diff --git a/after/syntax/css/anchor-position-1.vim b/after/syntax/css/anchor-position-1.vim
index 7780093..a91124d 100644
--- a/after/syntax/css/anchor-position-1.vim
+++ b/after/syntax/css/anchor-position-1.vim
@@ -1,4 +1,4 @@
 syn keyword cssFontProp contained anchor-name anchor-scope position-area position-anchor position-try position-try-fallbacks position-try-order position-visibility
-syn keyword cssFontAttr contained span-left span-right span-x-start span-x-end self-x-start self-x-end span-self-x-start span-self-x-end span-all span-top span-bottom span-y-start span-y-end self-y-start self-y-end span-self-y-start span-self-y-end block-start block-end span-block-start span-block-end self-block-start self-block-end span-self-block-start span-self-block-end inline-start inline-end span-inline-start span-inline-end self-inline-start self-inline-end span-self-inline-start span-self-inline-end span-start span-end self-start self-end span-self-start span-self-end anchor-center most-width most-height most-block-size most-inline-size flip-block flip-inline flip-start
+syn keyword cssFontAttr contained span-left span-right span-x-start span-x-end self-x-start self-x-end span-self-x-start span-self-x-end span-all span-top span-bottom span-y-start span-y-end self-y-start self-y-end span-self-y-start span-self-y-end block-start block-end span-block-start span-block-end self-block-start self-block-end span-self-block-start span-self-block-end inline-start inline-end span-inline-start span-inline-end self-inline-start self-inline-end span-self-inline-start span-self-inline-end span-start span-end self-start self-end span-self-start span-self-end anchor-center most-width most-height most-block-size most-inline-size flip-x flip-y flip-block flip-inline flip-start dialog
 syn region cssFunction contained matchgroup=cssFunctionName start="\<anchor\(-size\)\=\s*(" end=")" oneline keepend
 syn match cssFontDescriptor "@position-try\>" nextgroup=cssFontDescriptorBlock skipwhite skipnl
diff --git a/test/test.css b/test/test.css
index 84886bc..a55f4a4 100644
--- a/test/test.css
+++ b/test/test.css
@@ -57,6 +57,8 @@
   display: most-height;
   display: most-block-size;
   display: most-inline-size;
+  display: flip-x;
+  display: flip-y;
   display: flip-block;
   display: flip-inline;
   display: flip-start;