added custom 404 page

Author: akkisagiraju

src/components/NotFoundComponent.js

@@ -0,0 +1,27 @@
+import React from 'react';
+import ContactStyle from '../styles/Contact';
+import HeroText from '../styles/HeroText';
+import MainContainer from '../styles/MainContainer';
+import { Link } from 'gatsby';
+
+const NotFoundComponent = () => {
+  return (
+    <MainContainer>
+      <ContactStyle>
+        <div className={'content upper-content-section'}>
+          <HeroText className={'main-part'}>Not found </HeroText>
+          <hr className={'contact-page-line'}></hr>
+        </div>
+        <div className={'content lower-content-section'}>
+          <p>No page found at this url.</p>
+          <p>
+            {' '}
+            Please got back to the <Link to="/">homepage.</Link>
+          </p>
+        </div>
+      </ContactStyle>
+    </MainContainer>
+  );
+};
+
+export default NotFoundComponent;

src/pages/404.js

@@ -0,0 +1,15 @@
+import React from 'react';
+import Layout from '../components/Layout/Layout';
+import NotFoundComponent from '../components/NotFoundComponent';
+import Seo from '../components/Seo/Seo';
+
+const NotFound = () => {
+  return (
+    <Layout>
+      <Seo title="Not found" />
+      <NotFoundComponent />
+    </Layout>
+  );
+};
+
+export default NotFound;

src/styles/Contact.js

@@ -137,7 +137,8 @@ const Contact = styled(StandardGrid)`
 
   @media (min-width: 1440px) {
     margin-bottom: 80px;
-    margin-top: 80px;
+    margin-top: 100px;
+    min-height: 38vh;
     margin-right: 0px;
 
     .main-part {