diff --git a/after/syntax/css/unofficials.vim b/after/syntax/css/unofficials.vim
new file mode 100644
index 0000000..1b257d8
--- /dev/null
+++ b/after/syntax/css/unofficials.vim
@@ -0,0 +1,2 @@
+syn match cssFontProp contained "\<backdrop-filter\>"
+syn region cssFunction contained matchgroup=cssFunctionName start="\<env\s*(" end=")" oneline keepend
diff --git a/test/test.css b/test/test.css
index fe1c380..a017fa6 100644
--- a/test/test.css
+++ b/test/test.css
@@ -1,3 +1,8 @@
+.unofficials {
+	backdrop-filter: auto;
+	display: env(safe-area-inset-top, 20px);
+}
+
 .align-3 {
 	place-self: auto;
 	place-content: auto;