Add css-rhythm-1.vim

See also: http://www.w3.org/TR/2017/WD-css-rhythm-1-20170302/

Author: hail2u

after/syntax/css/css-rhythm-1.vim

@@ -0,0 +1,3 @@
+syn match cssFontProp contained "\<line-height-step\>"
+syn match cssFontProp contained "\<block-step\(-\(size\|insert\|align\|round\)\)\=\>"
+syn keyword cssFontAttr contained margin up down nearest

after/syntax/html.vim

@@ -27,6 +27,7 @@ syn include @htmlCss syntax/css/css-position-3.vim
 syn include @htmlCss syntax/css/css-properties-values-api-1.vim
 syn include @htmlCss syntax/css/css-pseudo-4.vim
 syn include @htmlCss syntax/css/css-regions-1.vim
+syn include @htmlCss syntax/css/css-rhythm-1.vim
 syn include @htmlCss syntax/css/css-round-display-1.vim
 syn include @htmlCss syntax/css/css-ruby-1.vim
 syn include @htmlCss syntax/css/css-scoping-1.vim

test/test.css

@@ -461,6 +461,15 @@
   display: avoid-region;
 }
 
+.rhythm-1 {
+  line-height-step: margin;
+  block-step-size: up;
+  block-step-insert: down;
+  block-step-align: nearest;
+  block-step-round: auto;
+  block-step: auto;
+}
+
 @media (device-radius: 50%) {
   .round-display-1 {
     shape-inside: outside-shape;

test/test.html

@@ -514,6 +514,16 @@
 }
 </style>
 <style>
+.rhythm-1 {
+  line-height-step: margin;
+  block-step-size: up;
+  block-step-insert: down;
+  block-step-align: nearest;
+  block-step-round: auto;
+  block-step: auto;
+}
+</style>
+<style>
 @media (device-radius: 50%) {
   .round-display-1 {
     shape-inside: outside-shape;