refa: article (#757)

Signed-off-by: bggRGjQaUbCoE <githubaccount56556@proton.me>

lib/models/dynamics/opus_detail/render_spec.dart

@@ -0,0 +1,13 @@
+class RenderSpec {
+	int? opacity;
+
+	RenderSpec({this.opacity});
+
+	factory RenderSpec.fromJson(Map<String, dynamic> json) => RenderSpec(
+				opacity: json['opacity'] as int?,
+			);
+
+	Map<String, dynamic> toJson() => {
+				'opacity': opacity,
+			};
+}