chore: allow class and style merging for content (#430)

lib/app/Content.js

@@ -10,9 +10,10 @@ export default {
     }
   },
 
-  render (h, { parent, props }) {
+  render (h, { parent, props, data }) {
     return h(pathToComponentName(parent.$page.path), {
-      class: props.custom ? 'custom' : ''
+      class: [props.custom ? 'custom' : '', data.class, data.staticClass],
+      style: data.style
     })
   }
 }