Add article thumbnails (first image, max 256x256, bounded by teaser height) to post cards

theme/blog_share_theme.css

@@ -574,6 +574,34 @@ html.theme-light body.is-garden #content h1#title {
     margin-top: 1.5em;
 }
 
+/* ---------- Blog post thumbnails (Bild links, Teaser rechts) ---------- */
+.blog-post-inner {
+    display: flex;
+    gap: 16px;
+    align-items: stretch;
+}
+
+.blog-thumb-link {
+    flex: 0 0 auto;
+    width: min(256px, 35%);
+    text-decoration: none;
+}
+
+.blog-thumb {
+    display: block;
+    width: 100%;
+    height: 100%;
+    max-height: 256px;
+    object-fit: cover;
+    border-radius: 8px;
+    border: 1px solid var(--background-highlight);
+}
+
+.blog-post-body {
+    flex: 1;
+    min-width: 0;
+}
+
 .blog-post-title {
     margin: 0 0 0.25em;
 }