Implemented basic app with Mantine SegmentedControl

frontend/postcss.config.cjs

@@ -0,0 +1,14 @@
+module.exports = {
+    plugins: {
+        'postcss-preset-mantine': {},
+        'postcss-simple-vars': {
+            variables: {
+                'mantine-breakpoint-xs': '36em',
+                'mantine-breakpoint-sm': '48em',
+                'mantine-breakpoint-md': '62em',
+                'mantine-breakpoint-lg': '75em',
+                'mantine-breakpoint-xl': '88em',
+            },
+        },
+    },
+};