diff --git a/css/userContent-files/webextension-tweaks/generic_style.css b/css/userContent-files/webextension-tweaks/generic_style.css
index 635c388..c1b8eb7 100644
--- a/css/userContent-files/webextension-tweaks/generic_style.css
+++ b/css/userContent-files/webextension-tweaks/generic_style.css
@@ -251,7 +251,7 @@ url-prefix("moz-extension://{e4a8a97b-f2ed-450b-b12d-ee082ba24781}/src/content/e
     font-weight: 700
   }
   .CodeMirror-merge-gap {
-    background-color: var(--in-content-category-header-background)!important;
+    background-color: var(--theme-sidebar-background)!important;
     border-top: 1px solid!important;
     border-bottom: 1px solid!important;
     border-right: none!important;
diff --git a/userContent.css b/userContent.css
index 88a5de0..bff5d0a 100644
--- a/userContent.css
+++ b/userContent.css
@@ -1347,7 +1347,7 @@ url-prefix("moz-extension://{e4a8a97b-f2ed-450b-b12d-ee082ba24781}/src/content/e
     font-weight: 700
   }
   .CodeMirror-merge-gap {
-    background-color: var(--in-content-category-header-background)!important;
+    background-color: var(--theme-sidebar-background)!important;
     border-top: 1px solid!important;
     border-bottom: 1px solid!important;
     border-right: none!important;