Multiple Countdown Timer

This is a countdown timer which can save and invoke multiple timers.
Features:
1. You can operate multiple timers from the first screen
2. Divide timers into groups and operate all timers in the group at the same time
3. Start timers with quick action
4. Pause timers individually
5. Work timers in background
6. Dark Mode
7. Can turn off display by proximity sensor
8. Can prevent Auto-Lock while this app in foreground
9. Compatible with Apple Watch
10. Supports multiple windows on iPad