make main window flex box so announcement always renders correctly

components/Announcement.js

@@ -56,17 +56,13 @@ function Toast() {
           }
 
           .toast {
+            margin: -4.6rem auto 0;
             padding: 8px 16px;
             color: #fff;
             border: 1px solid #fff;
-            border-radius: 2px;
+            border-radius: 3px;
-            margin-top: -4.6rem;
             animation-name: slide;
             animation-duration: 600ms;
-            margin-left: auto;
-            margin-right: auto;
-            /* fix this to only set max width when necessary (mobile) */
-            max-width: 63vw;
           }
 
           .toast-content {

pages/index.js

@@ -21,7 +21,7 @@ class Index extends React.Component {
 
   render() {
     return (
-      <Page enableHeroText={true}>
+      <Page enableHeroText={true} flex={true}>
         <MetaLinks />
         <Either>
           <EditorContainer router={this.props.router} snippet={this.props.snippet} />