IOS 13看起来与IOS 12大体相同，但有一个主要例外：新的全系统黑暗模式选项这是我们多年来在iOS设备上使用的标准光模式的另一种选择。
黑暗模式改变了整个操作系统的外观，使从壁纸到内置的苹果应用程序的所有东西都变暗了。苹果公司设计了特殊的黑暗模式优化壁纸，当你在黑暗模式和光明模式之间切换时，壁纸会从光变成黑暗，并且有一个黑暗模式API，所以开发者也将能够让第三方应用程序兼容。
你可以在“设置”应用程序中打开“黑暗模式”，还有一个选项可以根据您的本地时间来调度黑暗模式，以便根据自定义的时间表或在日出/日落时打开或关闭。
要快速打开或关闭黑暗模式，有一个控制中心按钮可以激活它，如果你没有打开预定的功能的话，很适合电影院或睡觉时间。
iOS 13的黑暗模式一些节省电池的功能在OLED iPhone和测试中，在黑暗模式下使用的iPhoneXSMAX比使用LightMode的iPhoneXSMAX使用的电池少。
Like iOS 12, iOS 13 introduces some notable performance improvements that makes the operating system faster and smoother on iOS devices. For devices that use Face ID, the Face ID feature unlocks up to 30 percent faster.
Apps in iOS 13 launch up to twice as fast, and apps in general are smaller. Apps are 50 percent smaller in size when you first download them, and 60 percent smaller on average when updating.
Because of these improvements, Apple has removed limitations on downloading apps over cellular, and there"s now an option to choose to allow app downloads of any size over your LTE connection.
Dark Mode
iOS 13 looks largely the same as iOS 12, but with one major exception: a new systemwide Dark Mode option that"s an alternative to the standard Light Mode that we"ve had on iOS devices for years.
Dark Mode changes the entire look of the operating system, darkening everything from the wallpaper to the built-in Apple apps. Apple designed special Dark Mode-optimized wallpapers that turn from light to dark when you switch between Dark Mode and Light Mode, and there"s a Dark Mode API, so developers are going to be able to make third-party apps compatible too.
You can turn Dark Mode on in the Settings app, and there"s also an option to schedule Dark Mode to turn on and off on a customized schedule or at sunrise/sunset based on your local time.
To quickly turn Dark Mode on or off, there"s a Control Center button that activates it, great for the movie theater or bedtime if you don"t have the scheduled feature turned on.
iOS 13"s Dark Mode appears to offer some battery saving functionality in OLED iPhones, and in testing, an iPhone XS Max used in Dark Mode used less battery than an iPhone XS Max using Light Mode.
