Add theme toggle and fix header styles

Signed-off-by: Joe Adams <github@joeadams.io>

Author: sysadmind

ui/mantine-ui/package-lock.json

@@ -21,6 +21,7 @@
     "@mantine/core": "^8.3.13",
     "@mantine/hooks": "^8.3.13",
     "@tanstack/react-query": "^5.90.21",
+    "@tabler/icons-react": "^3.36.1",
     "highlight.js": "^11.11.1",
     "react": "^19.1.0",
     "react-dom": "^19.2.4",

ui/mantine-ui/package.json

@@ -1,3 +1,9 @@
+.header {
+  background-color: rgb(65, 73, 81);
+  color: #fff;
+  border-bottom: 1px solid var(--mantine-color-gray-6);
+}
+
 .navMain {
   flex: 1;
 }

ui/mantine-ui/src/components/Header.module.css

@@ -1,5 +1,6 @@
 import { Link, NavLink, Route, Routes } from 'react-router-dom';
 import { AppShell, Button, Group, Menu, Text } from '@mantine/core';
+import { ThemeSelector } from '@/components/ThemeSelector';
 import { AlertsPage } from '@/pages/Alerts.page';
 import { SilencesPage } from '@/pages/Silences.page';
 import classes from './Header.module.css';
@@ -117,6 +118,9 @@ export const Header = () => {
               {navLinks}
             </Group>
           </Group>
+          <Group visibleFrom="xs" wrap="nowrap" gap="xs">
+            <ThemeSelector />
+          </Group>
         </Group>
       </Group>
     </AppShell.Header>

ui/mantine-ui/src/components/Header.tsx

@@ -0,0 +1,31 @@
+import { FC } from 'react';
+import { IconBrightnessFilled, IconMoonFilled, IconSunFilled } from '@tabler/icons-react';
+import { ActionIcon, rem, useMantineColorScheme } from '@mantine/core';
+
+export const ThemeSelector: FC = () => {
+  const { colorScheme, setColorScheme } = useMantineColorScheme();
+  const iconProps = {
+    style: { width: rem(20), height: rem(20), display: 'block' },
+    stroke: 1.5,
+  };
+
+  return (
+    <ActionIcon
+      color="gray"
+      title={`Switch to ${colorScheme === 'light' ? 'dark' : colorScheme === 'dark' ? 'browser-preferred' : 'light'} theme`}
+      aria-label={`Switch to ${colorScheme === 'light' ? 'dark' : colorScheme === 'dark' ? 'browser-preferred' : 'light'} theme`}
+      size={32}
+      onClick={() =>
+        setColorScheme(colorScheme === 'light' ? 'dark' : colorScheme === 'dark' ? 'auto' : 'light')
+      }
+    >
+      {colorScheme === 'light' ? (
+        <IconSunFilled {...iconProps} />
+      ) : colorScheme === 'dark' ? (
+        <IconMoonFilled {...iconProps} />
+      ) : (
+        <IconBrightnessFilled {...iconProps} />
+      )}
+    </ActionIcon>
+  );
+};