diff --git a/header.php b/header.php
index 325e4104..04346f9d 100644
--- a/header.php
+++ b/header.php
@@ -14,6 +14,14 @@
 <head>
 	<meta charset="<?php bloginfo('charset'); ?>">
 	<meta name="viewport" content="width=device-width, initial-scale=1.0">
+	<!-- CLS Prevention: Hide navbar-collapse before Bootstrap loads -->
+	<style id="cls-navbar-fix">
+	@media (max-width: 991.98px) {
+		.navbar-collapse:not(.show) {
+			display: none !important;
+		}
+	}
+	</style>
 	<?php wp_head(); ?>
 </head>
 
