diff --git a/components/header.js b/components/header.js
index 1028520..16e0add 100644
--- a/components/header.js
+++ b/components/header.js
@@ -120,9 +120,9 @@ export class Header extends HTMLElement {
       div.menu {
         position: fixed;
         top: 0;
-        left: -90vw;
+        left: max(-90vw, -480px);
         height: 100vh;
-        width: 90vw;
+        width: min(90vw, 480px);
         background-color: #fff;
         transition: left .25s ease-in-out;
       }