diff --git a/lib/rdoc/generator/template/darkfish/js/darkfish.js b/lib/rdoc/generator/template/darkfish/js/darkfish.js
index aeb8526344..ed3893379d 100644
--- a/lib/rdoc/generator/template/darkfish/js/darkfish.js
+++ b/lib/rdoc/generator/template/darkfish/js/darkfish.js
@@ -99,7 +99,7 @@ function hookSidebar() {
     navigationToggle.ariaExpanded = navigationToggle.ariaExpanded !== 'true';
   });
 
-  var isSmallViewport = window.matchMedia("(max-width: 1024px)").matches;
+  var isSmallViewport = window.matchMedia("(max-width: 1023px)").matches;
   if (isSmallViewport) {
     navigation.hidden = true;
     navigationToggle.ariaExpanded = false;