diff --git a/src/Umbraco.Web.UI.Client/src/less/canvas-designer.less b/src/Umbraco.Web.UI.Client/src/less/canvas-designer.less
index 095027d86b..e7aa9d859f 100644
--- a/src/Umbraco.Web.UI.Client/src/less/canvas-designer.less
+++ b/src/Umbraco.Web.UI.Client/src/less/canvas-designer.less
@@ -14,7 +14,7 @@ body {
     overflow: hidden;
     height: 100%;
     width: 100%;
-    width: calc(100% - 80px); // 80px is the fixed left menu for toggling the different browser sizes
+    width: ~"(calc(~'100%' - ~'80px'))"; // 80px is the fixed left menu for toggling the different browser sizes
     position: absolute;
     padding: 0;
     margin: 0;