diff --git a/fastn-js/js/dom.js b/fastn-js/js/dom.js
index e75dbe2595..5ffedb52fb 100644
--- a/fastn-js/js/dom.js
+++ b/fastn-js/js/dom.js
@@ -2,6 +2,12 @@ let fastn_dom = {};
 
 fastn_dom.styleClasses = "";
 
+fastn_dom.InternalClass = {
+    FT_COLUMN: 'ft_column',
+    FT_ROW: 'ft_row',
+    FULL: "full",
+};
+
 fastn_dom.codeData = {
     availableThemes: {},
     addedCssFile: []
diff --git a/fastn-js/js/utils.js b/fastn-js/js/utils.js
index 5ec1f080e5..4348e406e4 100644
--- a/fastn-js/js/utils.js
+++ b/fastn-js/js/utils.js
@@ -1,16 +1,15 @@
 let fastn_utils = {
-    ftClassNames: ["ft_column", "ft_row"],
     htmlNode(kind) {
         let node = "div";
         let css = [];
         let attributes = {};
         if (kind === fastn_dom.ElementKind.Column) {
-            css.push("ft_column");
+            css.push(fastn_dom.InternalClass.FT_COLUMN);
         } else if (kind === fastn_dom.ElementKind.Document) {
-            css.push("ft_column");
-            css.push("full");
+            css.push(fastn_dom.InternalClass.FT_COLUMN);
+            css.push(fastn_dom.InternalClass.FULL);
         } else if (kind === fastn_dom.ElementKind.Row) {
-            css.push("ft_row");
+            css.push(fastn_dom.InternalClass.FT_ROW);
         } else if (kind === fastn_dom.ElementKind.IFrame) {
             node = "iframe";
             // To allow fullscreen support
@@ -102,11 +101,12 @@ let fastn_utils = {
         if (ssr) {
             iterativeClassList = iterativeClassList.getClasses();
         }
+        const internalClassNames = Object.values(fastn_dom.InternalClass);
         const classesToRemove = [];
 
         for (const className of iterativeClassList) {
             if (!className.startsWith('__') && 
-                !this.ftClassNames.includes(className) &&
+                !internalClassNames.includes(className) &&
                 className !== extraCodeData?.language &&
                 className !== extraCodeData?.theme
             ) {