refactor: use const for colours and override default styles

striker-ui/theme/index.ts

@@ -1,20 +1,25 @@
 import createMuiTheme, { Theme } from '@material-ui/core/styles/createMuiTheme';
-import { PANEL_BACKGROUND } from '../lib/consts/DEFAULT_THEME';
+import {
+  PANEL_BACKGROUND,
+  TEXT,
+  PURPLE_OFF,
+  RED_ON,
+} from '../lib/consts/DEFAULT_THEME';
 
 const theme: Theme = createMuiTheme({
   palette: {
     primary: {
-      main: '#343434',
-      light: '#3E78B2',
+      main: PANEL_BACKGROUND,
     },
     secondary: {
-      main: '#343434',
+      main: TEXT,
     },
     background: {
       paper: PANEL_BACKGROUND,
     },
   },
   typography: {
+    fontFamily: 'Roboto',
     fontSize: 14,
   },
   overrides: {
@@ -24,8 +29,14 @@ const theme: Theme = createMuiTheme({
       },
       track: {
         borderRadius: 0,
+        backgroundColor: PURPLE_OFF,
+        '$checked$checked + &': {
+          // Controls checked color for the track
+          backgroundColor: RED_ON,
+        },
       },
       thumb: {
+        color: TEXT,
         borderRadius: 0,
       },
     },