On Android 5.*, the pull-down "notification drawer" is almost white, and color of action icons is defined (forced, even) by the system.
On Android 4.*, the pull-down "notification drawer" is dark, and the "grey, but not white" icons looks nice, I think.
The drawer has no transparency on either 4.* or 5.*.
I think you must be running a custom ROM or some sort of customization app that lets you make the "notification drawer" transparent?
Or maybe stock ROM, but the manufacturer decided to "make it like dem iPhonez"?