Typically, adding a sticky (or fixed) header to your website is a safe play for larger screens (desktops) because there is more room. Adding a sticky header on mobile devices with smaller viewports (especially phones) requires a little more finesse. You don’t want that sticky header taking up too much of the viewport. I mean, there’s no point in boosting the navigation experience with a sticky header if you can’t see the pages you visit. For this reason, sometimes it is easier to add a sticky header specifically designed for mobile.