diff --git a/src/ci_orchestrator/web/static/app.css b/src/ci_orchestrator/web/static/app.css
index edee0d1..d08f995 100644
--- a/src/ci_orchestrator/web/static/app.css
+++ b/src/ci_orchestrator/web/static/app.css
@@ -268,11 +268,14 @@ dd code, dd .mono { overflow-wrap: anywhere; }
 .maintenance-op-info { flex: 1 1 320px; min-width: 0; }
 .maintenance-op h3 { font-size: 0.95rem; margin: 0 0 0.15rem; }
 .maintenance-op .field-hint { margin: 0; }
-.maintenance-op form { flex: none; }
-/* The max-age control sits on its own row above the action buttons, so it
- * reads as a general max-age parameter of the operation (not part of a
- * button). */
-.op-field { display: flex; align-items: center; gap: 0.5rem; margin-bottom: 0.5rem; }
+/* The form inherits the global block-``form`` flex row, so its max-age field
+ * and its button row are laid out as siblings on one line (wrapping only when
+ * the card is narrow). Both the global ``margin-top`` and any bottom margin on
+ * the field must be zeroed here: flex centring uses each item's *margin* box,
+ * so a 0.5rem bottom margin on the field lifts the number input (and its
+ * stepper arrows) half that above the buttons' centre line. */
+.maintenance-op form { flex: none; margin-top: 0; }
+.op-field { display: flex; align-items: center; gap: 0.5rem; }
 .op-field label { font-size: 0.85rem; color: var(--text-dim); white-space: nowrap; }
 .op-field input { width: 6rem; }
 /* A row of buttons (e.g. Purge / Empty all) that wraps on narrow cards. */