Hush - sleep timer

Hush - sleep timer is an app designed for people who like to fall asleep listening to audio media but do not want that same audio to wake them up later. Hush reduces media volume over a period of time you set, which accounts for the fact that your environment will usually grow quieter over the course of the evening.

The interface is simple and high contrast, with dark backgrounds and warm colors so it's pleasant to use when you are feeling sleepy.