diff --git a/views/header.ejs b/views/header.ejs
index f51502d..a0c6606 100644
--- a/views/header.ejs
+++ b/views/header.ejs
@@ -10,7 +10,7 @@
     <link href="/mathjax.css" rel="stylesheet">
     <link href="/libs/KaTeX/katex.min.css" rel="stylesheet">
     <link href="/libs/morris.js/morris.css" rel="stylesheet">
-    <link href="/style.css" rel="stylesheet">
+    <link href="/style.css?20170706" rel="stylesheet">
     <script src="/libs/jquery/jquery.min.js"></script>
 </head>
 <body>
