Code

public CalendarSamplePage()
{
    InitializeComponent();

    calendar.MonthSettings.ShowDayOfWeek = State.Enabled;
    calendar.MonthSettings.WeekNumbersHeaderWidth = 20;
    calendar.MonthSettings.WeekHeaderAlignment = Alignment.Near;
    calendar.MonthSettings.DayOfWeekFormat = DayOfWeekFormat.Abbreviated;
    calendar.MonthSettings.Style.HeaderBrush = new LinearGradientBrush(
        Color.FromRgb(137, 176, 210), Color.FromRgb(125, 153, 180), 90);
    calendar.MonthSettings.Style.HeaderTextColor = Color.FromRgb(242, 255, 255);
    calendar.MonthSettings.Style.HeaderFont =
        calendar.MonthSettings.Style.HeaderFont.Value.WithAttributes(FontAttributes.Bold).WithSize(12);
    calendar.MonthSettings.Style.HeaderTextAlignment = MindFusion.Drawing.TextAlignment.MiddleLeft;
    calendar.MonthSettings.DaySettings.Style.BorderTopColor = Color.FromRgb(120, 140, 160);
    calendar.MonthSettings.DaySettings.Style.BorderLeftColor = Color.FromRgb(120, 140, 160);
    calendar.MonthSettings.DaySettings.Style.BorderRightColor = Color.FromRgb(120, 140, 160);
    calendar.MonthSettings.DaySettings.Style.BorderBottomColor = Color.FromRgb(120, 140, 160);
    calendar.MonthSettings.DaySettings.Style.HeaderBorderBottomColor = Color.FromRgb(120, 140, 160);
    calendar.MonthSettings.DaySettings.Style.HeaderBorderBottomWidth = 1;
    calendar.MonthSettings.DaySettings.Margin = 0;
    calendar.MonthSettings.DaySpacing = 0;
    calendar.MonthSettings.ContentsMargin = 0;
    calendar.MonthSettings.DaySpacing = 0;
    var brush = new LinearGradientBrush(Colors.Empty, Colors.Empty, 90);
    brush.Positions = new[] { 0, 0.5, 0.5, 1 };
    brush.Colors = new[] { Color.FromRgb(220, 235, 248), Color.FromRgb(213, 229, 244),
        Color.FromRgb(199, 216, 233), Color.FromRgb(199, 221, 240) };
    calendar.MonthSettings.DaySettings.Style.HeaderBrush = brush;
    calendar.MonthSettings.DaySettings.Style.HeaderTextColor = Color.Black;
    calendar.MonthSettings.DaySettings.Style.HeaderFont =
        calendar.MonthSettings.DaySettings.Style.HeaderFont.Value.WithAttributes(FontAttributes.Bold);
    calendar.MonthSettings.DaySettings.Style.HeaderTextAlignment = MindFusion.Drawing.TextAlignment.MiddleLeft;

    calendar.Selection.SelectedElementsStyle.Brush = new SolidBrush(Color.FromRgb(164, 194, 224));
    calendar.Selection.SelectedElementsStyle.HeaderBrush = brush;

    var brush2 = new LinearGradientBrush(Colors.Empty, Colors.Empty, 0);
    brush2.Positions = new[] { 0, 0.5, 0.5, 1 };
    brush2.Colors = new[] { Color.FromRgb(220, 235, 248), Color.FromRgb(213, 229, 244),
        Color.FromRgb(199, 216, 233), Color.FromRgb(199, 221, 240) };

    calendar.CustomDraw = CustomDrawElements.MonthSubHeaderCell |
        CustomDrawElements.MonthWeekNumbersHeader | CustomDrawElements.MonthWeekNumbersHeaderCell;
    calendar.Draw += (sender, e) =>
    {
        if (e.Element == CustomDrawElements.MonthWeekNumbersHeader)
        {
            var rect = e.Bounds;
            rect.Height = calendar.MonthSettings.SubHeaderHeight;
            e.Graphics.FillRectangle(new SolidBrush(Color.FromRgb(226, 241, 255)), rect);
        }
        if (e.Element == CustomDrawElements.MonthWeekNumbersHeaderCell)
        {
            e.Graphics.FillRectangle(new SolidBrush(Color.FromRgb(226, 241, 255)), e.Bounds);

            var rect = e.Bounds;
            rect.Y += calendar.MonthSettings.DaySettings.HeaderSize;
            rect.Height -= calendar.MonthSettings.DaySettings.HeaderSize;
            e.Graphics.FillRectangle(brush2, rect);
            e.Graphics.DrawString(e.Text, e.Style.Font.Value, new SolidBrush(Color.FromRgb(130, 151, 172)), rect,
                new StringFormat { HorizontalAlignment = HorizontalAlignment.Center, VerticalAlignment = VerticalAlignment.Center });
            e.Graphics.DrawRectangle(new Pen(Color.FromRgb(120, 140, 160), 1, PenUnit.Pixel), rect);
        }
        if (e.Element == CustomDrawElements.MonthSubHeaderCell)
        {
            e.Graphics.FillRectangle(new SolidBrush(Color.FromRgb(226, 241, 255)), e.Bounds);
            e.Graphics.DrawString(e.Text, e.Style.Font.Value, new SolidBrush(Color.FromRgb(130, 151, 172)), e.Bounds,
                new StringFormat { HorizontalAlignment = HorizontalAlignment.Center, VerticalAlignment = VerticalAlignment.Center });
        }
    };
}