diff --git a/after/syntax/css/html5.vim b/after/syntax/css/html5.vim
index e266866..6b3b3de 100644
--- a/after/syntax/css/html5.vim
+++ b/after/syntax/css/html5.vim
@@ -1 +1 @@
-syn keyword cssTagName picture rb rtc template
+syn keyword cssTagName picture rb rtc slot template
diff --git a/test/test.css b/test/test.css
index 6b72458..0736aed 100644
--- a/test/test.css
+++ b/test/test.css
@@ -818,6 +818,7 @@
 picture,
 rb,
 rtc,
+slot,
 template {
   display: auto;
 }
diff --git a/test/test.html b/test/test.html
index a9fae40..5aaf3c7 100644
--- a/test/test.html
+++ b/test/test.html
@@ -901,6 +901,7 @@
 picture,
 rb,
 rtc,
+slot,
 template {
   display: auto;
 }