GTK3,4: Correct menu shadows

src/gtk3/widgets/_window_decorations.scss

@@ -23,7 +23,8 @@ decoration {
 	}
 	.popup & {
 		border-radius: $r;
-		box-shadow: 2px 2px 2px 1px rgba(0, 0, 0, 0.1);
+		box-shadow: 0px 3px 10px -4px rgba(0, 0, 0, 0.27),
+					0px 5px 8px -4px rgba(0, 0, 0, 0.17);
 	}
 	// server-side decorations as used by mutter
 	.ssd & {
@@ -32,7 +33,8 @@ decoration {
 	.csd & {
 		border-radius: 6px;
 		&.popup {
-			box-shadow: 2px 2px 2px 1px rgba(0, 0, 0, 0.1);
+			box-shadow: 0px 3px 10px -4px rgba(0, 0, 0, 0.27),
+						0px 5px 8px -4px rgba(0, 0, 0, 0.17);
 		}
 		&.tooltip {
 			box-shadow: none;

src/gtk4/widgets/_window_decorations.scss

@@ -27,7 +27,8 @@ window {
 	}
 	.popup & {
 		border-radius: $r;
-		box-shadow: 2px 2px 2px 1px rgba(0, 0, 0, 0.1);
+		box-shadow: 0px 3px 10px -4px rgba(0, 0, 0, 0.27),
+					0px 5px 8px -4px rgba(0, 0, 0, 0.17);
 	}
 	// server-side decorations as used by mutter
 	.ssd & {
@@ -36,7 +37,8 @@ window {
 	.csd & {
 		border-radius: 6px;
 		&.popup {
-			box-shadow: 2px 2px 2px 1px rgba(0, 0, 0, 0.1);
+			box-shadow: 0px 3px 10px -4px rgba(0, 0, 0, 0.27),
+						0px 5px 8px -4px rgba(0, 0, 0, 0.17);
 		}
 		&.tooltip {
 			box-shadow: none;