add support for CSS3 Basic User Interface

after/syntax/css/css3-properties.vim

@@ -8,8 +8,4 @@ syn keyword cssColorProp contained opacity
 syn match cssTextProp contained "\<text-\(shadow\|overflow\)\>"
 syn match cssTextProp contained "\<word-wrap\>"
 
-syn match cssBoxProp contained "\<box-sizing\>"
-syn keyword cssBoxProp contained resize
-syn match cssBoxProp contained "\<nav-\(up\|right\|down\|left\)"
-
 syn match cssBoxProp contained "\<overflow-\(x\|y\)\>"

after/syntax/css/css3-ui.vim

@@ -0,0 +1,5 @@
+syn keyword cssUIProp contained appearance resize
+syn match cssUIProp contained "\<box-sizing\>"
+syn match cssUIProp contained "\<nav-\(up\|right\|down\|left\)"
+syn keyword cssUIAttr contained root horizontal vertical
+syn match cssUIAttr contained "\<\(content\|border\)-box\>"