The header and footer took more room than the rows they frame,
so they close to 2xs, and the sides stay just the same.

Assisted-by: Claude Opus 5 via Claude Code

diff --git a/public/admin.css b/public/admin.css
index 7bdc604..251f92b 100644
--- a/public/admin.css
+++ b/public/admin.css
@@ -615,6 +615,15 @@ a.tag {
   text-decoration: none;
 }
 
+/* A dialog's title and action bars close to the smallest step the
+   record's rows use, a line and its buttons being all either holds;
+   Gloss's own spend more of a short dialog on chrome than on content.
+   The sides keep Gloss's step, so the bars stay aligned with the body. */
+dialog > header,
+dialog > footer {
+  padding-block: var(--gl-space-2xs);
+}
+
 /* The stored card in its own collapsed card under the record — the
    column's gap spaces the two, so no margin here. <details> is native,
    keeping the admin UI script-free; the summary rides the label