diff --git a/frontend/less/dark-vertical/variables.less b/frontend/less/dark-vertical/variables.less
index 8069a7dc7c..160ce7c1b5 100644
--- a/frontend/less/dark-vertical/variables.less
+++ b/frontend/less/dark-vertical/variables.less
@@ -85,7 +85,7 @@
 
 @calendar-today-bg-value: #3e3a35;
 @calendar-border-value: #747272;
-@calendar-busy-bg-value: #2e2e2e;
+@calendar-busy-bg-value: #221f1f;
 
 @label-color-value: #dfdfdf;
 @label-default-bg-value: #727070;