Add css-cascade-4.vim

See also: http://www.w3.org/TR/2015/WD-css-cascade-4-20150908/

Author: hail2u

after/syntax/css/css-cascade-3.vim

@@ -1,3 +1,2 @@
-" TODO: create cssCommonProp
 syn keyword cssFontProp all
 syn keyword cssCommonAttr contained initial unset

after/syntax/css/css-cascade-4.vim

@@ -0,0 +1,2 @@
+syn keyword cssCommonAttr contained revert
+syn region cssURL contained matchgroup=cssFunctionName start="\<supports\s*(" end=")" oneline keepend

after/syntax/html.vim

@@ -23,6 +23,7 @@ syn include @htmlCss syntax/css/css3-transitions.vim
 syn include @htmlCss syntax/css/css3-ui.vim
 syn include @htmlCss syntax/css/css-align-3.vim
 syn include @htmlCss syntax/css/css-cascade-3.vim
+syn include @htmlCss syntax/css/css-cascade-4.vim
 syn include @htmlCss syntax/css/css-counter-styles-3.vim
 syn include @htmlCss syntax/css/css-display-3.vim
 syn include @htmlCss syntax/css/css-flexbox-1.vim

test/test.css

@@ -61,11 +61,16 @@
   box-decoration-break: auto;
 }
 
-.cascade {
+.cascade-3 {
   all: initial;
   display: unset;
 }
 
+@import "test.css" supports(display: auto);
+.cascade-4 {
+  display: revert;
+}
+
 .colors {
   opacity: rgba(0, 0, 0, 1);
   display: hsla(0, 0, 0, 1);

test/test.html

@@ -76,12 +76,18 @@
 }
 </style>
 <style>
-.cascade {
+.cascade-3 {
   all: initial;
   display: unset;
 }
 </style>
 <style>
+@import "test.css" supports(display: auto);
+.cascade-4 {
+  display: revert;
+}
+</style>
+<style>
 .colors {
   opacity: rgba(0, 0, 0, 1);
   display: hsla(0, 0, 0, 1);