Add Custom Media Queries

features/custom-media-queries.yml

@@ -0,0 +1,7 @@
+name: Custom media queries
+description: Named aliases for longer and more complex media queries, deffined once in a `@custom-media` rule and used as reusable variables in multiple `@media` rules.
+spec: https://www.w3.org/TR/mediaqueries-5/#at-ruledef-custom-media
+group: media-queries
+status:
+  baseline: false
+  support: {}