diff --git a/js/src/admin/components/EditCustomCssModal.js b/js/src/admin/components/EditCustomCssModal.js
index c7686b085..bd855d545 100644
--- a/js/src/admin/components/EditCustomCssModal.js
+++ b/js/src/admin/components/EditCustomCssModal.js
@@ -2,7 +2,7 @@ import SettingsModal from './SettingsModal';
 
 export default class EditCustomCssModal extends SettingsModal {
   className() {
-    return 'EditCustomCssModal Modal--large';
+    return 'EditCustomCssModal TextareaCodeModal Modal--large';
   }
 
   title() {
diff --git a/js/src/admin/components/EditCustomFooterModal.js b/js/src/admin/components/EditCustomFooterModal.js
index 88d97535e..43cfd29d4 100644
--- a/js/src/admin/components/EditCustomFooterModal.js
+++ b/js/src/admin/components/EditCustomFooterModal.js
@@ -2,7 +2,7 @@ import SettingsModal from './SettingsModal';
 
 export default class EditCustomFooterModal extends SettingsModal {
   className() {
-    return 'EditCustomFooterModal Modal--large';
+    return 'EditCustomFooterModal TextareaCodeModal Modal--large';
   }
 
   title() {
diff --git a/js/src/admin/components/EditCustomHeaderModal.js b/js/src/admin/components/EditCustomHeaderModal.js
index 24625cbd7..11a1f8d4e 100644
--- a/js/src/admin/components/EditCustomHeaderModal.js
+++ b/js/src/admin/components/EditCustomHeaderModal.js
@@ -2,7 +2,7 @@ import SettingsModal from './SettingsModal';
 
 export default class EditCustomHeaderModal extends SettingsModal {
   className() {
-    return 'EditCustomHeaderModal Modal--large';
+    return 'EditCustomHeaderModal TextareaCodeModal Modal--large';
   }
 
   title() {
diff --git a/less/admin/AppearancePage.less b/less/admin/AppearancePage.less
index 18b5a46e7..0e7ba3471 100644
--- a/less/admin/AppearancePage.less
+++ b/less/admin/AppearancePage.less
@@ -37,7 +37,7 @@
   margin-bottom: 15px;
 }
 
-.EditCustomCssModal, .EditCustomHeaderModal {
+.TextareaCodeModal {
   textarea {
     font-family: monospace;
     line-height: 1;