Implement basic structure

src/layout/Content.tsx

@@ -0,0 +1,14 @@
+import { Box } from '@mui/material';
+import React, { type PropsWithChildren, type ReactElement } from 'react';
+import { TopBar } from './TopBar.tsx';
+
+export type ContentProps = PropsWithChildren;
+
+export function Content({ children }: ContentProps): ReactElement {
+    return (
+        <Box sx={{ width: { xs: '100%', md: '80%' }, margin: 'auto' }}>
+            <TopBar />
+            {children}
+        </Box>
+    );
+}