(defcomp
  ()
  (div
    (~tw :tokens "space-y-3")
    (button
      :sx-post "/sx/(geography.(hypermedia.(reference.(api.echo-vals))))"
      :sx-vals "{\"source\": \"demo\", \"page\": \"3\"}"
      :sx-target "#ref-vals-result"
      :sx-swap "innerHTML"
      (~tw :tokens "px-4 py-2 bg-violet-600 text-white rounded text-sm hover:bg-violet-700")
      "Send with extra values")
    (div
      :id "ref-vals-result"
      (~tw :tokens "p-3 rounded bg-stone-100 text-stone-400 text-sm")
      "Click to see echoed values.")))