Add background color for title of gleaning nodes

Ref #28

web/themes/custom/geofresco/src/global/_layout.scss

@@ -43,3 +43,9 @@
   height: 12rem;
   background-color: cadetblue;
 }
+
+// Gleanings don't have the same faux-image structure (because they'll never
+// have a featured image) but we still want the title to look about the same.
+.page--content-item--gleaning .page-title {
+  background-color: $gleaning;
+}

web/themes/custom/geofresco/src/global/global.scss

@@ -8,6 +8,14 @@ $green: #478D00;
 $green-gray: #8FB489;
 $offwhite: #F8F8F8;
 
+// No idea where this yellow came from, apparently Bulma, but we never set it
+// yet it is the right color.  Anyway i'm past trying to figure things out.
+// Re-setting it here, just so that we can assign it to Gleanings, below.
+$yellow: #ffdd57;
+
+// A color for each content type
+$gleaning: $yellow;
+
 // Update Bulma's global variables.
 $primary: $green;