diff --git a/index.html b/index.html
index 342f617..abfebc3 100644
--- a/index.html
+++ b/index.html
@@ -4,11 +4,13 @@
 <head>
   <meta charset="utf-8">
   <meta name="viewport" content="width=device-width, initial-scale=1" />
+  <meta http-equiv="Content-Security-Policy"
+    content="default-src 'none'; style-src 'self' 'sha256-A9xtS8HrcEvVhzeEYgYutGzORfRrCU33XeWzOjB7C90='; font-src 'self'; script-src 'self' 'sha256-1B510eYYZON4TAfJqjedCNN5U/G8U6LtuiFCIay2bVg='; worker-src 'self';">
   <title>Watterblock</title>
 
   <link rel="stylesheet" href="/vendored/normalize-8.0.1.css">
   <link rel="stylesheet" href="/style.css">
-  <link rel="stylesheet" href="/vendored/material-icons.css" />
+  <link rel="stylesheet" href="/vendored/material-icons.css">
   <noscript>
     <style>
       ._yesscript {
@@ -56,4 +58,4 @@
   </noscript>
 </body>
 
-</html>
\ No newline at end of file
+</html>
