Add tooltip to oki links

pages/index.js

@@ -9,6 +9,7 @@ import Button from '@mui/material/Button'
 import ArrowCircleDownIcon from '@mui/icons-material/ArrowCircleDown'
 import OpenInNewIcon from '@mui/icons-material/OpenInNew'
 import FormHelperText from '@mui/material/FormHelperText'
+import Tooltip from '@mui/material/Tooltip'
 
 import HeadLayout from '../components/head-layout'
 import Footer from '../components/footer'
@@ -73,16 +74,18 @@ export default function Home({errorCode, errorMessage, stats}) {
           <Container>
             <Grid container justifyContent='center' spacing={2}>
               <Grid item>
+              <Tooltip title='asso.oki.re' placement='top' arrow>
                 <Button variant='outlined' endIcon={<OpenInNewIcon />} onClick={() => window.open('https://asso.oki.re/public/members/new.php', '_blank')}>
                   <strong>Adhésion</strong>
                 </Button>
-                <FormHelperText sx={{textAlign: 'center', fontStyle: 'italic'}}>asso.oki.re</FormHelperText>
+              </Tooltip>
               </Grid>
               <Grid item>
+                <Tooltip title='o-k-i.net' placement='top' arrow>
                   <Button variant='outlined' endIcon={<OpenInNewIcon />} onClick={() => window.open('https://o-k-i.net', '_blank')}>
                     <strong>Fédiverse</strong>
                   </Button>
-                <FormHelperText sx={{textAlign: 'center', fontStyle: 'italic'}}>o-k-i.net</FormHelperText>
+                </Tooltip>
               </Grid>
             </Grid>
           </Container>