diff --git a/frontend/app/player/web/managers/DOM/safeCSSRules.ts b/frontend/app/player/web/managers/DOM/safeCSSRules.ts
index a65c0cf6c..ba62ad0db 100644
--- a/frontend/app/player/web/managers/DOM/safeCSSRules.ts
+++ b/frontend/app/player/web/managers/DOM/safeCSSRules.ts
@@ -1,14 +1,15 @@
 import logger from 'App/logger';
 
-export type { PostponedStyleSheet } from './VirtualDOM'
-
-export function insertRule(sheet: CSSStyleSheet | PostponedStyleSheet, msg: { rule: string, index: number }) {
+export function insertRule(
+  sheet: { insertRule: (rule: string, index: number) => void },
+  msg: { rule: string, index: number }
+) {
   try {
     sheet.insertRule(msg.rule, msg.index)
   } catch (e) {
     logger.warn(e, msg)
     try {
-      sheet.insertRule(msg.rule, 0)
+      sheet.insertRule(msg.rule, 0) // TODO: index renumeration in case of subsequent rule deletion
       logger.warn("Inserting rule into 0-index", e, msg)
     } catch (e) {
       logger.warn("Cannot insert rule.", e, msg)
@@ -16,7 +17,10 @@ export function insertRule(sheet: CSSStyleSheet | PostponedStyleSheet, msg: { ru
   }
 }
 
-export function deleteRule(sheet: CSSStyleSheet | PostponedStyleSheet, msg: { index: number }) {
+export function deleteRule(
+  sheet: { deleteRule: (index: number) => void },
+  msg: { index: number }
+) {
   try {
     sheet.deleteRule(msg.index)
   } catch (e) {