Memories Initial Styles

app styles

import { makeStyles } from '@material-ui/core/styles';

export default makeStyles(() => ({
  appBar: {
    borderRadius: 15,
    margin: '30px 0',
    display: 'flex',
    flexDirection: 'row',
    justifyContent: 'center',
    alignItems: 'center',
  },
  heading: {
    color: 'rgba(0,183,255, 1)',
  },
  image: {
    marginLeft: '15px',
  },
}));

form styles

import { makeStyles } from '@material-ui/core/styles';

export default makeStyles((theme) => ({
  root: {
    '& .MuiTextField-root': {
      margin: theme.spacing(1),
    },
  },
  paper: {
    padding: theme.spacing(2),
  },
  form: {
    display: 'flex',
    flexWrap: 'wrap',
    justifyContent: 'center',
  },
  fileInput: {
    width: '97%',
    margin: '10px 0',
  },
  buttonSubmit: {
    marginBottom: 10,
  },
}));

post styles

import { makeStyles } from '@material-ui/core/styles';

export default makeStyles({
  media: {
    height: 0,
    paddingTop: '56.25%',
    backgroundColor: 'rgba(0, 0, 0, 0.5)',
    backgroundBlendMode: 'darken',
  },
  border: {
    border: 'solid',
  },
  fullHeightCard: {
    height: '100%',
  },
  card: {
    display: 'flex',
    flexDirection: 'column',
    justifyContent: 'space-between',
    borderRadius: '15px',
    height: '100%',
    position: 'relative',
  },
  overlay: {
    position: 'absolute',
    top: '20px',
    left: '20px',
    color: 'white',
  },
  overlay2: {
    position: 'absolute',
    top: '20px',
    right: '20px',
    color: 'white',
  },
  grid: {
    display: 'flex',
  },
  details: {
    display: 'flex',
    justifyContent: 'space-between',
    margin: '20px',
  },
  title: {
    padding: '0 16px',
  },
  cardActions: {
    padding: '0 16px 8px 16px',
    display: 'flex',
    justifyContent: 'space-between',
  },
});

posts styles

import { makeStyles } from '@material-ui/core/styles';

export default makeStyles((theme) => ({
  mainContainer: {
    display: 'flex',
    alignItems: 'center',
  },
  smMargin: {
    margin: theme.spacing(1),
  },
  actionDiv: {
    textAlign: 'center',
  },
}));

new version of mui do not support this, you can use "sx"
they said you should use mui system (npm install @mui/system @emotion/react @emotion/styled), but it works with npm install @mui/material @emotion/react @emotion/styled for me