Add link-params-1.vim

https://www.w3.org/TR/2026/WD-css-link-params-1-20260714/

after/syntax/css/link-params-1.vim

@@ -0,0 +1,2 @@
+syn keyword cssFontProp contained link-parameters
+syn region cssFunction contained matchgroup=cssFunctionName start="\<param\s*(" end=")" oneline keepend

test/test.css

@@ -747,6 +747,11 @@ template {
   display: last-baseline;
 }
 
+.link-params-1 {
+  link-parameters: auto;
+  display: param(--color, green);
+}
+
 .lists-3::marker {
   marker-side: auto;
   counter-set: auto;