Extract theme creation

app/src/theme.ts

@@ -0,0 +1,39 @@
+import { createMuiTheme } from "@material-ui/core";
+import { amber } from "@material-ui/core/colors";
+
+const baseTheme = {
+  typography: {
+    body1: {
+      fontSize: '0.9rem',
+    },
+  },
+}
+
+const lightTheme = createMuiTheme({
+  ...baseTheme,
+  palette: {
+    type: 'dark',
+  },
+})
+
+const darkTheme = createMuiTheme({
+  ...baseTheme,
+  palette: {
+    type: 'light',
+    background: {
+      default: '#fafafa',
+    },
+    primary: {
+      main: '#931e2e',
+    },
+    secondary: amber,
+    action: {
+      disabledBackground: '#fafafa',
+    },
+  },
+})
+
+export const themes = {
+  lightTheme,
+  darkTheme,
+}