feat: add theme constants

- Add COLORS for income, expense, background, etc.
- Add FONTS for regular, small, large sizes

constants/theme.ts

@@ -1,53 +1,17 @@
-/**
- * Below are the colors that are used in the app. The colors are defined in the light and dark mode.
- * There are many other ways to style your app. For example, [Nativewind](https://www.nativewind.dev/), [Tamagui](https://tamagui.dev/), [unistyles](https://reactnativeunistyles.vercel.app), etc.
- */
+export const COLORS = {
+  income: '#4CAF50',
+  expense: '#F44336',
+  background: '#F5F5F5',
+  card: '#FFFFFF',
+  text: '#333333',
+  textSecondary: '#666666',
+  border: '#E0E0E0',
+  primary: '#2196F3',
+} as const;
 
-import { Platform } from 'react-native';
-
-const tintColorLight = '#0a7ea4';
-const tintColorDark = '#fff';
-
-export const Colors = {
-  light: {
-    text: '#11181C',
-    background: '#fff',
-    tint: tintColorLight,
-    icon: '#687076',
-    tabIconDefault: '#687076',
-    tabIconSelected: tintColorLight,
-  },
-  dark: {
-    text: '#ECEDEE',
-    background: '#151718',
-    tint: tintColorDark,
-    icon: '#9BA1A6',
-    tabIconDefault: '#9BA1A6',
-    tabIconSelected: tintColorDark,
-  },
-};
-
-export const Fonts = Platform.select({
-  ios: {
-    /** iOS `UIFontDescriptorSystemDesignDefault` */
-    sans: 'system-ui',
-    /** iOS `UIFontDescriptorSystemDesignSerif` */
-    serif: 'ui-serif',
-    /** iOS `UIFontDescriptorSystemDesignRounded` */
-    rounded: 'ui-rounded',
-    /** iOS `UIFontDescriptorSystemDesignMonospaced` */
-    mono: 'ui-monospace',
-  },
-  default: {
-    sans: 'normal',
-    serif: 'serif',
-    rounded: 'normal',
-    mono: 'monospace',
-  },
-  web: {
-    sans: "system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif",
-    serif: "Georgia, 'Times New Roman', serif",
-    rounded: "'SF Pro Rounded', 'Hiragino Maru Gothic ProN', Meiryo, 'MS PGothic', sans-serif",
-    mono: "SFMono-Regular, Menlo, Monaco, Consolas, 'Liberation Mono', 'Courier New', monospace",
-  },
-});
+export const FONTS = {
+  regular: 16,
+  small: 14,
+  large: 24,
+  xlarge: 32,
+} as const;