fix(accordion): place children inside content div and add group wrapper

Children were appended to the outer <details> element instead of inside
the .accordion-content div, causing text to render outside the accordion
box. Also adds .accordion-group wrapper to eliminate parent gap between
stacked items, and styles content with smaller font and muted color.

dev/squint/src/dev/squint.cljs

@@ -85,9 +85,10 @@
 ;; ── Accordion ───────────────────────────────────────────────────────
 (defn accordion-demo []
   (section "Accordion"
-    (accordion/accordion {:title "What is this framework?"} "A cross-target component library.")
-    (accordion/accordion {:title "How do I use it?" :open true} "Just require the namespace and call functions.")
-    (accordion/accordion {:title "Is it accessible?"} "Yes, follows ARIA best practices.")))
+    [:div {:class "accordion-group"}
+     (accordion/accordion {:title "What is this framework?"} "A cross-target component library.")
+     (accordion/accordion {:title "How do I use it?" :open true} "Just require the namespace and call functions.")
+     (accordion/accordion {:title "Is it accessible?"} "Yes, follows ARIA best practices.")]))
 
 ;; ── Table ───────────────────────────────────────────────────────────
 (defn table-demo []