Apply grid fixes to new quest form

scss/core/_base.scss

@@ -5,4 +5,12 @@
 
 body {
   background-color: $color-gray-lightest;
+  display: flex;
+  flex-direction: column;
+  justify-content: flex-start;
+  min-height: 100vh;
+
+  > footer {
+    margin-top: auto;
+  }
 }

scss/core/_grid.scss

@@ -13,6 +13,7 @@
     display: flex;
     flex-direction: row;
     flex-wrap: wrap;
+    max-width: $site-max-width;
   }
 }