text: import React from 'react';
  import PropTypes from 'prop-types';
  import AppBar from '@material-ui/core/AppBar';
  import Toolbar from '@material-ui/core/Toolbar';
  import Typography from '@material-ui/core/Typography';
  import Paper from '@material-ui/core/Paper';
  import Grid from '@material-ui/core/Grid';
  import Button from '@material-ui/core/Button';
  import TextField from '@material-ui/core/TextField';
  import Tooltip from '@material-ui/core/Tooltip';
  import IconButton from '@material-ui/core/IconButton';
  import {withStyles} from '@material-ui/core/styles';
  import SearchIcon from '@material-ui/icons/Search';
  import RefreshIcon from '@material-ui/icons/Refresh';
  
  const styles = theme => ({
    paper: {
      maxWidth: 936,
      margin: 'auto',
      overflow: 'hidden',
    },
    searchBar: {
      borderBottom: '1px solid rgba(0, 0, 0, 0.12)',
    },
    searchInput: {
      fontSize: theme.typography.fontSize,
    },
    block: {
      display: 'block',
    },
    addUser: {
      marginRight: theme.spacing(1),
    },
    contentWrapper: {
      margin: '40px 16px',
    },
  });
  
  function Overview(props) {
    const {classes} = props;
  
    return (
      <Paper className={classes.paper}>
        <AppBar className={classes.searchBar} position="static" color="default" elevation={0}>
          <Toolbar>
            <Grid container spacing={2} alignItems="center">
              <Grid item>
                <SearchIcon className={classes.block} color="inherit" />
              </Grid>
              <Grid item xs>
                <TextField
                  fullWidth
                  placeholder="Search by email address, phone number, or user UID"
                  InputProps={{
                    disableUnderline: true,
                    className: classes.searchInput,
                  }}
                />
              </Grid>
              <Grid item>
                <Button variant="contained" color="primary" className={classes.addUser}>
                  Add user
                </Button>
                <Tooltip title="Reload">
                  <IconButton>
                    <RefreshIcon className={classes.block} color="inherit" />
                  </IconButton>
                </Tooltip>
              </Grid>
            </Grid>
          </Toolbar>
        </AppBar>
        <div className={classes.contentWrapper}>
          <Typography color="textSecondary" align="center">
            TEST
          </Typography>
        </div>
      </Paper>
    );
  }
  
  Overview.propTypes = {
    classes: PropTypes.object.isRequired,
  };
  
  export default withStyles(styles)(Overview);