Change mobile menu width to use percentage (#950)

Co-authored-by: automatic-pr-updater[bot] <217796550+automatic-pr-updater[bot]@users.noreply.github.com>

Author: flaberpengu

css/main.scss

@@ -367,7 +367,7 @@ header {
     position: fixed;
     top: 0;
     left: 0;
-    width: 100vw;
+    width: 100%;
     height: 100vh;
     opacity: 0;
     display: flex;