Can toggle dark theme

geneit_app/src/widgets/DarkThemeButton.tsx

@@ -0,0 +1,19 @@
+import Brightness7Icon from "@mui/icons-material/Brightness7";
+import DarkModeIcon from "@mui/icons-material/DarkMode";
+import { IconButton, Tooltip } from "@mui/material";
+import { useDarkTheme } from "../context_providers/DarkThemeProvider";
+
+export function DarkThemeButton(): React.ReactElement {
+  const darkTheme = useDarkTheme();
+
+  return (
+    <Tooltip title="Activer / désactiver le mode sombre">
+      <IconButton
+        onClick={() => darkTheme.setEnabled(!darkTheme.enabled)}
+        style={{ color: "inherit" }}
+      >
+        {!darkTheme.enabled ? <DarkModeIcon /> : <Brightness7Icon />}
+      </IconButton>
+    </Tooltip>
+  );
+}