At its online-only WWDC event today, Apple took the wraps off its new wearable OS, watchOS 7. It brings sleep tracking to Apple smartwatches, with charts about weekly sleep trends and all that. Wind Down mode lets you make a customized pre-bedtime routine across your Apple Watch and iPhone, with specific scenes in the Home app, playback of soothing soundscapes, or using your favorite meditation app. In Sleep Mode, Apple Watch automatically activates the Do Not Disturb and darkens the screen overnight. To help you wake up, there's a silent haptic alarm or gentle sounds to pick...