diff --git a/crates/mdbook-html/front-end/css/variables.css b/crates/mdbook-html/front-end/css/variables.css
index 3854b3a74d..ae287821c0 100644
--- a/crates/mdbook-html/front-end/css/variables.css
+++ b/crates/mdbook-html/front-end/css/variables.css
@@ -327,5 +327,9 @@
         --copy-button-filter: invert(26%) sepia(8%) saturate(575%) hue-rotate(169deg) brightness(87%) contrast(82%);
         /* Same as `--sidebar-active` */
         --copy-button-filter-hover: invert(36%) sepia(70%) saturate(503%) hue-rotate(167deg) brightness(98%) contrast(89%);
+
+        --footnote-highlight: #4079ae;
+
+        --overlay-bg: rgba(33, 40, 48, 0.4);
     }
 }