refactored css, including some markup changes

app/pages/error/error.css

@@ -0,0 +1,11 @@
+.errorPage {
+  display: flex;
+  justify-content: center;
+  align-items: center;
+  flex-direction: column;
+  text-align: center;
+}
+
+.errorPage__img {
+  margin: 51px 0 71px;
+}

app/pages/error/index.js

@@ -0,0 +1,10 @@
+const html = require('choo/html');
+const assets = require('../../../common/assets');
+
+module.exports = function(state) {
+  return html`
+  <div class="errorPage">
+    <div class="title">${state.translate('errorPageHeader')}</div>
+    <img class="errorPage__img" src="${assets.get('illustration_error.svg')}"/>
+  </div>`;
+};