diff --git a/_includes/styles/color-palette.scss b/_includes/styles/color-palette.scss
index 468e554..17ed9be 100644
--- a/_includes/styles/color-palette.scss
+++ b/_includes/styles/color-palette.scss
@@ -160,6 +160,7 @@ :root {
   --filter-cyan: var(--tn-dark--filter-08);
   --filter-magenta: var(--tn-dark--filter-10);
   --filter-fg: var(--tn-dark--filter-12);
+  --filter-bg: var(--tn-dark--filter-18);
 }
 
 @media (prefers-color-scheme: light) {
@@ -191,5 +192,6 @@ @media (prefers-color-scheme: light) {
     --filter-cyan: var(--tn-light--filter-07);
     --filter-magenta: var(--tn-light--filter-09);
     --filter-fg: var(--tn-light--filter-10);
+    --filter-bg: var(--tn-light--filter-15);
   }
 }