Microsoft Fluent Design System: The upcoming Windows 10 UI, previously codenamed “Project Neon,” now has an official name. At yesterday’s Build 2017, Microsoft officially unveiled it and released an updated SDK for Universal App developers that supports new APIs. The new APIs released for a better user experience are called “Microsoft Fluent Design System.”.
The Microsoft Fluent Design System is set to implement applications that use elements of the Microsoft Fluent Design System starting with the Windows 10 Fall Creators Update, which is expected to be released in September 2017. 
Some apps in recent builds of the Windows Insider program are already using parts of the UI with the new design guidelines.
The key elements that will make up Microsoft Fluent Design will be the following:
Material: A graphic solution that will mimic the feel of the materials from which the things around us are made.
Motion: A set of animations that will give an idea of how new UI elements can interact, such as an application menu that opens or draws the user's attention with controls and flyouts that will appear on the screen.
Light: It will highlight important buttons and features to attract the user's attention.
Depth: Animated images will create an impression of opening up the next level or another layer of data.
To understand the above ideas that the Microsoft Fluent Design System will be based on, watch the video below:
The company has even created a new website, https://fluent.microsoft.com/, which you can visit for more information.
If you are an app developer, you may want to get the updated SDK from the Windows Insider.
