Support css3-conditional properly

after/syntax/css/css3-conditional.vim

@@ -1 +1 @@
-syn region cssInclude start=/@supports\>/ end=/\ze{/ skipwhite skipnl contains=cssMediaType,cssMediaKeyword nextgroup=cssMediaBlock
+syn region cssInclude start=/@supports\>/ end=/\ze{/ skipwhite skipnl contains=css.*Prop,css.*Attr,cssValueInteger,cssValueLength,cssMediaKeyword,cssVendor,cssIncludeKeyword,cssComment nextgroup=cssMediaBlock

after/syntax/html.vim

@@ -7,7 +7,7 @@ syn include @htmlCss syntax/css/css3-box.vim
 syn include @htmlCss syntax/css/css3-break.vim
 syn include @htmlCss syntax/css/css3-cascade.vim
 syn include @htmlCss syntax/css/css3-colors.vim
-" syn include @htmlCss syntax/css/css3-conditional.vim
+syn include @htmlCss syntax/css/css3-conditional.vim
 syn include @htmlCss syntax/css/css3-content.vim
 syn include @htmlCss syntax/css/css3-exclusions.vim
 syn include @htmlCss syntax/css/css3-fonts.vim

test/test.css

@@ -71,6 +71,14 @@
   display: currentColor;
 }
 
+@supports (display: auto) or
+  (display: auto) not
+  (display: auto) {
+  .conditional {
+    display: auto;
+  }
+}
+
 .compositing {
   mix-blend-mode: multiply;
   isolation: screen;
@@ -453,14 +461,6 @@
   display: reduced;
 }
 
-@supports (display: auto) or
-  (display: auto) not
-  (display: auto) {
-    .supports {
-      display: auto;
-    }
-}
-
 .text {
   hyphens: manual;
   line-break: loose;

test/test.html

@@ -81,6 +81,14 @@
         display: currentColor;
       }
 
+      @supports (display: auto) or
+        (display: auto) not
+        (display: auto) {
+        .conditional {
+          display: auto;
+        }
+      }
+
       .compositing {
         mix-blend-mode: multiply;
         isolation: screen;
@@ -462,14 +470,6 @@
         display: reduced;
       }
 
-      @supports (display: auto) or
-        (display: auto) not
-        (display: auto) {
-        .supports {
-          display: auto;
-        }
-      }
-
       .text {
         hyphens: manual;
         line-break: loose;