Add @custom-media support

Author: MoOx

index.js

@@ -382,6 +382,28 @@ module.exports = function(css, options){
     });
   }
 
+
+  /**
+  * Parse custom-media.
+  */
+
+  function atcustommedia() {
+    var pos = position();
+    var m = match(/^@([-\w]+)?custom-media (--[^\s]+) *([^{]+);/);
+    if (!m) return;
+
+    var vendor = trim(m[1]);
+    var name = trim(m[2]);
+    var list = trim(m[3]);
+
+    return pos({
+      type: 'custom-media',
+      vendor: vendor,
+      name: name,
+      media: list
+    });
+  }
+
   /**
    * Parse paged media.
    */
@@ -509,6 +531,7 @@ module.exports = function(css, options){
 
     return atkeyframes()
       || atmedia()
+      || atcustommedia()
       || atsupports()
       || atimport()
       || atcharset()

test/cases/custom-media.css

@@ -0,0 +1 @@
+@custom-media --narrow-window (max-width: 30em);

test/cases/custom-media.json

@@ -0,0 +1,24 @@
+{
+  "type": "stylesheet",
+  "stylesheet": {
+    "rules": [
+      {
+        "type": "custom-media",
+        "vendor": "",
+        "name": "--narrow-window",
+        "media": "(max-width: 30em)",
+        "position": {
+          "start": {
+            "line": 1,
+            "column": 1
+          },
+          "end": {
+            "line": 1,
+            "column": 49
+          },
+          "source": "custom-media.css"
+        }
+      }
+    ]
+  }
+}