Merge branch 'main' into 164-ui-text-field

front-end/src/styles/_variables.scss

@@ -36,4 +36,12 @@ $upload-stroke: #636363;
   --accent: #BB0808;
   --text-colour: #000000;
   --alt-text: #B3B3B3;
-}
+
+// A map of z-index values for different components
+$z-index: (
+  dropdown: 1,
+  sidebar: 2,
+  success: 3,
+  tooltip: 4,
+  modal: 5,
+);