A notification bar can be absolutely positioned at the top of the page by adding the class mzp-is-sticky. It will overlap and cover other content on the page so sticky notifications should usually include a button to dismiss it (the button in this example isn’t functional, it’s just for demonstration).

<aside class="mzp-c-notification-bar mzp-is-sticky">
    <button class="mzp-c-notification-bar-button" type="button">Close notification</button>
    <p>This floating bar will stick to the top of the window as you scroll.</p>
</aside>

<div class="mzp-l-content mzp-t-content-sm">
    <h1 class="mzp-u-title-sm">This is just some filler content so you have something to scroll</h1>

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</div>