linkingConfig}
+          fallback={
+            <View style={styles.loading}>
+              <ActivityIndicator size="large" />
+            </View>
+          }
+        >
+          <RootNavigator />
+        </NavigationContainer>
+      </AuthProvider>
+    </AccessibilityProvider>
   );
 }
 
diff --git a/jest.config.js b/jest.config.js
index 6716ca1..1cdb148 100644
--- a/jest.config.js
+++ b/jest.config.js
@@ -8,5 +8,6 @@ module.exports = {
     'node_modules/(?!(react-native|@react-native|@react-navigation)/)'
   ],
   testPathIgnorePatterns: ['/node_modules/', '/android/', '/ios/'],
+  setupFiles: ['<rootDir>/jest.setup.js'],
   resetMocks: true,
 };
\ No newline at end of file
diff --git a/jest.setup.js b/jest.setup.js
new file mode 100644
index 0000000..5ede553
--- /dev/null
+++ b/jest.setup.js
@@ -0,0 +1,3 @@
+jest.mock('@react-native-async-storage/async-storage', () =>
+  require('@react-native-async-storage/async-storage/jest/async-storage-mock'),
+);
diff --git a/src/components/HorizontalMenu.tsx b/src/components/HorizontalMenu.tsx
index 79248a7..658930a 100644
--- a/src/components/HorizontalMenu.tsx
+++ b/src/components/HorizontalMenu.tsx
@@ -1,6 +1,8 @@
-import React from 'react';
+import React, { useMemo } from 'react';
 import { ScrollView, TouchableOpacity, Text, StyleSheet } from 'react-native';
-import { Colors, Spacing, FontSize, BorderRadius } from '../theme';
+import { Spacing, FontSize, BorderRadius } from '../theme';
+import { ThemeColors } from '../theme/colors';
+import { useThemeColors, useFontScale } from '../contexts/AccessibilityContext';
 
 interface HorizontalMenuProps {
   items: string[];
@@ -9,11 +11,16 @@ interface HorizontalMenuProps {
 }
 
 export default function HorizontalMenu({ items, selected, onSelect }: HorizontalMenuProps) {
+  const colors = useThemeColors();
+  const fontScale = useFontScale();
+  const styles = useStyles(colors, fontScale);
+
   return (
     <ScrollView
       horizontal
       showsHorizontalScrollIndicator={false}
       contentContainerStyle={styles.container}
+      accessibilityRole="tablist"
     >
       {items.map((item) => {
         const isActive = item === selected;
@@ -22,6 +29,10 @@ export default function HorizontalMenu({ items, selected, onSelect }: Horizontal
             key={item}
             style={[styles.item, isActive && styles.itemActive]}
             onPress={() => onSelect(item)}
+            accessibilityRole="tab"
+            accessibilityLabel={item}
+            accessibilityState={{ selected: isActive }}
+            accessibilityHint={`Filtrar por ${item}`}
           >
             <Text style={[styles.text, isActive && styles.textActive]}>
               {item}
@@ -33,30 +44,36 @@ export default function HorizontalMenu({ items, selected, onSelect }: Horizontal
   );
 }
 
-const styles = StyleSheet.create({
-  container: {
-    paddingHorizontal: Spacing.base,
-    paddingVertical: Spacing.sm,
-    gap: Spacing.sm,
-  },
-  item: {
-    paddingHorizontal: Spacing.base,
-    paddingVertical: Spacing.sm,
-    borderRadius: BorderRadius.xl,
-    backgroundColor: Colors.surface,
-    borderWidth: 1,
-    borderColor: Colors.border,
-  },
-  itemActive: {
-    backgroundColor: Colors.primary,
-    borderColor: Colors.primary,
-  },
-  text: {
-    fontSize: FontSize.md,
-    color: Colors.textSecondary,
-  },
-  textActive: {
-    color: Colors.textOnPrimary,
-    fontWeight: '600',
-  },
-});
+function useStyles(colors: ThemeColors, fontScale: number) {
+  return useMemo(
+    () =>
+      StyleSheet.create({
+        container: {
+          paddingHorizontal: Spacing.base,
+          paddingVertical: Spacing.sm,
+          gap: Spacing.sm,
+        },
+        item: {
+          paddingHorizontal: Spacing.base,
+          paddingVertical: Spacing.sm,
+          borderRadius: BorderRadius.xl,
+          backgroundColor: colors.surface,
+          borderWidth: 1,
+          borderColor: colors.border,
+        },
+        itemActive: {
+          backgroundColor: colors.primary,
+          borderColor: colors.primary,
+        },
+        text: {
+          fontSize: FontSize.md * fontScale,
+          color: colors.textSecondary,
+        },
+        textActive: {
+          color: colors.textOnPrimary,
+          fontWeight: '600',
+        },
+      }),
+    [colors, fontScale],
+  );
+}
diff --git a/src/contexts/AccessibilityContext.tsx b/src/contexts/AccessibilityContext.tsx
new file mode 100644
index 0000000..c55f3bd
--- /dev/null
+++ b/src/contexts/AccessibilityContext.tsx
@@ -0,0 +1,157 @@
+import React, {
+  createContext,
+  useContext,
+  useState,
+  useEffect,
+  useCallback,
+  useMemo,
+  ReactNode,
+} from 'react';
+import AsyncStorage from '@react-native-async-storage/async-storage';
+import { Colors, HighContrastColors, ThemeColors } from '../theme/colors';
+
+export type FontScale = 'normal' | 'grande' | 'maior';
+
+// Multiplicador aplicado à tipografia conforme a preferência do usuário.
+export const FONT_SCALE_FACTOR: Record<FontScale, number> = {
+  normal: 1,
+  grande: 1.2,
+  maior: 1.4,
+};
+
+const FONT_SCALE_LABEL: Record<FontScale, string> = {
+  normal: 'Normal',
+  grande: 'Grande',
+  maior: 'Maior',
+};
+
+const STORAGE_KEY_FONTE = '@App:acessibilidade:fontScale';
+const STORAGE_KEY_CONTRASTE = '@App:acessibilidade:highContrast';
+
+const ORDEM_FONTE: FontScale[] = ['normal', 'grande', 'maior'];
+
+interface AccessibilityContextData {
+  fontScale: FontScale;
+  fontScaleFactor: number;
+  fontScaleLabel: string;
+  highContrast: boolean;
+  isLoading: boolean;
+  colors: ThemeColors;
+  setFontScale(escala: FontScale): Promise<void>;
+  cycleFontScale(): Promise<void>;
+  setHighContrast(ativo: boolean): Promise<void>;
+  toggleHighContrast(): Promise<void>;
+}
+
+const AccessibilityContext = createContext<AccessibilityContextData>(
+  {} as AccessibilityContextData,
+);
+
+interface AccessibilityProviderProps {
+  children: ReactNode;
+}
+
+export const AccessibilityProvider = ({ children }: AccessibilityProviderProps) => {
+  const [fontScale, setFontScaleState] = useState<FontScale>('normal');
+  const [highContrast, setHighContrastState] = useState(false);
+  const [isLoading, setIsLoading] = useState(true);
+
+  useEffect(() => {
+    async function carregarPreferencias() {
+      try {
+        const [fonteSalva, contrasteSalvo] = await Promise.all([
+          AsyncStorage.getItem(STORAGE_KEY_FONTE),
+          AsyncStorage.getItem(STORAGE_KEY_CONTRASTE),
+        ]);
+        if (fonteSalva && fonteSalva in FONT_SCALE_FACTOR) {
+          setFontScaleState(fonteSalva as FontScale);
+        }
+        if (contrasteSalvo === 'true') {
+          setHighContrastState(true);
+        }
+      } catch (error) {
+        console.error(error);
+      } finally {
+        setIsLoading(false);
+      }
+    }
+    carregarPreferencias();
+  }, []);
+
+  const setFontScale = useCallback(async (escala: FontScale) => {
+    setFontScaleState(escala);
+    try {
+      await AsyncStorage.setItem(STORAGE_KEY_FONTE, escala);
+    } catch (error) {
+      console.error(error);
+    }
+  }, []);
+
+  const cycleFontScale = useCallback(async () => {
+    const indiceAtual = ORDEM_FONTE.indexOf(fontScale);
+    const proxima = ORDEM_FONTE[(indiceAtual + 1) % ORDEM_FONTE.length];
+    await setFontScale(proxima);
+  }, [fontScale, setFontScale]);
+
+  const setHighContrast = useCallback(async (ativo: boolean) => {
+    setHighContrastState(ativo);
+    try {
+      await AsyncStorage.setItem(STORAGE_KEY_CONTRASTE, ativo ? 'true' : 'false');
+    } catch (error) {
+      console.error(error);
+    }
+  }, []);
+
+  const toggleHighContrast = useCallback(async () => {
+    await setHighContrast(!highContrast);
+  }, [highContrast, setHighContrast]);
+
+  const value = useMemo<AccessibilityContextData>(
+    () => ({
+      fontScale,
+      fontScaleFactor: FONT_SCALE_FACTOR[fontScale],
+      fontScaleLabel: FONT_SCALE_LABEL[fontScale],
+      highContrast,
+      isLoading,
+      colors: highContrast ? HighContrastColors : Colors,
+      setFontScale,
+      cycleFontScale,
+      setHighContrast,
+      toggleHighContrast,
+    }),
+    [
+      fontScale,
+      highContrast,
+      isLoading,
+      setFontScale,
+      cycleFontScale,
+      setHighContrast,
+      toggleHighContrast,
+    ],
+  );
+
+  return (
+    <AccessibilityContext.Provider value={value}>
+      {children}
+    </AccessibilityContext.Provider>
+  );
+};
+
+export function useAccessibility(): AccessibilityContextData {
+  return useContext(AccessibilityContext);
+}
+
+// Retorna a paleta ativa conforme a preferência de contraste.
+// Faz fallback para a paleta padrão fora do Provider.
+export function useThemeColors(): ThemeColors {
+  const ctx = useContext(AccessibilityContext);
+  return ctx?.colors ?? Colors;
+}
+
+// Retorna o multiplicador de fonte ativo, com fallback seguro (1).
+export function useFontScale(): number {
+  const ctx = useContext(AccessibilityContext);
+  return ctx?.fontScaleFactor ?? 1;
+}
+
+export default AccessibilityContext;
diff --git a/src/contexts/__tests__/AccessibilityContext.test.tsx b/src/contexts/__tests__/AccessibilityContext.test.tsx
new file mode 100644
index 0000000..4c21d21
--- /dev/null
+++ b/src/contexts/__tests__/AccessibilityContext.test.tsx
@@ -0,0 +1,100 @@
+import React from 'react';
+import { Text } from 'react-native';
+import { act, render, screen, waitFor } from '@testing-library/react-native';
+import AsyncStorage from '@react-native-async-storage/async-storage';
+import {
+  AccessibilityProvider,
+  useAccessibility,
+} from '../AccessibilityContext';
+
+jest.mock('@react-native-async-storage/async-storage', () => ({
+  getItem: jest.fn(),
+  setItem: jest.fn(),
+}));
+
+const mockedAsyncStorage = AsyncStorage as jest.Mocked<typeof AsyncStorage>;
+
+let controle: ReturnType<typeof useAccessibility>;
+
+function Sonda() {
+  controle = useAccessibility();
+  return (
+    <Text>
+      {controle.fontScaleLabel}-{controle.highContrast ? 'alto' : 'normal'}
+    </Text>
+  );
+}
+
+function renderizar() {
+  return render(
+    <AccessibilityProvider>
+      <Sonda />
+    </AccessibilityProvider>,
+  );
+}
+
+describe('AccessibilityContext', () => {
+  beforeEach(() => {
+    mockedAsyncStorage.getItem.mockResolvedValue(null);
+    mockedAsyncStorage.setItem.mockResolvedValue();
+  });
+
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  it('usa os valores padrão quando não há nada persistido', async () => {
+    renderizar();
+
+    await waitFor(() => {
+      expect(screen.getByText('Normal-normal')).toBeTruthy();
+    });
+    expect(controle.fontScaleFactor).toBe(1);
+  });
+
+  it('persiste a escolha de alto contraste', async () => {
+    renderizar();
+    await waitFor(() => expect(controle).toBeDefined());
+
+    await act(async () => {
+      await controle.setHighContrast(true);
+    });
+
+    expect(mockedAsyncStorage.setItem).toHaveBeenCalledWith(
+      '@App:acessibilidade:highContrast',
+      'true',
+    );
+    expect(controle.highContrast).toBe(true);
+  });
+
+  it('cicla o tamanho da fonte e persiste', async () => {
+    renderizar();
+    await waitFor(() => expect(controle).toBeDefined());
+
+    await act(async () => {
+      await controle.cycleFontScale();
+    });
+
+    expect(controle.fontScale).toBe('grande');
+    expect(controle.fontScaleFactor).toBeGreaterThan(1);
+    expect(mockedAsyncStorage.setItem).toHaveBeenCalledWith(
+      '@App:acessibilidade:fontScale',
+      'grande',
+    );
+  });
+
+  it('carrega preferências previamente persistidas', async () => {
+    mockedAsyncStorage.getItem.mockImplementation(async (chave: string) => {
+      if (chave === '@App:acessibilidade:fontScale') return 'maior';
+      if (chave === '@App:acessibilidade:highContrast') return 'true';
+      return null;
+    });
+
+    renderizar();
+
+    await waitFor(() => {
+      expect(screen.getByText('Maior-alto')).toBeTruthy();
+    });
+    expect(controle.colors.background).toBeTruthy();
+  });
+});
diff --git a/src/screens/app/ConfiguracoesScreen.tsx b/src/screens/app/ConfiguracoesScreen.tsx
index c8df89e..896bd6d 100644
--- a/src/screens/app/ConfiguracoesScreen.tsx
+++ b/src/screens/app/ConfiguracoesScreen.tsx
@@ -1,4 +1,4 @@
-import React, { useState } from 'react';
+import React, { useMemo, useState } from 'react';
 import {
   View,
   Text,
@@ -10,35 +10,90 @@ import {
   Alert,
 } from 'react-native';
 import Ionicons from 'react-native-vector-icons/Ionicons';
+import { ThemeColors } from '../../theme/colors';
+import { useAccessibility, useThemeColors, useFontScale } from '../../contexts/AccessibilityContext';
 
-function SettingToggle({ label, value, onToggle }: { label: string; value: boolean; onToggle: (v: boolean) => void }) {
+function SettingToggle({
+  label,
+  value,
+  onToggle,
+  colors,
+  fontScale,
+  hint,
+}: {
+  label: string;
+  value: boolean;
+  onToggle: (v: boolean) => void;
+  colors: ThemeColors;
+  fontScale: number;
+  hint?: string;
+}) {
+  const styles = useStyles(colors, fontScale);
   return (
     <View style={styles.toggleRow}>
       <Text style={styles.toggleLabel}>{label}</Text>
       <Switch
         value={value}
         onValueChange={onToggle}
-        trackColor={{ false: '#E0E0E0', true: '#6200EE' }}
-        thumbColor="#FFFFFF"
+        trackColor={{ false: colors.border, true: colors.primary }}
+        thumbColor={colors.textOnPrimary}
+        accessibilityRole="switch"
+        accessibilityLabel={label}
+        accessibilityHint={hint}
+        accessibilityState={{ checked: value }}
       />
     </View>
   );
 }
 
-function SettingOption({ icon, label, value, onPress }: { icon: string; label: string; value?: string; onPress: () => void }) {
+function SettingOption({
+  icon,
+  label,
+  value,
+  onPress,
+  colors,
+  fontScale,
+  hint,
+}: {
+  icon: string;
+  label: string;
+  value?: string;
+  onPress: () => void;
+  colors: ThemeColors;
+  fontScale: number;
+  hint?: string;
+}) {
+  const styles = useStyles(colors, fontScale);
   return (
-    <TouchableOpacity style={styles.optionRow} onPress={onPress} activeOpacity={0.7}>
-      <Ionicons name={icon} size={22} color="#7A869A" />
+    <TouchableOpacity
+      style={styles.optionRow}
+      onPress={onPress}
+      activeOpacity={0.7}
+      accessibilityRole="button"
+      accessibilityLabel={value ? `${label}, ${value}` : label}
+      accessibilityHint={hint}
+    >
+      <Ionicons name={icon} size={22} color={colors.textSecondary} />
       <Text style={styles.optionLabel}>{label}</Text>
       <View style={styles.optionRight}>
         {value && <Text style={styles.optionValue}>{value}</Text>}
-        <Ionicons name="chevron-forward" size={18} color="#9CA3AF" />
+        <Ionicons name="chevron-forward" size={18} color={colors.textLight} />
       </View>
     </TouchableOpacity>
   );
 }
 
 export default function ConfiguracoesScreen() {
+  const colors = useThemeColors();
+  const fontScale = useFontScale();
+  const styles = useStyles(colors, fontScale);
+  const {
+    fontScaleLabel,
+    cycleFontScale,
+    highContrast,
+    setHighContrast,
+  } = useAccessibility();
+
   const [lembretes, setLembretes] = useState(true);
   const [amigos, setAmigos] = useState(false);
   const [conquistas, setConquistas] = useState(true);
@@ -71,80 +126,114 @@ export default function ConfiguracoesScreen() {
     <SafeAreaView style={styles.container}>
       <ScrollView contentContainerStyle={styles.content}>
         <View style={styles.secao}>
-          <Text style={styles.secaoTitulo}>Notificações</Text>
+          <Text style={styles.secaoTitulo} accessibilityRole="header">
+            Notificações
+          </Text>
           <SettingToggle
             label="Lembretes de prática"
             value={lembretes}
             onToggle={setLembretes}
+            colors={colors}
+            fontScale={fontScale}
           />
           <SettingToggle
             label="Atualizações de amigos"
             value={amigos}
             onToggle={setAmigos}
+            colors={colors}
+            fontScale={fontScale}
           />
           <SettingToggle
             label="Conquistas e medalhas"
             value={conquistas}
             onToggle={setConquistas}
+            colors={colors}
+            fontScale={fontScale}
           />
         </View>
 
         <View style={styles.secao}>
-          <Text style={styles.secaoTitulo}>Aparência</Text>
+          <Text style={styles.secaoTitulo} accessibilityRole="header">
+            Aparência
+          </Text>
           <SettingToggle
             label="Tema escuro"
             value={temaEscuro}
             onToggle={setTemaEscuro}
+            colors={colors}
+            fontScale={fontScale}
           />
         </View>
 
         <View style={styles.secao}>
-          <Text style={styles.secaoTitulo}>Vídeo e Armazenamento</Text>
+          <Text style={styles.secaoTitulo} accessibilityRole="header">
+            Vídeo e Armazenamento
+          </Text>
           <SettingOption
             icon="videocam"
             label="Qualidade de vídeo"
             value="Média"
             onPress={handleVideoQuality}
+            colors={colors}
+            fontScale={fontScale}
           />
           <SettingOption
             icon="trash"
             label="Limpar cache"
             onPress={handleClearCache}
+            colors={colors}
+            fontScale={fontScale}
           />
         </View>
 
         <View style={styles.secao}>
-          <Text style={styles.secaoTitulo}>Acessibilidade</Text>
+          <Text style={styles.secaoTitulo} accessibilityRole="header">
+            Acessibilidade
+          </Text>
           <SettingOption
             icon="text"
             label="Tamanho da fonte"
-            value="Normal"
-            onPress={() => {}}
+            value={fontScaleLabel}
+            onPress={cycleFontScale}
+            colors={colors}
+            fontScale={fontScale}
+            hint="Toque para alternar entre Normal, Grande e Maior"
           />
-          <SettingOption
-            icon="contrast"
+          <SettingToggle
             label="Alto contraste"
-            onPress={() => {}}
+            value={highContrast}
+            onToggle={setHighContrast}
+            colors={colors}
+            fontScale={fontScale}
+            hint="Ativa cores de alto contraste para facilitar a leitura"
           />
         </View>
 
         <View style={styles.secao}>
-          <Text style={styles.secaoTitulo}>Sobre</Text>
+          <Text style={styles.secaoTitulo} accessibilityRole="header">
+            Sobre
+          </Text>
           <SettingOption
             icon="information-circle"
             label="Versão do app"
             value="1.0.0"
             onPress={() => {}}
+            colors={colors}
+            fontScale={fontScale}
           />
           <SettingOption
             icon="document-text"
             label="Termos de uso"
             onPress={() => {}}
+            colors={colors}
+            fontScale={fontScale}
           />
           <SettingOption
             icon="shield-checkmark"
             label="Política de privacidade"
             onPress={() => {}}
+            colors={colors}
+            fontScale={fontScale}
           />
         </View>
       </ScrollView>
@@ -152,58 +241,65 @@ export default function ConfiguracoesScreen() {
   );
 }
 
-const styles = StyleSheet.create({
-  container: {
-    flex: 1,
-    backgroundColor: '#FFFFFF',
-  },
-  content: {
-    paddingBottom: 40,
-  },
-  secao: {
-    paddingHorizontal: 20,
-    paddingTop: 20,
-  },
-  secaoTitulo: {
-    fontSize: 13,
-    fontWeight: '600',
-    color: '#7A869A',
-    textTransform: 'uppercase',
-    letterSpacing: 0.5,
-    marginBottom: 12,
-  },
-  toggleRow: {
-    flexDirection: 'row',
-    justifyContent: 'space-between',
-    alignItems: 'center',
-    paddingVertical: 12,
-    borderBottomWidth: 1,
-    borderBottomColor: '#F0F2F5',
-  },
-  toggleLabel: {
-    fontSize: 16,
-    color: '#1A1A1A',
-  },
-  optionRow: {
-    flexDirection: 'row',
-    alignItems: 'center',
-    paddingVertical: 14,
-    borderBottomWidth: 1,
-    borderBottomColor: '#F0F2F5',
-  },
-  optionLabel: {
-    flex: 1,
-    fontSize: 16,
-    color: '#1A1A1A',
-    marginLeft: 12,
-  },
-  optionRight: {
-    flexDirection: 'row',
-    alignItems: 'center',
-    gap: 4,
-  },
-  optionValue: {
-    fontSize: 14,
-    color: '#7A869A',
-  },
-});
+function useStyles(colors: ThemeColors, fontScale: number) {
+  return useMemo(
+    () =>
+      StyleSheet.create({
+        container: {
+          flex: 1,
+          backgroundColor: colors.background,
+        },
+        content: {
+          paddingBottom: 40,
+        },
+        secao: {
+          paddingHorizontal: 20,
+          paddingTop: 20,
+        },
+        secaoTitulo: {
+          fontSize: 13 * fontScale,
+          fontWeight: '600',
+          color: colors.textSecondary,
+          textTransform: 'uppercase',
+          letterSpacing: 0.5,
+          marginBottom: 12,
+        },
+        toggleRow: {
+          flexDirection: 'row',
+          justifyContent: 'space-between',
+          alignItems: 'center',
+          paddingVertical: 12,
+          borderBottomWidth: 1,
+          borderBottomColor: colors.borderLight,
+        },
+        toggleLabel: {
+          flex: 1,
+          fontSize: 16 * fontScale,
+          color: colors.text,
+        },
+        optionRow: {
+          flexDirection: 'row',
+          alignItems: 'center',
+          paddingVertical: 14,
+          borderBottomWidth: 1,
+          borderBottomColor: colors.borderLight,
+        },
+        optionLabel: {
+          flex: 1,
+          fontSize: 16 * fontScale,
+          color: colors.text,
+          marginLeft: 12,
+        },
+        optionRight: {
+          flexDirection: 'row',
+          alignItems: 'center',
+          gap: 4,
+        },
+        optionValue: {
+          fontSize: 14 * fontScale,
+          color: colors.textSecondary,
+        },
+      }),
+    [colors, fontScale],
+  );
+}
diff --git a/src/screens/app/HomeScreen.tsx b/src/screens/app/HomeScreen.tsx
index 82b46d4..d4c121a 100644
--- a/src/screens/app/HomeScreen.tsx
+++ b/src/screens/app/HomeScreen.tsx
@@ -1,8 +1,10 @@
-import React, { useCallback, useEffect, useState } from 'react';
+import React, { useCallback, useEffect, useMemo, useState } from 'react';
 import { View, Text, StyleSheet, TouchableOpacity, FlatList } from 'react-native';
 import { useFocusEffect, useNavigation } from '@react-navigation/native';
 import Ionicons from 'react-native-vector-icons/Ionicons';
-import { Colors, Spacing, FontSize, BorderRadius } from '../../theme';
+import { Spacing, FontSize, BorderRadius } from '../../theme';
+import { ThemeColors } from '../../theme/colors';
+import { useThemeColors, useFontScale } from '../../contexts/AccessibilityContext';
 import { auth } from '../../services/firebase';
 import { getCurrentUserById } from '../../services/models/user';
 import { getCourseModulesOverview, ModuleOverview } from '../../services/models/courseOverview';
@@ -12,21 +14,34 @@ interface CourseCardProps {
   progress: number;
   locked: boolean;
   onPress: () => void;
+  colors: ThemeColors;
+  fontScale: number;
 }
 
-function CourseCard({ title, progress, locked, onPress }: CourseCardProps) {
+function CourseCard({ title, progress, locked, onPress, colors, fontScale }: CourseCardProps) {
   const isCompleted = progress >= 100;
+  const styles = useStyles(colors, fontScale);
+
+  const estado = locked
+    ? 'Bloqueado'
+    : isCompleted
+    ? 'Concluído'
+    : `${progress}% concluído`;
 
   return (
     <TouchableOpacity
       style={[styles.cardContainer, locked && styles.cardLocked]}
       activeOpacity={locked ? 1 : 0.7}
       onPress={locked ? undefined : onPress}
+      accessibilityRole="button"
+      accessibilityLabel={`Módulo ${title}, ${estado}`}
+      accessibilityHint={locked ? 'Módulo bloqueado' : 'Toque para abrir o módulo'}
+      accessibilityState={{ disabled: locked }}
     >
       <View style={styles.headerRow}>
         <Text style={styles.titleText}>{title}</Text>
         {locked ? (
-          <Ionicons name="lock-closed" size={18} color={Colors.textLight} />
+          <Ionicons name="lock-closed" size={18} color={colors.textLight} />
         ) : (
           <Text style={styles.percentageText}>{progress}%</Text>
         )}
@@ -53,6 +68,9 @@ function CourseCard({ title, progress, locked, onPress }: CourseCardProps) {
 }
 
 export default function HomeScreen() {
+  const colors = useThemeColors();
+  const fontScale = useFontScale();
+  const styles = useStyles(colors, fontScale);
   const [modules, setModules] = useState<ModuleOverview[]>([]);
   const [streak, setStreak] = useState(0);
   const navigation = useNavigation();
@@ -95,12 +113,18 @@ export default function HomeScreen() {
 
   return (
     <View style={styles.screenContainer}>
-      <View style={styles.streakContainer}>
-        <Ionicons name="flame" size={24} color={Colors.streak} />
+      <View
+        style={styles.streakContainer}
+        accessibilityRole="text"
+        accessibilityLabel={`${streak} dias de ofensiva`}
+      >
+        <Ionicons name="flame" size={24} color={colors.streak} />
         <Text style={styles.streakText}>{streak} dias de ofensiva</Text>
       </View>
 
-      <Text style={styles.title}>Módulos</Text>
+      <Text style={styles.title} accessibilityRole="header">
+        Módulos
+      </Text>
 
       <FlatList
         data={modules}
@@ -111,6 +135,8 @@ export default function HomeScreen() {
             progress={item.progress}
             locked={item.locked}
             onPress={() => handleCardPress(item.id)}
+            colors={colors}
+            fontScale={fontScale}
           />
         )}
         showsVerticalScrollIndicator={false}
@@ -119,100 +145,106 @@ export default function HomeScreen() {
   );
 }
 
-const styles = StyleSheet.create({
-  screenContainer: {
-    flex: 1,
-    backgroundColor: Colors.background,
-    padding: Spacing.lg,
-  },
-  streakContainer: {
-    flexDirection: 'row',
-    alignItems: 'center',
-    marginBottom: Spacing.base,
-    gap: Spacing.sm,
-  },
-  streakText: {
-    fontSize: FontSize.base,
-    fontWeight: '600',
-    color: Colors.streak,
-  },
-  title: {
-    fontSize: FontSize.title,
-    fontWeight: 'bold',
-    color: Colors.accent,
-    marginBottom: Spacing.lg,
-  },
-  cardContainer: {
-    backgroundColor: Colors.card,
-    borderRadius: BorderRadius.xl,
-    borderWidth: 1.5,
-    borderColor: '#6379F2',
-    paddingVertical: Spacing.base,
-    paddingHorizontal: Spacing.lg,
-    marginBottom: Spacing.lg,
-    shadowColor: '#000',
-    shadowOffset: { width: 0, height: 2 },
-    shadowOpacity: 0.05,
-    shadowRadius: 4,
-    elevation: 2,
-  },
-  cardLocked: {
-    opacity: 0.5,
-  },
-  headerRow: {
-    flexDirection: 'row',
-    justifyContent: 'space-between',
-    alignItems: 'center',
-    marginBottom: Spacing.sm,
-  },
-  titleText: {
-    fontSize: FontSize.base,
-    color: Colors.textSecondary,
-    fontWeight: '500',
-  },
-  percentageText: {
-    fontSize: FontSize.base,
-    color: Colors.textSecondary,
-    fontWeight: '500',
-  },
-  progressBarTrack: {
-    height: 8,
-    backgroundColor: Colors.progressTrack,
-    borderRadius: BorderRadius.sm,
-    marginBottom: Spacing.base,
-    overflow: 'hidden',
-  },
-  progressBarFill: {
-    height: '100%',
-    backgroundColor: Colors.progressFill,
-    borderRadius: BorderRadius.sm,
-  },
-  footer: {
-    alignItems: 'center',
-    justifyContent: 'center',
-  },
-  continueText: {
-    fontSize: FontSize.base,
-    fontWeight: 'bold',
-    color: Colors.primaryDark,
-  },
-  lockedText: {
-    fontSize: FontSize.base,
-    color: Colors.textLight,
-  },
-  completedContainer: {
-    flexDirection: 'row',
-    alignItems: 'center',
-  },
-  completedText: {
-    fontSize: FontSize.base,
-    fontWeight: 'bold',
-    color: Colors.primaryDark,
-  },
-  checkIcon: {
-    fontSize: FontSize.lg,
-    fontWeight: 'bold',
-    color: Colors.success,
-    marginLeft: 6,
-  },
-});
+function useStyles(colors: ThemeColors, fontScale: number) {
+  return useMemo(
+    () =>
+      StyleSheet.create({
+        screenContainer: {
+          flex: 1,
+          backgroundColor: colors.background,
+          padding: Spacing.lg,
+        },
+        streakContainer: {
+          flexDirection: 'row',
+          alignItems: 'center',
+          marginBottom: Spacing.base,
+          gap: Spacing.sm,
+        },
+        streakText: {
+          fontSize: FontSize.base * fontScale,
+          fontWeight: '600',
+          color: colors.streak,
+        },
+        title: {
+          fontSize: FontSize.title * fontScale,
+          fontWeight: 'bold',
+          color: colors.accent,
+          marginBottom: Spacing.lg,
+        },
+        cardContainer: {
+          backgroundColor: colors.card,
+          borderRadius: BorderRadius.xl,
+          borderWidth: 1.5,
+          borderColor: colors.borderAccent,
+          paddingVertical: Spacing.base,
+          paddingHorizontal: Spacing.lg,
+          marginBottom: Spacing.lg,
+          shadowColor: '#000',
+          shadowOffset: { width: 0, height: 2 },
+          shadowOpacity: 0.05,
+          shadowRadius: 4,
+          elevation: 2,
+        },
+        cardLocked: {
+          opacity: 0.5,
+        },
+        headerRow: {
+          flexDirection: 'row',
+          justifyContent: 'space-between',
+          alignItems: 'center',
+          marginBottom: Spacing.sm,
+        },
+        titleText: {
+          fontSize: FontSize.base * fontScale,
+          color: colors.textSecondary,
+          fontWeight: '500',
+        },
+        percentageText: {
+          fontSize: FontSize.base * fontScale,
+          color: colors.textSecondary,
+          fontWeight: '500',
+        },
+        progressBarTrack: {
+          height: 8,
+          backgroundColor: colors.progressTrack,
+          borderRadius: BorderRadius.sm,
+          marginBottom: Spacing.base,
+          overflow: 'hidden',
+        },
+        progressBarFill: {
+          height: '100%',
+          backgroundColor: colors.progressFill,
+          borderRadius: BorderRadius.sm,
+        },
+        footer: {
+          alignItems: 'center',
+          justifyContent: 'center',
+        },
+        continueText: {
+          fontSize: FontSize.base * fontScale,
+          fontWeight: 'bold',
+          color: colors.primaryDark,
+        },
+        lockedText: {
+          fontSize: FontSize.base * fontScale,
+          color: colors.textLight,
+        },
+        completedContainer: {
+          flexDirection: 'row',
+          alignItems: 'center',
+        },
+        completedText: {
+          fontSize: FontSize.base * fontScale,
+          fontWeight: 'bold',
+          color: colors.primaryDark,
+        },
+        checkIcon: {
+          fontSize: FontSize.lg * fontScale,
+          fontWeight: 'bold',
+          color: colors.success,
+          marginLeft: 6,
+        },
+      }),
+    [colors, fontScale],
+  );
+}
diff --git a/src/screens/app/NotificationScreen.tsx b/src/screens/app/NotificationScreen.tsx
index 9c1972f..2ab2883 100644
--- a/src/screens/app/NotificationScreen.tsx
+++ b/src/screens/app/NotificationScreen.tsx
@@ -9,6 +9,8 @@ import {
 } from 'react-native';
 import Ionicons from 'react-native-vector-icons/Ionicons';
 import { Colors, Spacing, BorderRadius, FontSize } from '../../theme';
+import { ThemeColors } from '../../theme/colors';
+import { useThemeColors, useFontScale } from '../../contexts/AccessibilityContext';
 
 type TipoNotificacao = 'lembrete' | 'conquista' | 'social' | 'sistema';
 
@@ -116,6 +118,8 @@ type CartaoProps = {
   onAcao: (item: Notificacao) => void;
   onMarcarLida: (id: string) => void;
   onExcluir: (id: string) => void;
+  colors: ThemeColors;
+  fontScale: number;
 };
 
 function CartaoNotificacao({
@@ -124,8 +128,11 @@ function CartaoNotificacao({
   onAcao,
   onMarcarLida,
   onExcluir,
+  colors,
+  fontScale,
 }: CartaoProps) {
   const config = CONFIG_TIPO[item.tipo];
+  const styles = useStyles(colors, fontScale);
 
   return (
     <TouchableOpacity
@@ -133,6 +140,9 @@ function CartaoNotificacao({
       onPress={() => onLer(item.id)}
       onLongPress={() => onExcluir(item.id)}
       activeOpacity={0.7}
+      accessibilityRole="button"
+      accessibilityLabel={`${item.lida ? 'Lida' : 'Não lida'}. ${item.titulo}. ${item.mensagem}. ${item.tempo}`}
+      accessibilityHint="Toque para marcar como lida. Pressione e segure para excluir."
     >
       <View style={styles.linhaTopo}>
         <View style={[styles.iconeContainer, { backgroundColor: config.cor + '1A' }]}>
@@ -152,7 +162,9 @@ function CartaoNotificacao({
             {item.mensagem}
           </Text>
         </View>
-        {!item.lida && <View style={styles.indicadorNaoLido} />}
+        {!item.lida && (
+          <View style={styles.indicadorNaoLido} accessibilityLabel="Não lida" />
+        )}
       </View>
 
       <View style={styles.acoes}>
@@ -160,6 +172,8 @@ function CartaoNotificacao({
           style={[styles.botaoAcaoPrincipal, { backgroundColor: config.cor + '1A' }]}
           onPress={() => onAcao(item)}
           activeOpacity={0.7}
+          accessibilityRole="button"
+          accessibilityLabel={config.acaoLabel}
         >
           <Ionicons name={config.acaoIcone} size={16} color={config.cor} />
           <Text style={[styles.botaoAcaoTexto, { color: config.cor }]}>
@@ -173,8 +187,10 @@ function CartaoNotificacao({
               style={styles.botaoSecundario}
               onPress={() => onMarcarLida(item.id)}
               activeOpacity={0.7}
+              accessibilityRole="button"
+              accessibilityLabel="Marcar como lida"
             >
-              <Ionicons name="checkmark-done-outline" size={16} color={Colors.textSecondary} />
+              <Ionicons name="checkmark-done-outline" size={16} color={colors.textSecondary} />
               <Text style={styles.botaoSecundarioTexto}>Marcar como lida</Text>
             </TouchableOpacity>
           )}
@@ -182,9 +198,11 @@ function CartaoNotificacao({
             style={styles.botaoSecundario}
             onPress={() => onExcluir(item.id)}
             activeOpacity={0.7}
+            accessibilityRole="button"
+            accessibilityLabel="Excluir notificação"
           >
-            <Ionicons name="trash-outline" size={16} color={Colors.error} />
-            <Text style={[styles.botaoSecundarioTexto, { color: Colors.error }]}>
+            <Ionicons name="trash-outline" size={16} color={colors.error} />
+            <Text style={[styles.botaoSecundarioTexto, { color: colors.error }]}>
               Excluir
             </Text>
           </TouchableOpacity>
@@ -195,6 +213,9 @@ function CartaoNotificacao({
 }
 
 export default function NotificationScreen() {
+  const colors = useThemeColors();
+  const fontScale = useFontScale();
+  const styles = useStyles(colors, fontScale);
   const [filtro, setFiltro] = useState<(typeof FILTROS)[number]>('Todas');
   const [notificacoes, setNotificacoes] = useState<Notificacao[]>(buscarNotificacoesMock);
 
@@ -242,7 +263,12 @@ export default function NotificationScreen() {
     <SafeAreaView style={styles.container}>
       <View style={styles.headerActions}>
         {naoLidas > 0 && (
-          <TouchableOpacity onPress={marcarTodasLidas} activeOpacity={0.7}>
+          <TouchableOpacity
+            onPress={marcarTodasLidas}
+            activeOpacity={0.7}
+            accessibilityRole="button"
+            accessibilityLabel="Marcar todas como lidas"
+          >
             <Text style={styles.marcarTodas}>Marcar todas como lidas</Text>
           </TouchableOpacity>
         )}
@@ -260,6 +286,9 @@ export default function NotificationScreen() {
               style={[styles.filtroChip, filtro === item && styles.filtroChipAtivo]}
               onPress={() => setFiltro(item)}
               activeOpacity={0.7}
+              accessibilityRole="tab"
+              accessibilityLabel={`Filtro ${item}`}
+              accessibilityState={{ selected: filtro === item }}
             >
               <Text
                 style={[styles.filtroTexto, filtro === item && styles.filtroTextoAtivo]}
@@ -279,7 +308,7 @@ export default function NotificationScreen() {
         ItemSeparatorComponent={() => <View style={styles.separador} />}
         ListEmptyComponent={
           <View style={styles.vazio}>
-            <Ionicons name="notifications-off-outline" size={48} color={Colors.border} />
+            <Ionicons name="notifications-off-outline" size={48} color={colors.border} />
             <Text style={styles.vazioTexto}>Nenhuma notificação</Text>
           </View>
         }
@@ -290,6 +319,8 @@ export default function NotificationScreen() {
             onAcao={executarAcao}
             onMarcarLida={marcarComoLida}
             onExcluir={excluir}
+            colors={colors}
+            fontScale={fontScale}
           />
         )}
       />
@@ -297,157 +328,163 @@ export default function NotificationScreen() {
   );
 }
 
-const styles = StyleSheet.create({
-  container: {
-    flex: 1,
-    backgroundColor: Colors.background,
-  },
-  headerActions: {
-    flexDirection: 'row',
-    justifyContent: 'flex-end',
-    paddingHorizontal: Spacing.base,
-    paddingTop: Spacing.sm,
-  },
-  marcarTodas: {
-    fontSize: FontSize.sm,
-    color: Colors.primary,
-    fontWeight: '600',
-  },
-  filtrosWrapper: {
-    borderBottomWidth: 1,
-    borderBottomColor: Colors.borderLight,
-  },
-  filtros: {
-    paddingHorizontal: Spacing.base,
-    paddingVertical: Spacing.md,
-    gap: Spacing.sm,
-  },
-  filtroChip: {
-    paddingHorizontal: Spacing.base,
-    paddingVertical: Spacing.sm,
-    borderRadius: BorderRadius.round,
-    backgroundColor: Colors.surface,
-    marginRight: Spacing.sm,
-  },
-  filtroChipAtivo: {
-    backgroundColor: Colors.primary,
-  },
-  filtroTexto: {
-    fontSize: FontSize.md,
-    color: Colors.textSecondary,
-    fontWeight: '500',
-  },
-  filtroTextoAtivo: {
-    color: Colors.textOnPrimary,
-  },
-  lista: {
-    padding: Spacing.base,
-    paddingBottom: Spacing.lg,
-  },
-  separador: {
-    height: Spacing.md,
-  },
-  notificacao: {
-    backgroundColor: Colors.card,
-    borderRadius: BorderRadius.lg,
-    borderWidth: 1,
-    borderColor: Colors.borderLight,
-    padding: Spacing.base,
-  },
-  notificacaoNaoLida: {
-    backgroundColor: Colors.surface,
-    borderColor: Colors.borderAccent,
-  },
-  linhaTopo: {
-    flexDirection: 'row',
-    alignItems: 'center',
-  },
-  iconeContainer: {
-    width: 44,
-    height: 44,
-    borderRadius: BorderRadius.lg,
-    justifyContent: 'center',
-    alignItems: 'center',
-  },
-  notificacaoInfo: {
-    flex: 1,
-    marginLeft: Spacing.md,
-  },
-  notificacaoHeader: {
-    flexDirection: 'row',
-    justifyContent: 'space-between',
-    alignItems: 'center',
-  },
-  notificacaoTitulo: {
-    flex: 1,
-    fontSize: FontSize.base,
-    fontWeight: '500',
-    color: Colors.text,
-  },
-  textoNaoLido: {
-    fontWeight: '700',
-  },
-  tempo: {
-    fontSize: FontSize.sm,
-    color: Colors.textLight,
-    marginLeft: Spacing.sm,
-  },
-  mensagem: {
-    fontSize: FontSize.md,
-    color: Colors.textSecondary,
-    marginTop: Spacing.xs,
-    lineHeight: 18,
-  },
-  indicadorNaoLido: {
-    width: 8,
-    height: 8,
-    borderRadius: BorderRadius.round,
-    backgroundColor: Colors.primary,
-    marginLeft: Spacing.sm,
-  },
-  acoes: {
-    marginTop: Spacing.md,
-    paddingTop: Spacing.md,
-    borderTopWidth: 1,
-    borderTopColor: Colors.borderLight,
-    gap: Spacing.sm,
-  },
-  botaoAcaoPrincipal: {
-    flexDirection: 'row',
-    alignItems: 'center',
-    alignSelf: 'flex-start',
-    gap: Spacing.xs,
-    paddingHorizontal: Spacing.md,
-    paddingVertical: Spacing.sm,
-    borderRadius: BorderRadius.md,
-  },
-  botaoAcaoTexto: {
-    fontSize: FontSize.md,
-    fontWeight: '600',
-  },
-  acoesSecundarias: {
-    flexDirection: 'row',
-    flexWrap: 'wrap',
-    gap: Spacing.base,
-  },
-  botaoSecundario: {
-    flexDirection: 'row',
-    alignItems: 'center',
-    gap: Spacing.xs,
-    paddingVertical: Spacing.xs,
-  },
-  botaoSecundarioTexto: {
-    fontSize: FontSize.sm,
-    color: Colors.textSecondary,
-    fontWeight: '500',
-  },
-  vazio: {
-    alignItems: 'center',
-    paddingTop: Spacing.xxxl + Spacing.lg,
-  },
-  vazioTexto: {
-    fontSize: FontSize.base,
-    color: Colors.textSecondary,
-    marginTop: Spacing.md,
-  },
-});
+function useStyles(colors: ThemeColors, fontScale: number) {
+  return useMemo(
+    () =>
+      StyleSheet.create({
+        container: {
+          flex: 1,
+          backgroundColor: colors.background,
+        },
+        headerActions: {
+          flexDirection: 'row',
+          justifyContent: 'flex-end',
+          paddingHorizontal: Spacing.base,
+          paddingTop: Spacing.sm,
+        },
+        marcarTodas: {
+          fontSize: FontSize.sm * fontScale,
+          color: colors.primary,
+          fontWeight: '600',
+        },
+        filtrosWrapper: {
+          borderBottomWidth: 1,
+          borderBottomColor: colors.borderLight,
+        },
+        filtros: {
+          paddingHorizontal: Spacing.base,
+          paddingVertical: Spacing.md,
+          gap: Spacing.sm,
+        },
+        filtroChip: {
+          paddingHorizontal: Spacing.base,
+          paddingVertical: Spacing.sm,
+          borderRadius: BorderRadius.round,
+          backgroundColor: colors.surface,
+          marginRight: Spacing.sm,
+        },
+        filtroChipAtivo: {
+          backgroundColor: colors.primary,
+        },
+        filtroTexto: {
+          fontSize: FontSize.md * fontScale,
+          color: colors.textSecondary,
+          fontWeight: '500',
+        },
+        filtroTextoAtivo: {
+          color: colors.textOnPrimary,
+        },
+        lista: {
+          padding: Spacing.base,
+          paddingBottom: Spacing.lg,
+        },
+        separador: {
+          height: Spacing.md,
+        },
+        notificacao: {
+          backgroundColor: colors.card,
+          borderRadius: BorderRadius.lg,
+          borderWidth: 1,
+          borderColor: colors.borderLight,
+          padding: Spacing.base,
+        },
+        notificacaoNaoLida: {
+          backgroundColor: colors.surface,
+          borderColor: colors.borderAccent,
+        },
+        linhaTopo: {
+          flexDirection: 'row',
+          alignItems: 'center',
+        },
+        iconeContainer: {
+          width: 44,
+          height: 44,
+          borderRadius: BorderRadius.lg,
+          justifyContent: 'center',
+          alignItems: 'center',
+        },
+        notificacaoInfo: {
+          flex: 1,
+          marginLeft: Spacing.md,
+        },
+        notificacaoHeader: {
+          flexDirection: 'row',
+          justifyContent: 'space-between',
+          alignItems: 'center',
+        },
+        notificacaoTitulo: {
+          flex: 1,
+          fontSize: FontSize.base * fontScale,
+          fontWeight: '500',
+          color: colors.text,
+        },
+        textoNaoLido: {
+          fontWeight: '700',
+        },
+        tempo: {
+          fontSize: FontSize.sm * fontScale,
+          color: colors.textLight,
+          marginLeft: Spacing.sm,
+        },
+        mensagem: {
+          fontSize: FontSize.md * fontScale,
+          color: colors.textSecondary,
+          marginTop: Spacing.xs,
+          lineHeight: 18 * fontScale,
+        },
+        indicadorNaoLido: {
+          width: 8,
+          height: 8,
+          borderRadius: BorderRadius.round,
+          backgroundColor: colors.primary,
+          marginLeft: Spacing.sm,
+        },
+        acoes: {
+          marginTop: Spacing.md,
+          paddingTop: Spacing.md,
+          borderTopWidth: 1,
+          borderTopColor: colors.borderLight,
+          gap: Spacing.sm,
+        },
+        botaoAcaoPrincipal: {
+          flexDirection: 'row',
+          alignItems: 'center',
+          alignSelf: 'flex-start',
+          gap: Spacing.xs,
+          paddingHorizontal: Spacing.md,
+          paddingVertical: Spacing.sm,
+          borderRadius: BorderRadius.md,
+        },
+        botaoAcaoTexto: {
+          fontSize: FontSize.md * fontScale,
+          fontWeight: '600',
+        },
+        acoesSecundarias: {
+          flexDirection: 'row',
+          flexWrap: 'wrap',
+          gap: Spacing.base,
+        },
+        botaoSecundario: {
+          flexDirection: 'row',
+          alignItems: 'center',
+          gap: Spacing.xs,
+          paddingVertical: Spacing.xs,
+        },
+        botaoSecundarioTexto: {
+          fontSize: FontSize.sm * fontScale,
+          color: colors.textSecondary,
+          fontWeight: '500',
+        },
+        vazio: {
+          alignItems: 'center',
+          paddingTop: Spacing.xxxl + Spacing.lg,
+        },
+        vazioTexto: {
+          fontSize: FontSize.base * fontScale,
+          color: colors.textSecondary,
+          marginTop: Spacing.md,
+        },
+      }),
+    [colors, fontScale],
+  );
+}
diff --git a/src/screens/app/PerfilScreen.tsx b/src/screens/app/PerfilScreen.tsx
index 903dc89..7142437 100644
--- a/src/screens/app/PerfilScreen.tsx
+++ b/src/screens/app/PerfilScreen.tsx
@@ -1,15 +1,28 @@
-import React, { useCallback, useState } from 'react';
+import React, { useCallback, useMemo, useState } from 'react';
 import { View, Text, StyleSheet, TouchableOpacity, ScrollView, Image } from 'react-native';
 import { useFocusEffect, useNavigation } from '@react-navigation/native';
 import Ionicons from 'react-native-vector-icons/Ionicons';
 import { auth } from '../../services/firebase';
 import { getCurrentUserById, UserProfile } from '../../services/models/user';
 import { signOutUser } from '../../services/auth';
-import { Colors, Spacing, FontSize, BorderRadius } from '../../theme';
+import { Spacing, FontSize, BorderRadius } from '../../theme';
+import { ThemeColors } from '../../theme/colors';
+import { useThemeColors, useFontScale } from '../../contexts/AccessibilityContext';
 
-function ProfileInfoRow({ label, value }: { label: string; value: string }) {
+function ProfileInfoRow({
+  label,
+  value,
+  colors,
+  fontScale,
+}: {
+  label: string;
+  value: string;
+  colors: ThemeColors;
+  fontScale: number;
+}) {
+  const styles = useStyles(colors, fontScale);
   return (
-    <View style={styles.infoRow}>
+    <View style={styles.infoRow} accessibilityLabel={`${label}: ${value}`}>
       <Text style={styles.infoLabel}>{label}</Text>
       <Text style={styles.infoValue}>{value}</Text>
     </View>
@@ -17,6 +30,9 @@ function ProfileInfoRow({ label, value }: { label: string; value: string }) {
 }
 
 export default function PerfilScreen() {
+  const colors = useThemeColors();
+  const fontScale = useFontScale();
+  const styles = useStyles(colors, fontScale);
   const navigation = useNavigation();
   const [profile, setProfile] = useState<UserProfile | null>(null);
 
@@ -44,63 +60,89 @@ export default function PerfilScreen() {
       <View style={styles.avatarSection}>
         <View style={styles.avatar}>
           {profile?.profilePictureUrl ? (
-            <Image source={{ uri: profile.profilePictureUrl }} style={styles.avatarImage} />
+            <Image
+              source={{ uri: profile.profilePictureUrl }}
+              style={styles.avatarImage}
+              accessibilityLabel={`Foto de perfil de ${name}`}
+            />
           ) : (
-            <Ionicons name="person" size={48} color={Colors.textOnPrimary} />
+            <Ionicons name="person" size={48} color={colors.textOnPrimary} />
           )}
         </View>
-        <Text style={styles.name}>{name}</Text>
+        <Text style={styles.name} accessibilityRole="header">
+          {name}
+        </Text>
         <Text style={styles.email}>{email}</Text>
       </View>
 
       <View style={styles.statsRow}>
-        <View style={styles.statBox}>
+        <View style={styles.statBox} accessibilityLabel={`${profile?.xp ?? 0} XP total`}>
           <Text style={styles.statValue}>{profile?.xp ?? 0}</Text>
           <Text style={styles.statLabel}>XP Total</Text>
         </View>
-        <View style={styles.statBox}>
+        <View
+          style={styles.statBox}
+          accessibilityLabel={`Ofensiva de ${profile?.streak?.current ?? 0} dias`}
+        >
           <Text style={styles.statValue}>{profile?.streak?.current ?? 0}</Text>
           <Text style={styles.statLabel}>Ofensiva</Text>
         </View>
       </View>
 
       <View style={styles.infoCard}>
-        <Text style={styles.infoTitle}>Informações pessoais</Text>
-        <ProfileInfoRow label="Telefone" value={phone} />
-        <ProfileInfoRow label="Gênero" value={gender} />
-        <ProfileInfoRow label="Nascimento" value={birthDate} />
+        <Text style={styles.infoTitle} accessibilityRole="header">
+          Informações pessoais
+        </Text>
+        <ProfileInfoRow label="Telefone" value={phone} colors={colors} fontScale={fontScale} />
+        <ProfileInfoRow label="Gênero" value={gender} colors={colors} fontScale={fontScale} />
+        <ProfileInfoRow label="Nascimento" value={birthDate} colors={colors} fontScale={fontScale} />
       </View>
 
       <View style={styles.menuSection}>
         <TouchableOpacity
           style={styles.menuItem}
           onPress={() => navigation.navigate('EditProfile')}
+          accessibilityRole="button"
+          accessibilityLabel="Editar Perfil"
+          accessibilityHint="Abre a tela de edição do perfil"
         >
-          <Ionicons name="create-outline" size={22} color={Colors.primary} />
+          <Ionicons name="create-outline" size={22} color={colors.primary} />
           <Text style={styles.menuText}>Editar Perfil</Text>
-          <Ionicons name="chevron-forward" size={20} color={Colors.textLight} />
+          <Ionicons name="chevron-forward" size={20} color={colors.textLight} />
         </TouchableOpacity>
 
         <TouchableOpacity
           style={styles.menuItem}
           onPress={() => navigation.navigate('ChangePassword')}
+          accessibilityRole="button"
+          accessibilityLabel="Alterar Senha"
+          accessibilityHint="Abre a tela de alteração de senha"
         >
-          <Ionicons name="lock-closed-outline" size={22} color={Colors.primary} />
+          <Ionicons name="lock-closed-outline" size={22} color={colors.primary} />
           <Text style={styles.menuText}>Alterar Senha</Text>
-          <Ionicons name="chevron-forward" size={20} color={Colors.textLight} />
+          <Ionicons name="chevron-forward" size={20} color={colors.textLight} />
         </TouchableOpacity>
 
         <TouchableOpacity
           style={styles.menuItem}
           onPress={() => navigation.navigate('BugReport')}
+          accessibilityRole="button"
+          accessibilityLabel="Reportar Bug"
+          accessibilityHint="Abre a tela para reportar um problema"
         >
-          <Ionicons name="bug-outline" size={22} color={Colors.primary} />
+          <Ionicons name="bug-outline" size={22} color={colors.primary} />
           <Text style={styles.menuText}>Reportar Bug</Text>
-          <Ionicons name="chevron-forward" size={20} color={Colors.textLight} />
+          <Ionicons name="chevron-forward" size={20} color={colors.textLight} />
         </TouchableOpacity>
 
-        <TouchableOpacity style={styles.logoutButton} onPress={handleLogout}>
-          <Ionicons name="log-out-outline" size={22} color={Colors.error} />
+        <TouchableOpacity
+          style={styles.logoutButton}
+          onPress={handleLogout}
+          accessibilityRole="button"
+          accessibilityLabel="Sair"
+          accessibilityHint="Encerra a sessão e volta para a tela de login"
+        >
+          <Ionicons name="log-out-outline" size={22} color={colors.error} />
           <Text style={styles.logoutText}>Sair</Text>
         </TouchableOpacity>
       </View>
@@ -108,123 +150,129 @@ export default function PerfilScreen() {
   );
 }
 
-const styles = StyleSheet.create({
-  container: {
-    flex: 1,
-    backgroundColor: Colors.background,
-  },
-  content: {
-    padding: Spacing.lg,
-  },
-  avatarSection: {
-    alignItems: 'center',
-    marginBottom: Spacing.xl,
-  },
-  avatar: {
-    width: 96,
-    height: 96,
-    borderRadius: 48,
-    backgroundColor: Colors.primary,
-    justifyContent: 'center',
-    alignItems: 'center',
-    marginBottom: Spacing.md,
-    overflow: 'hidden',
-  },
-  avatarImage: {
-    width: '100%',
-    height: '100%',
-  },
-  name: {
-    fontSize: FontSize.xl,
-    fontWeight: 'bold',
-    color: Colors.text,
-  },
-  email: {
-    fontSize: FontSize.md,
-    color: Colors.textSecondary,
-    marginTop: Spacing.xs,
-  },
-  statsRow: {
-    flexDirection: 'row',
-    justifyContent: 'space-around',
-    backgroundColor: Colors.surface,
-    borderRadius: BorderRadius.lg,
-    padding: Spacing.base,
-    marginBottom: Spacing.xl,
-  },
-  statBox: {
-    alignItems: 'center',
-  },
-  statValue: {
-    fontSize: FontSize.xxl,
-    fontWeight: 'bold',
-    color: Colors.primary,
-  },
-  statLabel: {
-    fontSize: FontSize.sm,
-    color: Colors.textSecondary,
-    marginTop: Spacing.xs,
-  },
-  menuSection: {
-    gap: Spacing.sm,
-  },
-  infoCard: {
-    backgroundColor: Colors.card,
-    borderRadius: BorderRadius.lg,
-    borderWidth: 1,
-    borderColor: Colors.border,
-    padding: Spacing.base,
-    marginBottom: Spacing.xl,
-    gap: Spacing.sm,
-  },
-  infoTitle: {
-    fontSize: FontSize.base,
-    fontWeight: '600',
-    color: Colors.text,
-    marginBottom: Spacing.xs,
-  },
-  infoRow: {
-    gap: Spacing.xs,
-  },
-  infoLabel: {
-    fontSize: FontSize.sm,
-    color: Colors.textSecondary,
-  },
-  infoValue: {
-    fontSize: FontSize.base,
-    color: Colors.text,
-    fontWeight: '500',
-  },
-  menuItem: {
-    flexDirection: 'row',
-    alignItems: 'center',
-    backgroundColor: Colors.card,
-    borderRadius: BorderRadius.lg,
-    borderWidth: 1,
-    borderColor: Colors.border,
-    padding: Spacing.base,
-    gap: Spacing.md,
-  },
-  menuText: {
-    flex: 1,
-    fontSize: FontSize.base,
-    color: Colors.text,
-  },
-  logoutButton: {
-    flexDirection: 'row',
-    alignItems: 'center',
-    backgroundColor: Colors.card,
-    borderRadius: BorderRadius.lg,
-    borderWidth: 1,
-    borderColor: Colors.error,
-    padding: Spacing.base,
-    gap: Spacing.md,
-    marginTop: Spacing.md,
-  },
-  logoutText: {
-    flex: 1,
-    fontSize: FontSize.base,
-    color: Colors.error,
-    fontWeight: '600',
-  },
-});
+function useStyles(colors: ThemeColors, fontScale: number) {
+  return useMemo(
+    () =>
+      StyleSheet.create({
+        container: {
+          flex: 1,
+          backgroundColor: colors.background,
+        },
+        content: {
+          padding: Spacing.lg,
+        },
+        avatarSection: {
+          alignItems: 'center',
+          marginBottom: Spacing.xl,
+        },
+        avatar: {
+          width: 96,
+          height: 96,
+          borderRadius: 48,
+          backgroundColor: colors.primary,
+          justifyContent: 'center',
+          alignItems: 'center',
+          marginBottom: Spacing.md,
+          overflow: 'hidden',
+        },
+        avatarImage: {
+          width: '100%',
+          height: '100%',
+        },
+        name: {
+          fontSize: FontSize.xl * fontScale,
+          fontWeight: 'bold',
+          color: colors.text,
+        },
+        email: {
+          fontSize: FontSize.md * fontScale,
+          color: colors.textSecondary,
+          marginTop: Spacing.xs,
+        },
+        statsRow: {
+          flexDirection: 'row',
+          justifyContent: 'space-around',
+          backgroundColor: colors.surface,
+          borderRadius: BorderRadius.lg,
+          padding: Spacing.base,
+          marginBottom: Spacing.xl,
+        },
+        statBox: {
+          alignItems: 'center',
+        },
+        statValue: {
+          fontSize: FontSize.xxl * fontScale,
+          fontWeight: 'bold',
+          color: colors.primary,
+        },
+        statLabel: {
+          fontSize: FontSize.sm * fontScale,
+          color: colors.textSecondary,
+          marginTop: Spacing.xs,
+        },
+        menuSection: {
+          gap: Spacing.sm,
+        },
+        infoCard: {
+          backgroundColor: colors.card,
+          borderRadius: BorderRadius.lg,
+          borderWidth: 1,
+          borderColor: colors.border,
+          padding: Spacing.base,
+          marginBottom: Spacing.xl,
+          gap: Spacing.sm,
+        },
+        infoTitle: {
+          fontSize: FontSize.base * fontScale,
+          fontWeight: '600',
+          color: colors.text,
+          marginBottom: Spacing.xs,
+        },
+        infoRow: {
+          gap: Spacing.xs,
+        },
+        infoLabel: {
+          fontSize: FontSize.sm * fontScale,
+          color: colors.textSecondary,
+        },
+        infoValue: {
+          fontSize: FontSize.base * fontScale,
+          color: colors.text,
+          fontWeight: '500',
+        },
+        menuItem: {
+          flexDirection: 'row',
+          alignItems: 'center',
+          backgroundColor: colors.card,
+          borderRadius: BorderRadius.lg,
+          borderWidth: 1,
+          borderColor: colors.border,
+          padding: Spacing.base,
+          gap: Spacing.md,
+        },
+        menuText: {
+          flex: 1,
+          fontSize: FontSize.base * fontScale,
+          color: colors.text,
+        },
+        logoutButton: {
+          flexDirection: 'row',
+          alignItems: 'center',
+          backgroundColor: colors.card,
+          borderRadius: BorderRadius.lg,
+          borderWidth: 1,
+          borderColor: colors.error,
+          padding: Spacing.base,
+          gap: Spacing.md,
+          marginTop: Spacing.md,
+        },
+        logoutText: {
+          flex: 1,
+          fontSize: FontSize.base * fontScale,
+          color: colors.error,
+          fontWeight: '600',
+        },
+      }),
+    [colors, fontScale],
+  );
+}
diff --git a/src/screens/auth/LoginScreen.tsx b/src/screens/auth/LoginScreen.tsx
index b48aaee..a2c1bf5 100644
--- a/src/screens/auth/LoginScreen.tsx
+++ b/src/screens/auth/LoginScreen.tsx
@@ -1,4 +1,4 @@
-import React, { useState } from 'react';
+import React, { useMemo, useState } from 'react';
 import {
   View,
   Text,
@@ -14,7 +14,9 @@ import {
 import { AuthScreenProps } from '../../@types/navigation';
 import { signInWithEmail } from '../../services/models/user';
 import { isUserAuthenticated } from '../../services/auth';
-import { Colors, Spacing, FontSize, BorderRadius } from '../../theme';
+import { Spacing, FontSize, BorderRadius } from '../../theme';
+import { ThemeColors } from '../../theme/colors';
+import { useThemeColors, useFontScale } from '../../contexts/AccessibilityContext';
 import Ionicons from 'react-native-vector-icons/Ionicons';
 
 function getLoginErrorMessage(error: unknown) {
@@ -36,6 +38,9 @@ function getLoginErrorMessage(error: unknown) {
 }
 
 export default function LoginScreen({ navigation }: AuthScreenProps<'Login'>) {
+  const colors = useThemeColors();
+  const fontScale = useFontScale();
+  const styles = useStyles(colors, fontScale);
   const [email, setEmail] = useState('');
   const [password, setPassword] = useState('');
   const [showPassword, setShowPassword] = useState(false);
@@ -67,15 +72,25 @@ export default function LoginScreen({ navigation }: AuthScreenProps<'Login'>) {
     >
       <ScrollView contentContainerStyle={styles.scroll} keyboardShouldPersistTaps="handled">
         <View style={styles.container}>
-          <Text style={styles.title}>Login</Text>
+          <Text style={styles.title} accessibilityRole="header">
+            Login
+          </Text>
 
           {/* Social buttons */}
           <View style={styles.socialRow}>
-            <TouchableOpacity style={styles.socialButton}>
+            <TouchableOpacity
+              style={styles.socialButton}
+              accessibilityRole="button"
+              accessibilityLabel="Entrar com Facebook"
+            >
               <Ionicons name="logo-facebook" size={22} color="#1877F2" />
               <Text style={styles.socialText}>Facebook</Text>
             </TouchableOpacity>
-            <TouchableOpacity style={styles.socialButton}>
+            <TouchableOpacity
+              style={styles.socialButton}
+              accessibilityRole="button"
+              accessibilityLabel="Entrar com Google"
+            >
               <Ionicons name="logo-google" size={22} color="#EA4335" />
               <Text style={styles.socialText}>Google</Text>
             </TouchableOpacity>
@@ -92,11 +107,13 @@ export default function LoginScreen({ navigation }: AuthScreenProps<'Login'>) {
           <TextInput
             style={styles.input}
             placeholder="Email"
-            placeholderTextColor={Colors.textSecondary}
+            placeholderTextColor={colors.textSecondary}
             value={email}
             onChangeText={setEmail}
             keyboardType="email-address"
             autoCapitalize="none"
+            accessibilityLabel="Email"
+            accessibilityHint="Digite seu endereço de email"
           />
 
           {/* Password */}
@@ -104,16 +121,23 @@ export default function LoginScreen({ navigation }: AuthScreenProps<'Login'>) {
             <TextInput
               style={styles.passwordInput}
               placeholder="Senha"
-              placeholderTextColor={Colors.textSecondary}
+              placeholderTextColor={colors.textSecondary}
               value={password}
               onChangeText={setPassword}
               secureTextEntry={!showPassword}
+              accessibilityLabel="Senha"
+              accessibilityHint="Digite sua senha"
             />
-            <TouchableOpacity onPress={() => setShowPassword(!showPassword)} style={styles.eyeIcon}>
+            <TouchableOpacity
+              onPress={() => setShowPassword(!showPassword)}
+              style={styles.eyeIcon}
+              accessibilityRole="button"
+              accessibilityLabel={showPassword ? 'Ocultar senha' : 'Mostrar senha'}
+            >
               <Ionicons
                 name={showPassword ? 'eye-outline' : 'eye-off-outline'}
                 size={22}
-                color={Colors.textSecondary}
+                color={colors.textSecondary}
               />
             </TouchableOpacity>
           </View>
@@ -122,6 +146,8 @@ export default function LoginScreen({ navigation }: AuthScreenProps<'Login'>) {
           <TouchableOpacity
             onPress={() => navigation.navigate('ForgotPassword')}
             style={styles.forgotRow}
+            accessibilityRole="button"
+            accessibilityLabel="Esqueceu a senha?"
           >
             <Text style={styles.forgotText}>Esqueceu a senha?</Text>
           </TouchableOpacity>
@@ -131,16 +157,23 @@ export default function LoginScreen({ navigation }: AuthScreenProps<'Login'>) {
             style={[styles.button, loading && styles.buttonDisabled]}
             onPress={handleLogin}
             disabled={loading}
+            accessibilityRole="button"
+            accessibilityLabel="Entrar"
+            accessibilityState={{ disabled: loading, busy: loading }}
           >
             {loading ? (
-              <ActivityIndicator color={Colors.textOnPrimary} />
+              <ActivityIndicator color={colors.textOnPrimary} />
             ) : (
               <Text style={styles.buttonText}>Log In</Text>
             )}
           </TouchableOpacity>
 
           {/* Register link */}
-          <TouchableOpacity onPress={() => navigation.navigate('Register')}>
+          <TouchableOpacity
+            onPress={() => navigation.navigate('Register')}
+            accessibilityRole="button"
+            accessibilityLabel="Não tem uma conta? Cadastre-se"
+          >
             <Text style={styles.registerText}>
               Não tem uma conta?{' '}
               <Text style={styles.registerLink}>Cadastre-se</Text>
@@ -152,112 +185,118 @@ export default function LoginScreen({ navigation }: AuthScreenProps<'Login'>) {
   );
 }
 
-const styles = StyleSheet.create({
-  flex: { flex: 1, backgroundColor: Colors.background },
-  scroll: { flexGrow: 1 },
-  container: {
-    flex: 1,
-    paddingHorizontal: Spacing.xl,
-    paddingTop: Spacing.xxxl + Spacing.xl,
-    paddingBottom: Spacing.xxl,
-  },
-  title: {
-    fontSize: FontSize.title,
-    fontWeight: 'bold',
-    color: Colors.accent,
-    marginBottom: 80,
-  },
-  socialRow: {
-    flexDirection: 'row',
-    gap: Spacing.md,
-    marginBottom: Spacing.xl,
-  },
-  socialButton: {
-    flex: 1,
-    flexDirection: 'row',
-    alignItems: 'center',
-    justifyContent: 'center',
-    gap: Spacing.sm,
-    backgroundColor: Colors.surface,
-    paddingVertical: Spacing.md,
-    borderRadius: BorderRadius.lg,
-  },
-  socialText: {
-    fontSize: FontSize.base,
-    color: Colors.text,
-    fontWeight: '500',
-  },
-  divider: {
-    flexDirection: 'row',
-    alignItems: 'center',
-    marginBottom: Spacing.xl,
-  },
-  dividerLine: {
-    flex: 1,
-    height: 1,
-    backgroundColor: Colors.border,
-  },
-  dividerText: {
-    marginHorizontal: Spacing.md,
-    color: Colors.textSecondary,
-    fontSize: FontSize.base,
-  },
-  input: {
-    backgroundColor: Colors.surface,
-    borderRadius: BorderRadius.lg,
-    paddingHorizontal: Spacing.base,
-    paddingVertical: Spacing.md,
-    fontSize: FontSize.base,
-    color: Colors.text,
-    marginBottom: Spacing.md,
-    height: 56,
-  },
-  passwordContainer: {
-    flexDirection: 'row',
-    alignItems: 'center',
-    backgroundColor: Colors.surface,
-    borderRadius: BorderRadius.lg,
-    height: 56,
-    paddingHorizontal: Spacing.base,
-  },
-  passwordInput: {
-    flex: 1,
-    fontSize: FontSize.base,
-    color: Colors.text,
-  },
-  eyeIcon: {
-    padding: Spacing.xs,
-  },
-  forgotRow: {
-    alignSelf: 'flex-end',
-    marginTop: Spacing.sm,
-    marginBottom: Spacing.xl,
-  },
-  forgotText: {
-    fontSize: FontSize.sm,
-    color: Colors.textSecondary,
-  },
-  button: {
-    backgroundColor: Colors.accent,
-    borderRadius: 14,
-    height: 60,
-    alignItems: 'center',
-    justifyContent: 'center',
-    marginBottom: Spacing.xl,
-  },
-  buttonDisabled: { opacity: 0.7 },
-  buttonText: {
-    color: Colors.textOnPrimary,
-    fontSize: FontSize.base,
-    fontWeight: '700',
-  },
-  registerText: {
-    textAlign: 'center',
-    fontSize: FontSize.base,
-    color: Colors.text,
-  },
-  registerLink: {
-    color: Colors.accent,
-    fontWeight: '600',
-  },
-});
+function useStyles(colors: ThemeColors, fontScale: number) {
+  return useMemo(
+    () =>
+      StyleSheet.create({
+        flex: { flex: 1, backgroundColor: colors.background },
+        scroll: { flexGrow: 1 },
+        container: {
+          flex: 1,
+          paddingHorizontal: Spacing.xl,
+          paddingTop: Spacing.xxxl + Spacing.xl,
+          paddingBottom: Spacing.xxl,
+        },
+        title: {
+          fontSize: FontSize.title * fontScale,
+          fontWeight: 'bold',
+          color: colors.accent,
+          marginBottom: 80,
+        },
+        socialRow: {
+          flexDirection: 'row',
+          gap: Spacing.md,
+          marginBottom: Spacing.xl,
+        },
+        socialButton: {
+          flex: 1,
+          flexDirection: 'row',
+          alignItems: 'center',
+          justifyContent: 'center',
+          gap: Spacing.sm,
+          backgroundColor: colors.surface,
+          paddingVertical: Spacing.md,
+          borderRadius: BorderRadius.lg,
+        },
+        socialText: {
+          fontSize: FontSize.base * fontScale,
+          color: colors.text,
+          fontWeight: '500',
+        },
+        divider: {
+          flexDirection: 'row',
+          alignItems: 'center',
+          marginBottom: Spacing.xl,
+        },
+        dividerLine: {
+          flex: 1,
+          height: 1,
+          backgroundColor: colors.border,
+        },
+        dividerText: {
+          marginHorizontal: Spacing.md,
+          color: colors.textSecondary,
+          fontSize: FontSize.base * fontScale,
+        },
+        input: {
+          backgroundColor: colors.surface,
+          borderRadius: BorderRadius.lg,
+          paddingHorizontal: Spacing.base,
+          paddingVertical: Spacing.md,
+          fontSize: FontSize.base * fontScale,
+          color: colors.text,
+          marginBottom: Spacing.md,
+          height: 56,
+        },
+        passwordContainer: {
+          flexDirection: 'row',
+          alignItems: 'center',
+          backgroundColor: colors.surface,
+          borderRadius: BorderRadius.lg,
+          height: 56,
+          paddingHorizontal: Spacing.base,
+        },
+        passwordInput: {
+          flex: 1,
+          fontSize: FontSize.base * fontScale,
+          color: colors.text,
+        },
+        eyeIcon: {
+          padding: Spacing.xs,
+        },
+        forgotRow: {
+          alignSelf: 'flex-end',
+          marginTop: Spacing.sm,
+          marginBottom: Spacing.xl,
+        },
+        forgotText: {
+          fontSize: FontSize.sm * fontScale,
+          color: colors.textSecondary,
+        },
+        button: {
+          backgroundColor: colors.accent,
+          borderRadius: 14,
+          height: 60,
+          alignItems: 'center',
+          justifyContent: 'center',
+          marginBottom: Spacing.xl,
+        },
+        buttonDisabled: { opacity: 0.7 },
+        buttonText: {
+          color: colors.textOnPrimary,
+          fontSize: FontSize.base * fontScale,
+          fontWeight: '700',
+        },
+        registerText: {
+          textAlign: 'center',
+          fontSize: FontSize.base * fontScale,
+          color: colors.text,
+        },
+        registerLink: {
+          color: colors.accent,
+          fontWeight: '600',
+        },
+      }),
+    [colors, fontScale],
+  );
+}
diff --git a/src/screens/auth/RegisterScreen.tsx b/src/screens/auth/RegisterScreen.tsx
index 9c1a285..8315cee 100644
--- a/src/screens/auth/RegisterScreen.tsx
+++ b/src/screens/auth/RegisterScreen.tsx
@@ -1,4 +1,4 @@
-import React, { useState } from 'react';
+import React, { useMemo, useState } from 'react';
 import {
   View,
   Text,
@@ -15,6 +15,8 @@ import { AuthScreenProps } from '../../@types/navigation';
 import { registerUserWithEmail } from '../../services/models/user';
 import { validatePasswordStrength, PasswordStrength } from '../../services/auth';
 import { Colors, Spacing, FontSize, BorderRadius } from '../../theme';
+import { ThemeColors } from '../../theme/colors';
+import { useThemeColors, useFontScale } from '../../contexts/AccessibilityContext';
 import Ionicons from 'react-native-vector-icons/Ionicons';
 
 const FORCA_CONFIG: Record<PasswordStrength, { rotulo: string; cor: string; preenchimento: number }> = {
@@ -24,6 +26,9 @@ const FORCA_CONFIG: Record<PasswordStrength, { rotulo: string; cor: string; pree
 };
 
 export default function RegisterScreen({ navigation }: AuthScreenProps<'Register'>) {
+  const colors = useThemeColors();
+  const fontScale = useFontScale();
+  const styles = useStyles(colors, fontScale);
   const [name, setName] = useState('');
   const [email, setEmail] = useState('');
   const [password, setPassword] = useState('');
@@ -81,15 +86,25 @@ export default function RegisterScreen({ navigation }: AuthScreenProps<'Register
     >
       <ScrollView contentContainerStyle={styles.scroll} keyboardShouldPersistTaps="handled">
         <View style={styles.container}>
-          <Text style={styles.title}>Cadastro</Text>
+          <Text style={styles.title} accessibilityRole="header">
+            Cadastro
+          </Text>
 
           {/* Social buttons */}
           <View style={styles.socialRow}>
-            <TouchableOpacity style={styles.socialButton}>
+            <TouchableOpacity
+              style={styles.socialButton}
+              accessibilityRole="button"
+              accessibilityLabel="Cadastrar com Facebook"
+            >
               <Ionicons name="logo-facebook" size={22} color="#1877F2" />
               <Text style={styles.socialText}>Facebook</Text>
             </TouchableOpacity>
-            <TouchableOpacity style={styles.socialButton}>
+            <TouchableOpacity
+              style={styles.socialButton}
+              accessibilityRole="button"
+              accessibilityLabel="Cadastrar com Google"
+            >
               <Ionicons name="logo-google" size={22} color="#EA4335" />
               <Text style={styles.socialText}>Google</Text>
             </TouchableOpacity>
@@ -106,34 +121,45 @@ export default function RegisterScreen({ navigation }: AuthScreenProps<'Register
           <TextInput
             style={styles.input}
             placeholder="Nome"
-            placeholderTextColor={Colors.textSecondary}
+            placeholderTextColor={colors.textSecondary}
             value={name}
             onChangeText={setName}
             autoCapitalize="words"
+            accessibilityLabel="Nome"
+            accessibilityHint="Digite seu nome completo"
           />
           <TextInput
             style={styles.input}
             placeholder="Email/Telefone"
-            placeholderTextColor={Colors.textSecondary}
+            placeholderTextColor={colors.textSecondary}
             value={email}
             onChangeText={setEmail}
             keyboardType="email-address"
             autoCapitalize="none"
+            accessibilityLabel="Email ou telefone"
+            accessibilityHint="Digite seu email ou telefone"
           />
           <View style={styles.passwordContainer}>
             <TextInput
               style={styles.passwordInput}
               placeholder="Senha"
-              placeholderTextColor={Colors.textSecondary}
+              placeholderTextColor={colors.textSecondary}
               value={password}
               onChangeText={setPassword}
               secureTextEntry={!showPassword}
+              accessibilityLabel="Senha"
+              accessibilityHint="Crie uma senha forte"
             />
-            <TouchableOpacity onPress={() => setShowPassword(!showPassword)} style={styles.eyeIcon}>
+            <TouchableOpacity
+              onPress={() => setShowPassword(!showPassword)}
+              style={styles.eyeIcon}
+              accessibilityRole="button"
+              accessibilityLabel={showPassword ? 'Ocultar senha' : 'Mostrar senha'}
+            >
               <Ionicons
                 name={showPassword ? 'eye-outline' : 'eye-off-outline'}
                 size={22}
-                color={Colors.textSecondary}
+                color={colors.textSecondary}
               />
             </TouchableOpacity>
           </View>
@@ -169,9 +195,12 @@ export default function RegisterScreen({ navigation }: AuthScreenProps<'Register
             style={styles.termsRow}
             onPress={() => setAcceptedTerms(!acceptedTerms)}
             activeOpacity={0.7}
+            accessibilityRole="checkbox"
+            accessibilityLabel="Eu concordo com os Termos de Serviço e Política de Privacidade"
+            accessibilityState={{ checked: acceptedTerms }}
           >
             <View style={[styles.checkbox, acceptedTerms && styles.checkboxChecked]}>
-              {acceptedTerms && <Ionicons name="checkmark" size={14} color={Colors.textOnPrimary} />}
+              {acceptedTerms && <Ionicons name="checkmark" size={14} color={colors.textOnPrimary} />}
             </View>
             <Text style={styles.termsText}>
               Eu concordo com os{' '}
@@ -186,16 +215,23 @@ export default function RegisterScreen({ navigation }: AuthScreenProps<'Register
             style={[styles.button, loading && styles.buttonDisabled]}
             onPress={handleRegister}
             disabled={loading}
+            accessibilityRole="button"
+            accessibilityLabel="Criar Conta"
+            accessibilityState={{ disabled: loading, busy: loading }}
           >
             {loading ? (
-              <ActivityIndicator color={Colors.textOnPrimary} />
+              <ActivityIndicator color={colors.textOnPrimary} />
             ) : (
               <Text style={styles.buttonText}>Criar Conta</Text>
             )}
           </TouchableOpacity>
 
           {/* Login link */}
-          <TouchableOpacity onPress={() => navigation.navigate('Login')}>
+          <TouchableOpacity
+            onPress={() => navigation.navigate('Login')}
+            accessibilityRole="button"
+            accessibilityLabel="Já tem uma conta? Entrar"
+          >
             <Text style={styles.loginText}>
               Já tem uma conta?{' '}
               <Text style={styles.loginLink}>Entrar</Text>
@@ -207,162 +243,168 @@ export default function RegisterScreen({ navigation }: AuthScreenProps<'Register
   );
 }
 
-const styles = StyleSheet.create({
-  flex: { flex: 1, backgroundColor: Colors.background },
-  scroll: { flexGrow: 1 },
-  container: {
-    flex: 1,
-    paddingHorizontal: Spacing.xl,
-    paddingTop: Spacing.xxxl + Spacing.xl,
-    paddingBottom: Spacing.xxl,
-  },
-  title: {
-    fontSize: FontSize.title,
-    fontWeight: 'bold',
-    color: Colors.accent,
-    marginBottom: Spacing.xxxl,
-  },
-  socialRow: {
-    flexDirection: 'row',
-    gap: Spacing.md,
-    marginBottom: Spacing.xl,
-  },
-  socialButton: {
-    flex: 1,
-    flexDirection: 'row',
-    alignItems: 'center',
-    justifyContent: 'center',
-    gap: Spacing.sm,
-    backgroundColor: Colors.surface,
-    paddingVertical: Spacing.md,
-    borderRadius: BorderRadius.lg,
-  },
-  socialText: {
-    fontSize: FontSize.base,
-    color: Colors.text,
-    fontWeight: '500',
-  },
-  divider: {
-    flexDirection: 'row',
-    alignItems: 'center',
-    marginBottom: Spacing.xl,
-  },
-  dividerLine: {
-    flex: 1,
-    height: 1,
-    backgroundColor: Colors.border,
-  },
-  dividerText: {
-    marginHorizontal: Spacing.md,
-    color: Colors.textSecondary,
-    fontSize: FontSize.base,
-  },
-  input: {
-    backgroundColor: Colors.surface,
-    borderRadius: BorderRadius.lg,
-    paddingHorizontal: Spacing.base,
-    paddingVertical: Spacing.md,
-    fontSize: FontSize.base,
-    color: Colors.text,
-    marginBottom: Spacing.md,
-    height: 56,
-  },
-  passwordContainer: {
-    flexDirection: 'row',
-    alignItems: 'center',
-    backgroundColor: Colors.surface,
-    borderRadius: BorderRadius.lg,
-    marginBottom: Spacing.base,
-    height: 56,
-    paddingHorizontal: Spacing.base,
-  },
-  passwordInput: {
-    flex: 1,
-    fontSize: FontSize.base,
-    color: Colors.text,
-  },
-  eyeIcon: {
-    padding: Spacing.xs,
-  },
-  strengthContainer: {
-    marginBottom: Spacing.base,
-  },
-  strengthBarTrack: {
-    height: 6,
-    borderRadius: BorderRadius.round,
-    backgroundColor: Colors.progressTrack,
-    overflow: 'hidden',
-  },
-  strengthBarFill: {
-    height: '100%',
-    borderRadius: BorderRadius.round,
-  },
-  strengthLabel: {
-    marginTop: Spacing.xs,
-    fontSize: FontSize.sm,
-    fontWeight: '600',
-  },
-  strengthHints: {
-    marginTop: Spacing.xs,
-    gap: 2,
-  },
-  strengthHint: {
-    fontSize: FontSize.sm,
-    color: Colors.textSecondary,
-    lineHeight: 18,
-  },
-  termsRow: {
-    flexDirection: 'row',
-    alignItems: 'flex-start',
-    gap: Spacing.md,
-    marginBottom: Spacing.xl,
-  },
-  checkbox: {
-    width: 22,
-    height: 22,
-    borderRadius: BorderRadius.sm,
-    borderWidth: 1.5,
-    borderColor: Colors.border,
-    alignItems: 'center',
-    justifyContent: 'center',
-    marginTop: 2,
-    flexShrink: 0,
-  },
-  checkboxChecked: {
-    backgroundColor: Colors.accent,
-    borderColor: Colors.accent,
-  },
-  termsText: {
-    flex: 1,
-    fontSize: FontSize.sm,
-    color: Colors.text,
-    lineHeight: 20,
-  },
-  termsLink: {
-    color: Colors.accent,
-    fontWeight: '500',
-  },
-  button: {
-    backgroundColor: Colors.accent,
-    borderRadius: 14,
-    height: 60,
-    alignItems: 'center',
-    justifyContent: 'center',
-    marginBottom: Spacing.xl,
-  },
-  buttonDisabled: { opacity: 0.7 },
-  buttonText: {
-    color: Colors.textOnPrimary,
-    fontSize: FontSize.base,
-    fontWeight: '700',
-  },
-  loginText: {
-    textAlign: 'left',
-    fontSize: FontSize.base,
-    color: Colors.text,
-  },
-  loginLink: {
-    color: Colors.accent,
-    fontWeight: '600',
-  },
-});
+function useStyles(colors: ThemeColors, fontScale: number) {
+  return useMemo(
+    () =>
+      StyleSheet.create({
+        flex: { flex: 1, backgroundColor: colors.background },
+        scroll: { flexGrow: 1 },
+        container: {
+          flex: 1,
+          paddingHorizontal: Spacing.xl,
+          paddingTop: Spacing.xxxl + Spacing.xl,
+          paddingBottom: Spacing.xxl,
+        },
+        title: {
+          fontSize: FontSize.title * fontScale,
+          fontWeight: 'bold',
+          color: colors.accent,
+          marginBottom: Spacing.xxxl,
+        },
+        socialRow: {
+          flexDirection: 'row',
+          gap: Spacing.md,
+          marginBottom: Spacing.xl,
+        },
+        socialButton: {
+          flex: 1,
+          flexDirection: 'row',
+          alignItems: 'center',
+          justifyContent: 'center',
+          gap: Spacing.sm,
+          backgroundColor: colors.surface,
+          paddingVertical: Spacing.md,
+          borderRadius: BorderRadius.lg,
+        },
+        socialText: {
+          fontSize: FontSize.base * fontScale,
+          color: colors.text,
+          fontWeight: '500',
+        },
+        divider: {
+          flexDirection: 'row',
+          alignItems: 'center',
+          marginBottom: Spacing.xl,
+        },
+        dividerLine: {
+          flex: 1,
+          height: 1,
+          backgroundColor: colors.border,
+        },
+        dividerText: {
+          marginHorizontal: Spacing.md,
+          color: colors.textSecondary,
+          fontSize: FontSize.base * fontScale,
+        },
+        input: {
+          backgroundColor: colors.surface,
+          borderRadius: BorderRadius.lg,
+          paddingHorizontal: Spacing.base,
+          paddingVertical: Spacing.md,
+          fontSize: FontSize.base * fontScale,
+          color: colors.text,
+          marginBottom: Spacing.md,
+          height: 56,
+        },
+        passwordContainer: {
+          flexDirection: 'row',
+          alignItems: 'center',
+          backgroundColor: colors.surface,
+          borderRadius: BorderRadius.lg,
+          marginBottom: Spacing.base,
+          height: 56,
+          paddingHorizontal: Spacing.base,
+        },
+        passwordInput: {
+          flex: 1,
+          fontSize: FontSize.base * fontScale,
+          color: colors.text,
+        },
+        eyeIcon: {
+          padding: Spacing.xs,
+        },
+        strengthContainer: {
+          marginBottom: Spacing.base,
+        },
+        strengthBarTrack: {
+          height: 6,
+          borderRadius: BorderRadius.round,
+          backgroundColor: colors.progressTrack,
+          overflow: 'hidden',
+        },
+        strengthBarFill: {
+          height: '100%',
+          borderRadius: BorderRadius.round,
+        },
+        strengthLabel: {
+          marginTop: Spacing.xs,
+          fontSize: FontSize.sm * fontScale,
+          fontWeight: '600',
+        },
+        strengthHints: {
+          marginTop: Spacing.xs,
+          gap: 2,
+        },
+        strengthHint: {
+          fontSize: FontSize.sm * fontScale,
+          color: colors.textSecondary,
+          lineHeight: 18 * fontScale,
+        },
+        termsRow: {
+          flexDirection: 'row',
+          alignItems: 'flex-start',
+          gap: Spacing.md,
+          marginBottom: Spacing.xl,
+        },
+        checkbox: {
+          width: 22,
+          height: 22,
+          borderRadius: BorderRadius.sm,
+          borderWidth: 1.5,
+          borderColor: colors.border,
+          alignItems: 'center',
+          justifyContent: 'center',
+          marginTop: 2,
+          flexShrink: 0,
+        },
+        checkboxChecked: {
+          backgroundColor: colors.accent,
+          borderColor: colors.accent,
+        },
+        termsText: {
+          flex: 1,
+          fontSize: FontSize.sm * fontScale,
+          color: colors.text,
+          lineHeight: 20 * fontScale,
+        },
+        termsLink: {
+          color: colors.accent,
+          fontWeight: '500',
+        },
+        button: {
+          backgroundColor: colors.accent,
+          borderRadius: 14,
+          height: 60,
+          alignItems: 'center',
+          justifyContent: 'center',
+          marginBottom: Spacing.xl,
+        },
+        buttonDisabled: { opacity: 0.7 },
+        buttonText: {
+          color: colors.textOnPrimary,
+          fontSize: FontSize.base * fontScale,
+          fontWeight: '700',
+        },
+        loginText: {
+          textAlign: 'left',
+          fontSize: FontSize.base * fontScale,
+          color: colors.text,
+        },
+        loginLink: {
+          color: colors.accent,
+          fontWeight: '600',
+        },
+      }),
+    [colors, fontScale],
+  );
+}
diff --git a/src/theme/colors.ts b/src/theme/colors.ts
index 9b9d6d2..016a56b 100644
--- a/src/theme/colors.ts
+++ b/src/theme/colors.ts
@@ -29,3 +29,40 @@ export const Colors = {
   progressTrack: '#F0F2F5',
   progressFill: '#2D4CC8',
 } as const;
+
+export type ThemeColors = { [K in keyof typeof Colors]: string };
+
+// Paleta de alto contraste (WCAG 2.2 AA).
+// Fundo claro com textos quase pretos e elementos saturados escuros,
+// garantindo razão de contraste alta para baixa visão.
+export const HighContrastColors: ThemeColors = {
+  primary: '#3A00B8',
+  primaryDark: '#1A237E',
+  accent: '#0B3CC1',
+  error: '#B00020',
+  success: '#0B6E2E',
+  warning: '#8A4B00',
+
+  background: '#FFFFFF',
+  surface: '#F2F2F2',
+  card: '#FFFFFF',
+
+  text: '#000000',
+  textSecondary: '#1F1F1F',
+  textLight: '#3D3D3D',
+  textOnPrimary: '#FFFFFF',
+
+  border: '#000000',
+  borderLight: '#5C5C5C',
+  borderAccent: '#0B3CC1',
+
+  tabActive: '#3A00B8',
+  tabInactive: '#3D3D3D',
+
+  podium: '#3A00B8',
+  gold: '#7A5C00',
+  streak: '#A33A00',
+
+  progressTrack: '#D6D6D6',
+  progressFill: '#1A237E',
+};