UX: introduce min-height for responsive ads (#170)

assets/javascripts/discourse/templates/components/google-adsense.hbs

@@ -2,7 +2,11 @@
   <div class="google-adsense-label"><h2>{{i18n
         "adplugin.advertisement_label"
       }}</h2></div>
-  <div class="google-adsense-content" style={{adWrapperStyle}}>
+  <div
+    class="google-adsense-content"
+    id={{if isResponsive "google-adsense__responsive"}}
+    style={{adWrapperStyle}}
+  >
     <ins
       class="adsbygoogle"
       style={{adInsStyle}}

assets/stylesheets/adplugin.scss

@@ -18,6 +18,12 @@
   width: 100%;
 }
 
+#google-adsense__responsive {
+  // Google strips styles added to parent wrapper classes, so we use this ID
+  // this sets a minimum height to reduce cumulative layout shift
+  min-height: 200px;
+}
+
 .google-adsense .google-adsense-label {
   width: 728px;
   max-width: 100%;