diff --git a/wwwroot/css/calendar-layout-css.css b/wwwroot/css/calendar-layout-css.css
index 80663fa..0ccc57c 100644
--- a/wwwroot/css/calendar-layout-css.css
+++ b/wwwroot/css/calendar-layout-css.css
@@ -164,6 +164,7 @@ swp-bottom-middle-spacer {
   background: #f0f0f0;
   border-top: 2px solid #333;
   overflow: hidden;
+  position: relative;
 }
 
 
@@ -302,7 +303,11 @@ swp-time-grid::before {
 /* Grid lines */
 swp-grid-lines {
   position: absolute;
-  inset: 0;
+  top: 0;
+  left: 0;
+  right: 0;
+  bottom: 0;
+  min-width: 1750px; /* Match day-columns width */
   pointer-events: none;
   z-index: var(--z-grid);
   background-image: repeating-linear-gradient(