Firefox 146 adds CSS @custom-media at-rule behind flag (#28438)

* feat(css): Add browser compatibility data for the CSS `@custom-media` at-rule

* Update css/at-rules/custom-media.json

Co-authored-by: Claas Augner <[email protected]>

---------

Co-authored-by: Claas Augner <[email protected]>

Author: ramiy

css/at-rules/custom-media.json

@@ -0,0 +1,47 @@
+{
+  "css": {
+    "at-rules": {
+      "custom-media": {
+        "__compat": {
+          "description": "`@custom-media`",
+          "spec_url": "https://drafts.csswg.org/mediaqueries-5/#at-ruledef-custom-media",
+          "support": {
+            "chrome": {
+              "version_added": false,
+              "impl_url": "https://crbug.com/40781325"
+            },
+            "chrome_android": "mirror",
+            "edge": "mirror",
+            "firefox": {
+              "version_added": "146",
+              "flags": [
+                {
+                  "type": "preference",
+                  "name": "layout.css.custom-media.enabled",
+                  "value_to_set": "true"
+                }
+              ]
+            },
+            "firefox_android": "mirror",
+            "oculus": "mirror",
+            "opera": "mirror",
+            "opera_android": "mirror",
+            "safari": {
+              "version_added": false,
+              "impl_url": "https://webkit.org/b/233820"
+            },
+            "safari_ios": "mirror",
+            "samsunginternet_android": "mirror",
+            "webview_android": "mirror",
+            "webview_ios": "mirror"
+          },
+          "status": {
+            "experimental": true,
+            "standard_track": true,
+            "deprecated": false
+          }
+        }
+      }
+    }
+  }
+}