diff --git a/wwwroot/css/calendar-layout-css.css b/wwwroot/css/calendar-layout-css.css
index 9c48645..ab43acf 100644
--- a/wwwroot/css/calendar-layout-css.css
+++ b/wwwroot/css/calendar-layout-css.css
@@ -56,7 +56,6 @@ swp-header-spacer {
   border-bottom: 1px solid var(--color-border);
   z-index: 5; /* Higher than time-axis to cover it when scrolling */
   position: relative;
-  transition: height 150ms ease; /* Smooth height transitions */
 }
 
 
@@ -274,6 +273,7 @@ swp-allday-container {
   padding: 2px;
   align-items: center;
   overflow: hidden;
+  height: 0px; /* Initial height for Web Animation API */
 }
 
 /* All-day events in containers */