fix(comments): center empty-state illustration

assets/css/frontend/empty-state.css

@@ -1,4 +1,11 @@
 /* ========== 空状态 — 对齐 legacy empty state ========== */
+/* The media reset makes images block-level; text-align cannot center them. */
+.aksrt-null > .aksrt-null__img {
+  display: block;
+  margin-right: auto;
+  margin-left: auto;
+}
+
 .empty-state {
   text-align: center;
   padding: 60px 20px;