Extract date rendering into per-feature Date components

Elternbeirat.Web/Features/Posts/PostDetail.razor.css

@@ -1,7 +1,15 @@
-.post-meta {
-    display: block;
-    color: var(--color-text-soft);   /* token, so it adapts in dark mode */
-    font-size: 0.85rem;
-    margin-top: 1.5rem;              /* space from the "all posts" link above */
-    margin-bottom: 0.25rem;         /* keep the body close below */
+/* Push the whole article body down from the "all posts" link above it. Wraps the
+   date, heading and body, so scoped CSS applies (the date sits in the PostDate
+   child component and would not be reachable on its own). The date's own look
+   comes from PostDate.razor.css. */
+.post-content {
+    margin-top: 1.5rem;
+}
+
+/* The post title is the first h2 in the content, sitting right under its date, so
+   drop the large default heading gap above it (h1..h4 carry --space-5 top margin
+   globally); date and title belong together. Scoped to :first-of-type so h2
+   subheadings inside the Markdown body keep their normal spacing. */
+.post-content h2:first-of-type {
+    margin-top: var(--space-1);
 }