Centre one 42rem reading column on content, post, event and FAQ pages

Elternbeirat.Web/Features/Events/EventList.razor.css

@@ -1,14 +1,29 @@
 /* The card grid (.event-list) is shared with the home-page embed and lives in the
    global app.css; the card itself is EventCard. Only the page's own parts are here. */
 
+/* Same centred 42rem reading column as a content page (ContentPage.razor.css), so
+   every page of the site shares one column under the header. */
+h1,
+h2,
+article,
+p,
+.event-list,
+.past-events {
+    max-width: 42rem;
+    margin-inline: auto;
+}
+
+/* auto, not 0: this rule outweighs the column rule above and would otherwise pull
+   the button back to the left edge of the page. */
 .events-subscribe {
-    margin: var(--space-4) 0;
+    margin: var(--space-4) auto;
 }
 
 /* Past events: one folded-up card. Opened, a compact list grouped by year,
    deliberately quieter than the upcoming cards above. The open/close triangle is
    the shared .disclosure rule in app.css, the same as on the FAQ topics. */
 .past-events {
+    box-sizing: border-box;   /* padding inside the 42rem, flush with the text */
     margin-top: var(--space-5);
     padding: var(--space-3) var(--space-4);
     border: 1px solid var(--color-border);