How to Create a Metro Login form using Metro Framework in C#
Step 1: Click New Project, then select Visual C# on the left, then Windows and then select Windows Forms Application. Name your project "MetroLoginApp" and then click OK
Step 2: Right click on your project select Manage NuGet Packages -> Search metro framework, dapper -> Install

If you don't see the metro framework in your toolbox, you can view How to download and install metro framework
Step 3: Design metro login form as below

Add code to change style/theme for Metro Form
public partial class Form1 : MetroFramework.Forms.MetroForm//Replace System.Windows.Forms.Form
{
public Form1()
{
InitializeComponent();
}
private void Form1_Load(object sender, EventArgs e)
{
//Init style/theme
this.StyleManager = metroStyleManager1;
metroStyleManager1.Theme = MetroFramework.MetroThemeStyle.Light;
metroStyleManager1.Style = MetroFramework.MetroColorStyle.Green;
}
}
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