Pretty neat.
I think I found a small UI glitch: If I search and then click the browser back button when I'm on the results page, the search button on the home page shows the spinning icon.
Turns out the page was ending up in bfcache (https://web.dev/articles/bfcache), which in turn led to the button's loading state being preserved when clicking back. Listening to the `pageshow` event enables one to handle that somewhat gracefully.