Improve responsiveness

src/App.js

@@ -44,8 +44,8 @@ function App() {
 
     <ChakraProvider theme={theme}>
       <Nav></Nav>
-      <Center>
-        <SimpleGrid columns={2} spacing={4}>
+      <Center p={5}>
+        <SimpleGrid columns={{ base: 1, md: 2, lg: 2 }} spacing={4}>
 
           <Heading>Wohnung</Heading>
           <Box></Box>

src/Solimieten.js

@@ -60,7 +60,7 @@ export function FlatSelectionCard({ setSelectedFlat }) {
             <Heading size='md'>Wohnungsauswahl</Heading>
         </CardHeader>
         <CardBody>
-            <Stack spacing={4} w="500px">
+            <Stack spacing={4} >
                 <Select placeholder='Gebäude auswählen' onChange={buildingSelected}>
                     <option value='north'>Nordbau</option>
                     <option value='south'>Südbau</option>