linear-app-launcher/RyzStudio/Windows/Forms/HorizontalSeparator.cs

using System.Drawing;
using System.Windows.Forms;

namespace RyzStudio.Windows.Forms
{
    public partial class HorizontalSeparator : System.Windows.Forms.UserControl
    {
        public HorizontalSeparator()
        {
            InitializeComponent();

            this.MaximumSize = new Size(SystemInformation.VirtualScreen.Width, 2);
        }

        protected override void OnPaintBackground(PaintEventArgs e)
        {
            base.OnPaintBackground(e);

            Graphics g = e.Graphics;
            g.FillRectangle(new SolidBrush(Color.FromArgb(213, 223, 229)), new Rectangle(this.DisplayRectangle.Left, 0, this.DisplayRectangle.Width, 1));
            g.FillRectangle(new SolidBrush(Color.FromArgb(249, 251, 253)), new Rectangle(this.DisplayRectangle.Left, 1, this.DisplayRectangle.Width, 1));
        }
    }
}