diff --git a/addons/mail/static/src/core/common/core.dark.scss b/addons/mail/static/src/core/common/core.dark.scss
index e9338a17fd7..2f0e3b8d1d1 100644
--- a/addons/mail/static/src/core/common/core.dark.scss
+++ b/addons/mail/static/src/core/common/core.dark.scss
@@ -1,10 +1,3 @@
-.o-discuss-badge {
-    --o-discuss-badge-bg: #{map-get($o-theme-text-colors, 'primary')}; // sync with --o-navbar-badge-bg
-    &.o-muted {
-        --o-discuss-badge-bg: #{$gray-300};
-    }
-}
-
 a.o_mail_redirect, a.o_channel_redirect {
     @include button-variant(rgba($primary, .2), rgba($primary, .2), lighten($link-color, 5%), rgba($primary, .3), rgba($primary, .3), lighten($link-color, 10%));
 }