Q:

Error after changing Compile using Android version

I in trying to make my first Xamarin.Android app in Visual Studio 2017.
It is necessary to use Android 7.1 (Nougat) or lower versions but default it's Android 8.1,
and when i try to change that, VS gets a lot of errors.
How i think, main error it's:

Severity  Code    Description Project File    Line    Suppression State
  Error   NU1202  Package Xamarin.Android.Support.Design 27.0.2.1 is not compatible with monoandroid71 (MonoAndroid,Version=v7.1). Package Xamarin.Android.Support.Design 27.0.2.1 supports: monoandroid81 (MonoAndroid,Version=v8.1)             

What i already tried:

Update Xamarin.Android.Support.Design in NuGet Package Manager to Latest version
Change Target android version in "Android Manifest" 
Download android SDK platforms and tools in Android SKD Manager 

Please look at this pictures: 
Error List and
Project Properties
Help me :)

A:

all you need is to change a Target android version and not a Target Framework Version, thanks Jon Douglas

