The using static [Namespace.Type] directive allows the importing of static members of types and enumeration values. Extension methods are imported as extension methods (from just one type), not into top-level scope.

using static System.Console;
using static System.ConsoleColor;
using static System.Math;

class Program
{
    static void Main()
    {
        BackgroundColor = DarkBlue;
        WriteLine(Sqrt(2));
    }
}

Live Demo Fiddle