Put button inside div and rearranged some code.

src/components/QuizGame.js

@@ -272,8 +272,6 @@ class QuizGame extends React.Component {
         const { classes } = this.props;
 
         return (
-            <Fragment>
-                {
             // Tabs
             <div className={classes.root}>
                 <Typography variant="headline" align="center">
@@ -281,15 +279,13 @@ class QuizGame extends React.Component {
                         <Quiz quiz={this.state.difficulty} key={this.state.key} />
                     </Grid>
                 </Typography>
-                    </div>
-                }
                 <Typography align="center">
                     <Button variant="contained" color="default" className={classes.button} onClick={this.reset}>
                         Reset
                         <RefreshIcon className={classes.rightIcon} />
                     </Button>
                 </Typography>
-            </Fragment>
+            </div>
         );
     }
 }