diff --git a/after/syntax/css/box-3.vim b/after/syntax/css/box-3.vim
index cc6d6fe..ff4705d 100644
--- a/after/syntax/css/box-3.vim
+++ b/after/syntax/css/box-3.vim
@@ -1,3 +1,5 @@
+syn match cssBoxProp contained "\<margin-trim\>"
+syn match cssBoxAttr contained "\<in-flow\>"
 " These will be moved to block-3
 syn match cssBoxProp contained "\<clear-after\>"
 syn match cssBoxProp contained "\<float-displace\>"
diff --git a/test/test.css b/test/test.css
index 370df85..1cf26af 100644
--- a/test/test.css
+++ b/test/test.css
@@ -43,6 +43,9 @@
 }
 
 .box-3 {
+  margin-trim: auto;
+  display: in-flow;
+  /* .block-3 */
   clear-after: auto;
   float-displace: auto;
   indent-edge-reset: auto;