diff --git a/after/syntax/css/css-writing-modes-3.vim b/after/syntax/css/css-writing-modes-3.vim
index a2626e9..d8ce9e3 100644
--- a/after/syntax/css/css-writing-modes-3.vim
+++ b/after/syntax/css/css-writing-modes-3.vim
@@ -1,8 +1,7 @@
 syn match cssFontProp contained "\<writing-mode\>"
 syn match cssFontProp contained "\<text-\(orientation\|combine-upright\)\>"
 syn match cssFontProp contained "\<glyph-orientation-vertical\>"
-syn keyword cssFontAttr contained before after mixed upright plaintext
-syn match cssFontAttr contained "\<sideways\(-rl\|-lr\)\=\>"
+syn keyword cssFontAttr contained before after mixed upright plaintext sideways
 syn match cssFontAttr contained "\<isolate\(-override\)\=\>"
 syn match cssFontAttr contained "\<horizontal-tb\>"
 syn match cssFontAttr contained "\<vertical-\(rl\|lr\)\>"
diff --git a/after/syntax/css/css-writing-modes-4.vim b/after/syntax/css/css-writing-modes-4.vim
new file mode 100644
index 0000000..0dc6082
--- /dev/null
+++ b/after/syntax/css/css-writing-modes-4.vim
@@ -0,0 +1 @@
+syn match cssFontAttr contained "\<sideways-\(rl\|lr\)\>"
diff --git a/test/test.css b/test/test.css
index fea9568..188b324 100644
--- a/test/test.css
+++ b/test/test.css
@@ -889,8 +889,6 @@
   glyph-orientation-vertical: upright;
   display: plaintext;
   display: sideways;
-  display: sideways-rl;
-  display: sideways-lr;
   display: isolate;
   display: isolate-override;
   display: horizontal-tb;
@@ -898,6 +896,11 @@
   display: vertical-lr;
 }
 
+.writing-modes-4 {
+  display: sideways-rl;
+  display: sideways-lr;
+}
+
 .html5,
 picture,
 rb,