Workaround transparent style issues on Mac OS

src/blackgui/share/qss/stdwidget.qss

@@ -308,6 +308,7 @@ QToolBox::tab {
 }
 
 QToolBox::tab::selected {
+  color: rgba(255, 255, 0, 255);
   background-color: rgba(0, 0, 255, 128);
 }
 

src/blackgui/share/qss/swiftlauncher.qss

@@ -1,3 +1,11 @@
+/** Works around two issues on Mac OS
+      1. The launcher dialog was entirely transparent
+      2. Transparency caused the QToolBox labels to be broken
+*/
+QStackedWidget#sw_SwiftLauncher {
+  background-image: url(:/textures/icons/textures/texture-inner.jpg);
+}
+
 /** special effects for start buttons **/
 #pg_Start QToolButton {
   border: 1px solid green;