Make comment box take up available space, not be tiny

agaric/sass/agaric/_layout.flow.scss

@@ -102,3 +102,10 @@
     }
   }
 }
+
+// Adding this so the comment box at the bottom isn't unnaturally small.
+// This perhaps should be more precisely targeted, or more generally.
+
+.flow.content {
+  width: 100%;
+}