diff --git a/client/app/styles/_base.scss b/client/app/styles/_base.scss
index c2d22f2f3..0808d2e0f 100644
--- a/client/app/styles/_base.scss
+++ b/client/app/styles/_base.scss
@@ -1650,7 +1650,7 @@
           // Notes: Firefox gets a bit messy if you try and bubble
           // heights + overflow up (min-height issue + still doesn't work v.well),
           // so this is a bit of a hack.
-          max-height: "calc(100vh - 160px - 160px - 160px)";
+          max-height: calc(100vh - 160px - 160px - 160px);
         }
       }
     }