reducing z-index of header area so it doesn't appear over the mobile menu

opentech/static_src/src/sass/public/components/_wrapper.scss

@@ -234,5 +234,13 @@
         flex-direction: column;
         flex-grow: 1;
         justify-content: flex-end;
+
+        .header--homepage & {
+            position: relative;
+            z-index: 9;
+            align-items: flex-start;
+            justify-content: center;
+            height: 100%;
+        }
     }
 }