src/components/pages/NotFound.js

-import React, { Component } from "react";
-import { Button, Container, Header, Icon, Segment } from "semantic-ui-react";
+import { Button, Container, Header, Icon, Segment } from 'semantic-ui-react';
+import React, { Component } from 'react';
 
 export default class NotFound extends Component {
   render() {
@@ -12,10 +12,10 @@ export default class NotFound extends Component {
               content="404 - A keresett oldal nem található!"
               inverted
               style={{
-                fontSize: "3em",
-                fontWeight: "normal",
+                fontSize: '3em',
+                fontWeight: 'normal',
                 marginBottom: 0,
-                marginTop: "0.5em"
+                marginTop: '0.5em',
               }}
             />
             <Button
@@ -23,9 +23,9 @@ export default class NotFound extends Component {
               primary
               size="huge"
               style={{
-                fontSize: "2em",
-                marginTop: "1em",
-                marginBottom: "1em"
+                fontSize: '2em',
+                marginTop: '1em',
+                marginBottom: '1em',
               }}
             >
               Vissza a Főoldalra

src/config.js.temp

-export const APIKEY = '';

src/index.css

-body {
-  margin: 0;
-  padding: 0;
-  font-family: sans-serif;
-}