Add kiosk.js file with the content below to your www folder in config.
Like any other custom script, use ui-lovelace.yaml resources section to reference the kiosk.js file.
Make sure you add kiosk somewhere in your URL. You can use it in the id of your view or in the query string.
Examples:
/lovelace/0?kiosk
views:
- title: Kiosk
icon: mdi:heart
id: kiosk_alarmIf this is your first file in www make sure you restart Home Assistant.

Thanks, Justin. I'm using the code in the box at the top of this article, modified only to change style.display from "none" to "block" in the header statement. I've tried a couple of variants. My intent is what you see in the second picture I posted, which is the full header without a space to the left of it. (I'd be happy with the view tabs only, and not the rest of the header; but the problem with hiding the header is that by default it also hides the view tabs, and I need the view tabs, as shown above.)