Fix column header in landing page (regression from #4405) (#4416)

app/javascript/styles/about.scss

@@ -562,6 +562,16 @@
     overflow: hidden;
     box-shadow: 0 0 6px rgba($black, 0.1);
 
+    .column-header {
+      color: inherit;
+      font-family: inherit;
+      font-size: 16px;
+      line-height: inherit;
+      font-weight: inherit;
+      margin: 0;
+      padding: 15px;
+    }
+
     .column {
       padding: 0;
       border-radius: 4px;