When your content area is smallar then your offcanvas menu you’ll get double-rainbowed. To prevent this simply remove either body | html from the following rule in offcanvas.css
/*
* Style tweaks
* --------------------------------------------------
*/
html, body {
overflow-x: hidden; /* Prevent scroll on narrow devices */
}
so that it reads:
body {
overflow-x: hidden; /* Prevent scroll on narrow devices */
}