diff --git a/wwwroot/css/calendar-layout-css.css b/wwwroot/css/calendar-layout-css.css
index c96c5da..ffc3fa9 100644
--- a/wwwroot/css/calendar-layout-css.css
+++ b/wwwroot/css/calendar-layout-css.css
@@ -265,6 +265,16 @@ swp-day-header[data-today="true"] swp-day-date {
   margin: 4px auto 0;
 }
 
+/* Border between row 1 and row 2 in week header */
+swp-week-header::after {
+  content: '';
+  grid-column: 1 / -1; /* Span all columns */
+  grid-row: 2; /* Position at start of row 2 */
+  border-top: 1px solid var(--color-grid-line);
+  height: 0;
+  z-index: 1;
+}
+
 /* Orange header sections in row 2 */
 swp-header-section-left {
   grid-column: 1 / 3; /* Span columns 1-2 */