Close floating dropdowns when clicking outside them

layouts/partials/hooks/body-end.html

@@ -0,0 +1,40 @@
+{{- /* Overrides themes/docsy/layouts/partials/hooks/body-end.html, called at the end
+       of the theme's scripts.html — which every one of our baseof templates loads.
+       The theme's own body-end only carries the Algolia docsearch placeholder, kept
+       verbatim below so overriding it loses nothing. */ -}}
+{{ with .Site.Params.algolia_docsearch }}
+<!-- scripts for algolia docsearch -->
+{{ end }}
+
+{{- /* Dismiss floating <details> dropdowns.
+
+       A native <details> stays open until its own summary is clicked again, so
+       clicking anywhere else left the panel hanging over the page. Close them on an
+       outside click and on Escape, and let opening one close the others so only a
+       single panel is ever up.
+
+       Scoped to the floating dropdowns by class. .dl-archived is deliberately not in
+       the list: it is an inline accordion rather than a floating panel, and should
+       stay where the reader put it. */ -}}
+<script>
+  (function () {
+    var SEL = 'details.docs-ver, details.dl-more, details.topic-filter';
+
+    function closeAll(except) {
+      document.querySelectorAll(SEL).forEach(function (d) {
+        if (d !== except && d.open) { d.open = false; }
+      });
+    }
+
+    // Click: a click inside a dropdown keeps that one open and closes the rest;
+    // a click anywhere else closes all of them.
+    document.addEventListener('click', function (e) {
+      var target = e.target instanceof Element ? e.target.closest(SEL) : null;
+      closeAll(target);
+    });
+
+    document.addEventListener('keydown', function (e) {
+      if (e.key === 'Escape' || e.key === 'Esc') { closeAll(null); }
+    });
+  })();
+</script>