diff --git a/OneMore/Helpers/Office/Office.cs b/OneMore/Helpers/Office/Office.cs
index ae1c996008..5e1536f4b4 100644
--- a/OneMore/Helpers/Office/Office.cs
+++ b/OneMore/Helpers/Office/Office.cs
@@ -166,8 +166,11 @@ private static bool DarkModeLightsOn()
 		/// <summary>
 		/// Determines if Windows is set to dark mode
 		/// </summary>
-		/// <returns></returns>
-		private static bool SystemDefaultDarkMode()
+		/// <returns>True if the system default is dark mode</returns>
+		/// <remarks>
+		/// Declared as public so it can be used by OneMoreCalendar
+		/// </remarks>
+		public static bool SystemDefaultDarkMode()
 		{
 			using var key = Registry.CurrentUser.OpenSubKey(
 				@"SOFTWARE\Microsoft\Windows\CurrentVersion\Themes\Personalize");
diff --git a/OneMoreCalendar/AboutDialog.Designer.cs b/OneMoreCalendar/AboutDialog.Designer.cs
index e24244af58..1914dc6bd2 100644
--- a/OneMoreCalendar/AboutDialog.Designer.cs
+++ b/OneMoreCalendar/AboutDialog.Designer.cs
@@ -34,10 +34,10 @@ private void InitializeComponent ()
 			this.copyLabel = new System.Windows.Forms.Label();
 			this.okButton = new OneMoreCalendar.MoreButton();
 			this.pleaseLabel = new System.Windows.Forms.Label();
-			this.pictureBox1 = new System.Windows.Forms.PictureBox();
+			this.logoBox = new System.Windows.Forms.PictureBox();
 			this.sponsorButton = new River.OneMoreAddIn.UI.MoreButton();
 			this.homeLink = new River.OneMoreAddIn.UI.MoreLinkLabel();
-			((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).BeginInit();
+			((System.ComponentModel.ISupportInitialize)(this.logoBox)).BeginInit();
 			this.SuspendLayout();
 			// 
 			// titleLabel
@@ -96,15 +96,15 @@ private void InitializeComponent ()
 			this.pleaseLabel.TabIndex = 14;
 			this.pleaseLabel.Text = "Please support future development of OneMore";
 			// 
-			// pictureBox1
+			// logoBox
 			// 
-			this.pictureBox1.Image = ((System.Drawing.Image)(resources.GetObject("pictureBox1.Image")));
-			this.pictureBox1.Location = new System.Drawing.Point(12, 12);
-			this.pictureBox1.Name = "pictureBox1";
-			this.pictureBox1.Size = new System.Drawing.Size(124, 125);
-			this.pictureBox1.SizeMode = System.Windows.Forms.PictureBoxSizeMode.StretchImage;
-			this.pictureBox1.TabIndex = 0;
-			this.pictureBox1.TabStop = false;
+			this.logoBox.Image = ((System.Drawing.Image)(resources.GetObject("pictureBox1.Image")));
+			this.logoBox.Location = new System.Drawing.Point(12, 12);
+			this.logoBox.Name = "pictureBox1";
+			this.logoBox.Size = new System.Drawing.Size(124, 125);
+			this.logoBox.SizeMode = System.Windows.Forms.PictureBoxSizeMode.StretchImage;
+			this.logoBox.TabIndex = 0;
+			this.logoBox.TabStop = false;
 			// 
 			// sponsorButton
 			// 
@@ -154,7 +154,7 @@ private void InitializeComponent ()
 			this.Controls.Add(this.copyLabel);
 			this.Controls.Add(this.versionLabel);
 			this.Controls.Add(this.titleLabel);
-			this.Controls.Add(this.pictureBox1);
+			this.Controls.Add(this.logoBox);
 			this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedDialog;
 			this.MaximizeBox = false;
 			this.MinimizeBox = false;
@@ -163,7 +163,7 @@ private void InitializeComponent ()
 			this.ShowInTaskbar = false;
 			this.StartPosition = System.Windows.Forms.FormStartPosition.CenterParent;
 			this.Text = "OneMore Calendar";
-			((System.ComponentModel.ISupportInitialize)(this.pictureBox1)).EndInit();
+			((System.ComponentModel.ISupportInitialize)(this.logoBox)).EndInit();
 			this.ResumeLayout(false);
 			this.PerformLayout();
 
@@ -171,11 +171,11 @@ private void InitializeComponent ()
 
 		#endregion
 
-		private System.Windows.Forms.PictureBox pictureBox1;
+		private System.Windows.Forms.PictureBox logoBox;
 		private System.Windows.Forms.Label titleLabel;
 		private System.Windows.Forms.Label versionLabel;
 		private System.Windows.Forms.Label copyLabel;
-		private MoreButton okButton;
+		private OneMoreCalendar.MoreButton okButton;
 		private River.OneMoreAddIn.UI.MoreLinkLabel homeLink;
 		private River.OneMoreAddIn.UI.MoreButton sponsorButton;
 		private System.Windows.Forms.Label pleaseLabel;
diff --git a/OneMoreCalendar/AboutDialog.cs b/OneMoreCalendar/AboutDialog.cs
index d0adb1bfb9..dd064dfccd 100644
--- a/OneMoreCalendar/AboutDialog.cs
+++ b/OneMoreCalendar/AboutDialog.cs
@@ -5,11 +5,10 @@
 namespace OneMoreCalendar
 {
 	using System;
-	using System.Drawing;
 	using System.Windows.Forms;
 
 
-	internal partial class AboutDialog : Form
+	internal partial class AboutDialog : ThemedForm
 	{
 
 		public AboutDialog()
@@ -19,11 +18,18 @@ public AboutDialog()
 			sponsorButton.SetHandCursor();
 
 			// TODO: beta
-			versionLabel.Text = string.Format(versionLabel.Text, AssemblyInfo.Version) + " (BETA)";
+			versionLabel.Text = string.Format(versionLabel.Text, AssemblyInfo.Version);
 			copyLabel.Text = string.Format(copyLabel.Text, DateTime.Now.Year);
 		}
 
 
+		protected override void OnLoad(EventArgs e)
+		{
+			base.OnLoad(e);
+			BackColor = Theme.BackColor;
+		}
+
+
 		private void OK(object sender, EventArgs e)
 		{
 			Close();
diff --git a/OneMoreCalendar/CalendarForm.cs b/OneMoreCalendar/CalendarForm.cs
index 487c80263e..a4d20f2a60 100644
--- a/OneMoreCalendar/CalendarForm.cs
+++ b/OneMoreCalendar/CalendarForm.cs
@@ -4,8 +4,10 @@
 
 namespace OneMoreCalendar
 {
+	using OneMoreCalendar.Properties;
 	using River.OneMoreAddIn;
 	using System;
+	using System.Drawing;
 	using System.IO;
 	using System.Threading.Tasks;
 	using System.Windows.Forms;
@@ -14,7 +16,7 @@ namespace OneMoreCalendar
 	/// <summary>
 	/// Main OneMoreCalendar form
 	/// </summary>
-	public partial class CalendarForm : Form
+	internal partial class CalendarForm : ThemedForm
 	{
 		private DateTime date;
 		private CalendarPages pages;
@@ -35,9 +37,6 @@ public CalendarForm()
 
 			Width = 1500; // TODO: save as settings?
 			Height = 1000;
-
-			// TODO: beta
-			Text = $"{Text} (BETA)";
 		}
 
 
@@ -72,6 +71,32 @@ protected override async void OnLoad(EventArgs e)
 		}
 
 
+		public override void OnThemeChange()
+		{
+			if (Theme.DarkMode)
+			{
+				var fromColor = ColorTranslator.FromHtml("#FF80397B");
+				todayButton.Image = Resources.today_32.MapColor(fromColor, Color.MediumOrchid);
+				monthButton.Image = Resources.month_32.MapColor(fromColor, Color.MediumOrchid);
+				dayButton.Image = Resources.day_32.MapColor(fromColor, Color.MediumOrchid);
+				settingsButton.Image = Resources.settings_32.MapColor(fromColor, Color.MediumOrchid);
+			}
+			else
+			{
+				todayButton.Image = Resources.settings_32;
+				monthButton.Image = Resources.month_32;
+				dayButton.Image = Resources.day_32;
+				settingsButton.Image = Resources.settings_32;
+			}
+
+			nextButton.PreferredFore = Theme.LinkColor;
+			nextButton.PreferredBack = Theme.BackColor;
+			prevButton.PreferredFore = Theme.LinkColor;
+			prevButton.PreferredBack = Theme.BackColor;
+			todayButton.PreferredBack = Theme.BackColor;
+		}
+
+
 		private async Task SetMonth(int delta)
 		{
 			if (delta < 1000)
@@ -166,6 +191,8 @@ await settings.GetNotebookIDs(),
 				settings.Created, settings.Modified, settings.Deleted);
 
 			detailView.SetRange(date, endDate, pages);
+			detailView.OnThemeChange();
+
 			contentPanel.Controls.Add(detailView);
 		}
 
@@ -378,6 +405,7 @@ private async void ClosingSettings(object sender, FormClosingEventArgs e)
 
 			if (settingsForm.DialogResult == DialogResult.OK)
 			{
+				Theme.InitializeTheme(this);
 				await SetMonth(date.Year);
 			}
 		}
diff --git a/OneMoreCalendar/DetailView.cs b/OneMoreCalendar/DetailView.cs
index a51e690e40..a1d39996eb 100644
--- a/OneMoreCalendar/DetailView.cs
+++ b/OneMoreCalendar/DetailView.cs
@@ -13,7 +13,7 @@ namespace OneMoreCalendar
 	using System.Windows.Forms;
 
 
-	internal partial class DetailView : UserControl, ICalendarView
+	internal partial class DetailView : ThemedUserControl, ICalendarView
 	{
 		private sealed class DayItem
 		{
@@ -52,6 +52,12 @@ public DetailView()
 		}
 
 
+		public override void OnThemeChange()
+		{
+			BackColor = Theme.BackColor;
+		}
+
+
 		public event CalendarDayHandler ClickedDay;
 		public event CalendarHoverHandler HoverPage;
 		public event CalendarPageHandler ClickedPage;
@@ -60,6 +66,7 @@ public DetailView()
 
 		public void SetRange(DateTime startDate, DateTime endDate, CalendarPages pages)
 		{
+			SuspendLayout();
 			listbox.Items.Clear();
 
 			var date = startDate;
@@ -89,27 +96,26 @@ public void SetRange(DateTime startDate, DateTime endDate, CalendarPages pages)
 			}
 
 			Invalidate();
+			ResumeLayout();
 		}
 
 
 		private void HeaderPanelPaint(object sender, PaintEventArgs e)
 		{
-			using (var font = new Font("Segoe UI Light", 10.0f, FontStyle.Regular))
-			{
-				headerPanel.Height = font.Height + VPadding;
-				var y = (headerPanel.Height - font.Height) / 2;
+			using var font = new Font("Segoe UI Light", 10.0f, FontStyle.Regular);
+			headerPanel.Height = font.Height + VPadding;
+			var y = (headerPanel.Height - font.Height) / 2;
 
-				var size = e.Graphics.MeasureString("DATE", font);
-				e.Graphics.DrawString("DATE", font, Brushes.SlateGray,
-					(HeadWidth - size.Width) / 2, y);
+			var size = e.Graphics.MeasureString("DATE", font);
+			var width = e.ClipRectangle.Width - SystemInformation.VerticalScrollBarWidth;
 
-				var width = e.ClipRectangle.Width - SystemInformation.VerticalScrollBarWidth;
+			using var brush = new SolidBrush(Theme.MonthDayFore);
 
-				e.Graphics.DrawString("SECTION", font, Brushes.SlateGray, HeadWidth + 20, y);
-				e.Graphics.DrawString("PAGE", font, Brushes.SlateGray, HeadWidth + PathWidth + 40, y);
-				e.Graphics.DrawString("CREATED", font, Brushes.SlateGray, width - DateWidth * 2, y);
-				e.Graphics.DrawString("MODIFIED", font, Brushes.SlateGray, width - DateWidth, y);
-			}
+			e.Graphics.DrawString("DATE", font, brush, (HeadWidth - size.Width) / 2, y);
+			e.Graphics.DrawString("SECTION", font, brush, HeadWidth + 20, y);
+			e.Graphics.DrawString("PAGE", font, brush, HeadWidth + PathWidth + 40, y);
+			e.Graphics.DrawString("CREATED", font, brush, width - DateWidth * 2, y);
+			e.Graphics.DrawString("MODIFIED", font, brush, width - DateWidth, y);
 		}
 
 
@@ -138,9 +144,11 @@ private void ListBoxDrawItem(object sender, DrawItemEventArgs e)
 				return;
 			}
 
-			e.Graphics.FillRectangle(e.Index % 2 == 1 ? AppColors.RowBrush : Brushes.White, e.Bounds);
+			using var fill = new SolidBrush(e.Index % 2 == 1 ? Theme.DetailOddBack : Theme.DetailEvenBack);
+			e.Graphics.FillRectangle(fill, e.Bounds);
 
-			e.Graphics.DrawLine(Pens.LightGray, e.Bounds.Left, e.Bounds.Top, e.Bounds.Width, e.Bounds.Top);
+			using var line = new Pen(Theme.MonthGrid);
+			e.Graphics.DrawLine(line, e.Bounds.Left, e.Bounds.Top, e.Bounds.Width, e.Bounds.Top);
 			//e.Graphics.DrawLine(Pens.LightGray, HeadWidth, e.Bounds.Top, HeadWidth, e.Bounds.Bottom);
 
 			if (listbox.Items[e.Index] is DayItem day)
@@ -151,7 +159,11 @@ private void ListBoxDrawItem(object sender, DrawItemEventArgs e)
 				// header
 				var head = day.Date.ToString("ddd, MMM d");
 				var size = e.Graphics.MeasureString(head, listbox.Font);
-				e.Graphics.DrawString(head, listbox.Font, Brushes.Black,
+
+				using var fore = new SolidBrush(Theme.ForeColor);
+				using var gray = new SolidBrush(Color.Gray);
+
+				e.Graphics.DrawString(head, listbox.Font, fore,
 					(HeadWidth - size.Width) / 2,
 					e.Bounds.Top + (e.Bounds.Height - size.Height) / 2);
 
@@ -162,7 +174,7 @@ private void ListBoxDrawItem(object sender, DrawItemEventArgs e)
 					// predict width of page title
 					size = e.Graphics.MeasureString(page.Title, listbox.Font);
 
-					var color = page.IsDeleted ? Brushes.Gray : Brushes.Black;
+					var color = page.IsDeleted ? gray : fore;
 
 					// section
 					e.Graphics.DrawString(page.Path,
@@ -239,11 +251,14 @@ private void ListBoxMouseMove(object sender, MouseEventArgs e)
 				using (var g = listbox.CreateGraphics())
 				{
 					var index = listbox.Items.IndexOf(hotday);
-					g.FillRectangle(index % 2 == 1 ? AppColors.RowBrush : Brushes.White, hotpage.Bounds);
+					using var fill = new SolidBrush(index % 2 == 1 ? Theme.DetailOddBack : Theme.DetailEvenBack);
+					g.FillRectangle(fill, hotpage.Bounds);
+
+					using var fore = new SolidBrush(hotpage.IsDeleted ? Color.Gray : Theme.ForeColor);
 
 					g.DrawString(hotpage.Title,
 						hotpage.IsDeleted ? deletedFont : listbox.Font,
-						hotpage.IsDeleted ? Brushes.Gray : Brushes.Black,
+						fore,
 						hotpage.Bounds, format);
 				}
 
@@ -258,11 +273,13 @@ private void ListBoxMouseMove(object sender, MouseEventArgs e)
 				using (var g = listbox.CreateGraphics())
 				{
 					var index = listbox.Items.IndexOf(day);
-					g.FillRectangle(index % 2 == 1 ? AppColors.RowBrush : Brushes.White, page.Bounds);
+					using var fill = new SolidBrush(index % 2 == 1 ? Theme.DetailOddBack : Theme.DetailEvenBack);
+					g.FillRectangle(fill, page.Bounds);
 
+					using var fore = new SolidBrush(Theme.Highlight);
 					g.DrawString(page.Title,
 						page.IsDeleted ? deletedFont : hotFont,
-						Brushes.DarkOrchid, page.Bounds, format);
+						fore, page.Bounds, format);
 				}
 
 				HoverPage?.Invoke(this, new CalendarPageEventArgs(page));
diff --git a/OneMoreCalendar/MonthView.cs b/OneMoreCalendar/MonthView.cs
index aacfce86bf..e877d4ad84 100644
--- a/OneMoreCalendar/MonthView.cs
+++ b/OneMoreCalendar/MonthView.cs
@@ -13,7 +13,7 @@ namespace OneMoreCalendar
 	using System.Windows.Forms;
 
 
-	internal partial class MonthView : UserControl, ICalendarView
+	internal partial class MonthView : ThemedUserControl, ICalendarView
 	{
 		private enum Hottype { Day, Page, Up, Down }
 
@@ -208,10 +208,8 @@ private void ScrollDay(Hotspot spot)
 
 			spot.Day.ScrollOffset = offset;
 
-			using (var g = CreateGraphics())
-			{
-				PaintDay(g, spot.Day);
-			}
+			using var g = CreateGraphics();
+			PaintDay(g, spot.Day);
 		}
 
 
@@ -241,9 +239,11 @@ protected override void OnMouseMove(MouseEventArgs e)
 				{
 					using (var g = CreateGraphics())
 					{
-						g.FillRectangle(
-							hotspot.Page.Modified.Month == date.Month ? Brushes.White : Brushes.WhiteSmoke,
-							hotspot.Bounds);
+						using var brush = hotspot.Page.Modified.Month == date.Month
+							? new SolidBrush(Theme.MonthPrimary)
+							: new SolidBrush(Theme.MonthSecondary);
+
+						g.FillRectangle(brush, hotspot.Bounds);
 
 						if (hotspot.Page.IsDeleted)
 						{
@@ -253,8 +253,10 @@ protected override void OnMouseMove(MouseEventArgs e)
 						}
 						else
 						{
-							var brush = hotspot.InMonth ? Brushes.Black : Brushes.Gray;
-							g.DrawString(hotspot.Page.Title, Font, brush, hotspot.Bounds, format);
+							var titleBrush = new SolidBrush(hotspot.InMonth
+								? Theme.MonthTodayFore : Theme.MonthDayFore);
+
+							g.DrawString(hotspot.Page.Title, Font, titleBrush, hotspot.Bounds, format);
 						}
 					}
 
@@ -273,12 +275,12 @@ protected override void OnMouseMove(MouseEventArgs e)
 				{
 					using (var g = CreateGraphics())
 					{
-						var brush = spot.InMonth ? Brushes.White : Brushes.WhiteSmoke;
-						g.FillRectangle(brush, spot.Bounds);
+						using var fill = new SolidBrush(spot.InMonth ? Theme.MonthPrimary : Theme.MonthSecondary);
+						g.FillRectangle(fill, spot.Bounds);
 
+						using var fore = new SolidBrush(Theme.Highlight);
 						g.DrawString(spot.Page.Title,
-							spot.Page.IsDeleted ? deletedFont : hotFont,
-							Brushes.DarkOrchid,
+							spot.Page.IsDeleted ? deletedFont : hotFont, fore,
 							new Rectangle(spot.Bounds.X, spot.Bounds.Y, width, spot.Bounds.Height),
 							format);
 					}
@@ -294,26 +296,30 @@ protected override void OnMouseMove(MouseEventArgs e)
 
 		protected override void OnPaint(PaintEventArgs e)
 		{
+			SuspendLayout();
+
 			base.OnPaint(e);
 
 			hotspots.Clear();
 
 			PaintGrid(e);
 			PaintDays(e);
+
+			ResumeLayout();
 		}
 
 
 		private void PaintGrid(PaintEventArgs e)
 		{
-			e.Graphics.Clear(Color.White);
+			e.Graphics.Clear(Theme.BackColor);
 
 			// day of week names...
 
-			var dowFont = new Font("Segoe UI Light", 10.0f, FontStyle.Regular);
+			using var dowFont = new Font("Segoe UI Light", 10.0f, FontStyle.Regular);
 			var culture = Thread.CurrentThread.CurrentUICulture.DateTimeFormat;
-			dowOffset = dowFont.Height + 2;
+			dowOffset = dowFont.Height;
 
-			var dowFormat = new StringFormat
+			using var dowFormat = new StringFormat
 			{
 				Alignment = StringAlignment.Center,
 				FormatFlags = StringFormatFlags.NoWrap | StringFormatFlags.LineLimit,
@@ -324,14 +330,15 @@ private void PaintGrid(PaintEventArgs e)
 
 			// day names and vertical lines...
 
-			var pen = new Pen(Color.DarkGray, 0.1f);
+			using var pen = new Pen(Theme.MonthGrid, 0.1f);
 			var dow = firstDow == DayOfWeek.Sunday ? 0 : 1;
 
 			for (int i = 0; i < 7; i++, dow++)
 			{
 				var name = culture.GetDayName((DayOfWeek)(dow % 7)).ToUpper();
 				var clip = new Rectangle(dayWidth * i, 1, dayWidth, dowFont.Height + 2);
-				e.Graphics.DrawString(name, dowFont, Brushes.SlateGray, clip, dowFormat);
+				using var brush = new SolidBrush(Theme.MonthDayFore);
+				e.Graphics.DrawString(name, dowFont, brush, clip, dowFormat);
 
 				if (i < 6)
 				{
@@ -350,10 +357,6 @@ private void PaintGrid(PaintEventArgs e)
 					0, i * dayHeight + dowOffset,
 					e.ClipRectangle.Width, i * dayHeight + dowOffset);
 			}
-
-			dowFormat.Dispose();
-			dowFont.Dispose();
-			pen.Dispose();
 		}
 
 
@@ -364,10 +367,13 @@ private void PaintDays(PaintEventArgs e)
 			var row = 0;
 			var col = 0;
 
-			var headFont = new Font("Segoe UI", 10.0f, FontStyle.Regular);
-			var headFore = new SolidBrush(ColorTranslator.FromHtml(TodayHeadColor));
-			var headBack = new SolidBrush(ColorTranslator.FromHtml(HeadBackColor));
-			var headPen = new Pen(Color.DarkGray, 0.1f);
+			using var headFont = new Font("Segoe UI", 10.0f, FontStyle.Regular);
+			using var headFore = new SolidBrush(Theme.MonthDayFore);
+			using var headBack = new SolidBrush(Theme.MonthDayBack);
+			using var todayBack = new SolidBrush(Theme.MonthTodayBack);
+			using var gridPen = new Pen(Theme.MonthGrid, 0.1f);
+			using var inbrush = new SolidBrush(Theme.MonthTodayFore);
+			using var outbrush = new SolidBrush(Theme.MonthDayFore);
 
 			// how many lines fit in each day box
 			maxItems = (((Height - dowOffset) / weeks) - headFont.Height - 2) / Font.Height;
@@ -382,15 +388,17 @@ private void PaintDays(PaintEventArgs e)
 					col * dayWidth, row * dayHeight + dowOffset,
 					dayWidth, headFont.Height + 2);
 
+				var today = day.Date.Date.Equals(now.Date);
+
 				e.Graphics.FillRectangle(
 					// compare only date part
-					day.Date.Date.Equals(now.Date) ? headFore : headBack,
+					today ? todayBack : headBack,
 					box);
 
-				e.Graphics.DrawRectangle(headPen, box);
+				e.Graphics.DrawRectangle(gridPen, box);
 
 				e.Graphics.DrawString(day.Date.Day.ToString(), headFont,
-					day.InMonth ? Brushes.Black : Brushes.Gray,
+					day.InMonth ? inbrush : outbrush,
 					box.X + 3, box.Y + 1);
 
 				// record day header box
@@ -417,17 +425,13 @@ private void PaintDays(PaintEventArgs e)
 					row++;
 				}
 			}
-
-			headFore.Dispose();
-			headFont.Dispose();
-			headBack.Dispose();
-			headPen.Dispose();
 		}
 
 
 		private void PaintDay(Graphics g, CalendarDay day)
 		{
-			g.FillRectangle(day.InMonth ? Brushes.White : Brushes.WhiteSmoke, day.Bounds);
+			using var backBrush = new SolidBrush(day.InMonth ? Theme.MonthPrimary : Theme.MonthSecondary);
+			g.FillRectangle(backBrush, day.Bounds);
 
 			if (day.Pages.Count == 0)
 			{
@@ -461,8 +465,11 @@ private void PaintDay(Graphics g, CalendarDay day)
 					width, Font.Height);
 
 				var font = page.IsDeleted ? deletedFont : Font;
-				g.DrawString(page.Title, font,
-					page.IsDeleted || !day.InMonth ? Brushes.Gray : Brushes.Black, clip, format);
+				using var brush = new SolidBrush(page.IsDeleted || day.InMonth 
+					? Theme.MonthTodayFore
+					: Theme.MonthDayFore);
+
+				g.DrawString(page.Title, font, brush, clip, format);
 
 				// actual length of string for hyperlink hovering
 				var size = g.MeasureString(page.Title, font, clip.Width, format).ToSize();
@@ -531,7 +538,8 @@ private void MakeScrollButton(Hottype type, CalendarDay day, Point location)
 			var button = new MoreButton
 			{
 				Font = moreFont,
-				ForeColor = AppColors.ControlColor,
+				PreferredBack = Theme.MonthPrimary,
+				PreferredFore = Theme.LinkColor,
 				Location = location,
 				Text = type == Hottype.Up ? LessGlyph : MoreGlyph,
 				Size = new Size(moreSize.Width + 4, moreSize.Height + 2),
diff --git a/OneMoreCalendar/OneMoreCalendar.csproj b/OneMoreCalendar/OneMoreCalendar.csproj
index de6d6ecb99..00ccfe7589 100644
--- a/OneMoreCalendar/OneMoreCalendar.csproj
+++ b/OneMoreCalendar/OneMoreCalendar.csproj
@@ -1,6 +1,9 @@
 <?xml version="1.0" encoding="utf-8"?>
 <Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <LangVersion>9.0</LangVersion>
+  </PropertyGroup>
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
@@ -63,7 +66,7 @@
     <Compile Include="DetailView.Designer.cs">
       <DependentUpon>DetailView.cs</DependentUpon>
     </Compile>
-    <Compile Include="Things\AppColors.cs" />
+    <Compile Include="Things\Theme.cs" />
     <Compile Include="Things\BitmapExtensions.cs" />
     <Compile Include="Things\DateTimeExtensions.cs" />
     <Compile Include="Things\GraphicsExtensions.cs" />
@@ -117,6 +120,12 @@
     <Compile Include="SnapshotForm.Designer.cs">
       <DependentUpon>SnapshotForm.cs</DependentUpon>
     </Compile>
+    <Compile Include="Things\ThemedForm.cs">
+      <SubType>Form</SubType>
+    </Compile>
+    <Compile Include="Things\ThemedUserControl.cs">
+      <SubType>UserControl</SubType>
+    </Compile>
     <Compile Include="YearsForm.cs">
       <SubType>Form</SubType>
     </Compile>
diff --git a/OneMoreCalendar/OneNoteProvider.cs b/OneMoreCalendar/OneNoteProvider.cs
index 6d0d31132d..6656003719 100644
--- a/OneMoreCalendar/OneNoteProvider.cs
+++ b/OneMoreCalendar/OneNoteProvider.cs
@@ -197,12 +197,11 @@ public async Task NavigateTo(string pageID)
 			using (one = new OneNote())
 			{
 				var url = one.GetHyperlink(pageID, string.Empty);
-				if (url != null)
+				if (!string.IsNullOrEmpty(url))
 				{
 					await one.NavigateTo(url);
 				}
 			}
-
 		}
 	}
 }
diff --git a/OneMoreCalendar/Properties/AssemblyInfo.cs b/OneMoreCalendar/Properties/AssemblyInfo.cs
index 381100e113..97c495e96d 100644
Binary files a/OneMoreCalendar/Properties/AssemblyInfo.cs and b/OneMoreCalendar/Properties/AssemblyInfo.cs differ
diff --git a/OneMoreCalendar/SettingsForm.Designer.cs b/OneMoreCalendar/SettingsForm.Designer.cs
index b2fa2cd7be..b6a356f7db 100644
--- a/OneMoreCalendar/SettingsForm.Designer.cs
+++ b/OneMoreCalendar/SettingsForm.Designer.cs
@@ -1,4 +1,6 @@
-namespace OneMoreCalendar
+using System.Drawing;
+
+namespace OneMoreCalendar
 {
 	partial class SettingsForm
 	{
@@ -30,6 +32,7 @@ private void InitializeComponent()
 		{
 			this.optionsLabel = new System.Windows.Forms.Label();
 			this.notebooksLabel = new System.Windows.Forms.Label();
+			this.themeLabel = new System.Windows.Forms.Label();
 			this.settingsPanel = new System.Windows.Forms.Panel();
 			this.emptyBox = new OneMoreCalendar.MoreCheckBox();
 			this.deletedBox = new OneMoreCalendar.MoreCheckBox();
@@ -38,6 +41,9 @@ private void InitializeComponent()
 			this.notebooksBox = new OneMoreCalendar.MoreCheckedListBox();
 			this.createdBox = new OneMoreCalendar.MoreCheckBox();
 			this.modifiedBox = new OneMoreCalendar.MoreCheckBox();
+			this.darkModeButton = new OneMoreCalendar.MoreRadioButton();
+			this.lightModeButton = new OneMoreCalendar.MoreRadioButton();
+			this.systemModeButton = new OneMoreCalendar.MoreRadioButton();
 			this.logLink = new River.OneMoreAddIn.UI.MoreLinkLabel();
 			this.aboutLink = new River.OneMoreAddIn.UI.MoreLinkLabel();
 			this.settingsPanel.SuspendLayout();
@@ -60,12 +66,23 @@ private void InitializeComponent()
 			this.notebooksLabel.AutoSize = true;
 			this.notebooksLabel.Font = new System.Drawing.Font("Segoe UI", 12F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
 			this.notebooksLabel.ForeColor = System.Drawing.Color.FromArgb(((int)(((byte)(115)))), ((int)(((byte)(53)))), ((int)(((byte)(110)))));
-			this.notebooksLabel.Location = new System.Drawing.Point(23, 215);
+			this.notebooksLabel.Location = new System.Drawing.Point(23, 349);
 			this.notebooksLabel.Name = "notebooksLabel";
 			this.notebooksLabel.Size = new System.Drawing.Size(131, 32);
 			this.notebooksLabel.TabIndex = 1;
 			this.notebooksLabel.Text = "Notebooks";
 			// 
+			// themeLabel
+			// 
+			this.themeLabel.AutoSize = true;
+			this.themeLabel.Font = new System.Drawing.Font("Segoe UI", 12F, System.Drawing.FontStyle.Regular, System.Drawing.GraphicsUnit.Point, ((byte)(0)));
+			this.themeLabel.ForeColor = System.Drawing.Color.FromArgb(((int)(((byte)(115)))), ((int)(((byte)(53)))), ((int)(((byte)(110)))));
+			this.themeLabel.Location = new System.Drawing.Point(22, 202);
+			this.themeLabel.Name = "themeLabel";
+			this.themeLabel.Size = new System.Drawing.Size(88, 32);
+			this.themeLabel.TabIndex = 1;
+			this.themeLabel.Text = "Theme";
+			// 
 			// settingsPanel
 			// 
 			this.settingsPanel.BackColor = System.Drawing.Color.Transparent;
@@ -78,14 +95,18 @@ private void InitializeComponent()
 			this.settingsPanel.Controls.Add(this.modifiedBox);
 			this.settingsPanel.Controls.Add(this.notebooksLabel);
 			this.settingsPanel.Controls.Add(this.optionsLabel);
+			this.settingsPanel.Controls.Add(this.themeLabel);
+			this.settingsPanel.Controls.Add(this.darkModeButton);
+			this.settingsPanel.Controls.Add(this.lightModeButton);
+			this.settingsPanel.Controls.Add(this.systemModeButton);
 			this.settingsPanel.Controls.Add(this.logLink);
 			this.settingsPanel.Controls.Add(this.aboutLink);
 			this.settingsPanel.Dock = System.Windows.Forms.DockStyle.Fill;
-			this.settingsPanel.Location = new System.Drawing.Point(0, 0);
+			this.settingsPanel.Location = new System.Drawing.Point(4, 4);
 			this.settingsPanel.Margin = new System.Windows.Forms.Padding(0);
 			this.settingsPanel.Name = "settingsPanel";
-			this.settingsPanel.Padding = new System.Windows.Forms.Padding(20);
-			this.settingsPanel.Size = new System.Drawing.Size(518, 486);
+			this.settingsPanel.Padding = new System.Windows.Forms.Padding(20, 20, 10, 10);
+			this.settingsPanel.Size = new System.Drawing.Size(507, 598);
 			this.settingsPanel.TabIndex = 2;
 			// 
 			// emptyBox
@@ -115,8 +136,10 @@ private void InitializeComponent()
 			this.okButton.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right)));
 			this.okButton.BackColor = System.Drawing.SystemColors.Window;
 			this.okButton.DialogResult = System.Windows.Forms.DialogResult.OK;
-			this.okButton.Location = new System.Drawing.Point(349, 439);
+			this.okButton.Location = new System.Drawing.Point(338, 551);
 			this.okButton.Name = "okButton";
+			this.okButton.PreferredBack = System.Drawing.Color.Empty;
+			this.okButton.PreferredFore = System.Drawing.Color.Empty;
 			this.okButton.ShowBorder = true;
 			this.okButton.Size = new System.Drawing.Size(75, 34);
 			this.okButton.TabIndex = 9;
@@ -129,8 +152,10 @@ private void InitializeComponent()
 			this.cancelButton.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Right)));
 			this.cancelButton.BackColor = System.Drawing.SystemColors.Window;
 			this.cancelButton.DialogResult = System.Windows.Forms.DialogResult.Cancel;
-			this.cancelButton.Location = new System.Drawing.Point(430, 439);
+			this.cancelButton.Location = new System.Drawing.Point(419, 551);
 			this.cancelButton.Name = "cancelButton";
+			this.cancelButton.PreferredBack = System.Drawing.Color.Empty;
+			this.cancelButton.PreferredFore = System.Drawing.Color.Empty;
 			this.cancelButton.ShowBorder = true;
 			this.cancelButton.Size = new System.Drawing.Size(75, 34);
 			this.cancelButton.TabIndex = 8;
@@ -146,9 +171,9 @@ private void InitializeComponent()
 			this.notebooksBox.BorderStyle = System.Windows.Forms.BorderStyle.None;
 			this.notebooksBox.CheckOnClick = true;
 			this.notebooksBox.FormattingEnabled = true;
-			this.notebooksBox.Location = new System.Drawing.Point(48, 264);
+			this.notebooksBox.Location = new System.Drawing.Point(48, 398);
 			this.notebooksBox.Name = "notebooksBox";
-			this.notebooksBox.Size = new System.Drawing.Size(445, 138);
+			this.notebooksBox.Size = new System.Drawing.Size(446, 138);
 			this.notebooksBox.TabIndex = 7;
 			this.notebooksBox.ItemCheck += new System.Windows.Forms.ItemCheckEventHandler(this.ValidateCheckedItems);
 			// 
@@ -178,14 +203,53 @@ private void InitializeComponent()
 			this.modifiedBox.UseVisualStyleBackColor = false;
 			this.modifiedBox.CheckedChanged += new System.EventHandler(this.ChangeFilter);
 			// 
+			// darkModeButton
+			// 
+			this.darkModeButton.AutoSize = true;
+			this.darkModeButton.BackColor = System.Drawing.Color.White;
+			this.darkModeButton.Location = new System.Drawing.Point(48, 246);
+			this.darkModeButton.Name = "darkModeButton";
+			this.darkModeButton.Round = true;
+			this.darkModeButton.Size = new System.Drawing.Size(68, 24);
+			this.darkModeButton.TabIndex = 12;
+			this.darkModeButton.Text = "Dark";
+			this.darkModeButton.UseVisualStyleBackColor = false;
+			// 
+			// lightModeButton
+			// 
+			this.lightModeButton.AutoSize = true;
+			this.lightModeButton.BackColor = System.Drawing.Color.White;
+			this.lightModeButton.Location = new System.Drawing.Point(47, 276);
+			this.lightModeButton.Name = "lightModeButton";
+			this.lightModeButton.Round = true;
+			this.lightModeButton.Size = new System.Drawing.Size(69, 24);
+			this.lightModeButton.TabIndex = 13;
+			this.lightModeButton.Text = "Light";
+			this.lightModeButton.UseVisualStyleBackColor = false;
+			// 
+			// systemModeButton
+			// 
+			this.systemModeButton.AutoSize = true;
+			this.systemModeButton.BackColor = System.Drawing.Color.White;
+			this.systemModeButton.Checked = true;
+			this.systemModeButton.Location = new System.Drawing.Point(47, 306);
+			this.systemModeButton.Name = "systemModeButton";
+			this.systemModeButton.Round = true;
+			this.systemModeButton.Size = new System.Drawing.Size(87, 24);
+			this.systemModeButton.TabIndex = 14;
+			this.systemModeButton.TabStop = true;
+			this.systemModeButton.Text = "System";
+			this.systemModeButton.UseVisualStyleBackColor = false;
+			// 
 			// logLink
 			// 
 			this.logLink.ActiveLinkColor = System.Drawing.Color.DarkOrchid;
 			this.logLink.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left)));
 			this.logLink.AutoSize = true;
 			this.logLink.Cursor = System.Windows.Forms.Cursors.Hand;
+			this.logLink.HoverColor = System.Drawing.Color.MediumOrchid;
 			this.logLink.LinkColor = System.Drawing.SystemColors.ControlDark;
-			this.logLink.Location = new System.Drawing.Point(15, 444);
+			this.logLink.Location = new System.Drawing.Point(24, 558);
 			this.logLink.Margin = new System.Windows.Forms.Padding(4, 0, 4, 0);
 			this.logLink.MaximumSize = new System.Drawing.Size(420, 0);
 			this.logLink.Name = "logLink";
@@ -201,8 +265,9 @@ private void InitializeComponent()
 			this.aboutLink.Anchor = ((System.Windows.Forms.AnchorStyles)((System.Windows.Forms.AnchorStyles.Bottom | System.Windows.Forms.AnchorStyles.Left)));
 			this.aboutLink.AutoSize = true;
 			this.aboutLink.Cursor = System.Windows.Forms.Cursors.Hand;
+			this.aboutLink.HoverColor = System.Drawing.Color.MediumOrchid;
 			this.aboutLink.LinkColor = System.Drawing.SystemColors.ControlDark;
-			this.aboutLink.Location = new System.Drawing.Point(135, 444);
+			this.aboutLink.Location = new System.Drawing.Point(144, 558);
 			this.aboutLink.Margin = new System.Windows.Forms.Padding(4, 0, 4, 0);
 			this.aboutLink.MaximumSize = new System.Drawing.Size(420, 0);
 			this.aboutLink.Name = "aboutLink";
@@ -217,13 +282,15 @@ private void InitializeComponent()
 			this.AutoScaleDimensions = new System.Drawing.SizeF(9F, 20F);
 			this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
 			this.BackColor = System.Drawing.Color.White;
-			this.ClientSize = new System.Drawing.Size(518, 486);
+			this.ClientSize = new System.Drawing.Size(515, 606);
 			this.Controls.Add(this.settingsPanel);
+			this.ForeColor = System.Drawing.Color.FromArgb(((int)(((byte)(230)))), ((int)(((byte)(230)))), ((int)(((byte)(230)))));
 			this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.None;
 			this.KeyPreview = true;
 			this.MaximizeBox = false;
 			this.MinimizeBox = false;
 			this.Name = "SettingsForm";
+			this.Padding = new System.Windows.Forms.Padding(4);
 			this.ShowIcon = false;
 			this.ShowInTaskbar = false;
 			this.StartPosition = System.Windows.Forms.FormStartPosition.Manual;
@@ -239,6 +306,7 @@ private void InitializeComponent()
 
 		private System.Windows.Forms.Label optionsLabel;
 		private System.Windows.Forms.Label notebooksLabel;
+		private System.Windows.Forms.Label themeLabel;
 		private System.Windows.Forms.Panel settingsPanel;
 		private MoreCheckBox createdBox;
 		private MoreCheckBox modifiedBox;
@@ -246,6 +314,9 @@ private void InitializeComponent()
 		private MoreButton okButton;
 		private MoreButton cancelButton;
 		private MoreCheckBox deletedBox;
+		private MoreRadioButton lightModeButton;
+		private MoreRadioButton darkModeButton;
+		private MoreRadioButton systemModeButton;
 		private River.OneMoreAddIn.UI.MoreLinkLabel logLink;
 		private River.OneMoreAddIn.UI.MoreLinkLabel aboutLink;
 		private MoreCheckBox emptyBox;
diff --git a/OneMoreCalendar/SettingsForm.cs b/OneMoreCalendar/SettingsForm.cs
index 196b781df0..983b81434a 100644
--- a/OneMoreCalendar/SettingsForm.cs
+++ b/OneMoreCalendar/SettingsForm.cs
@@ -40,6 +40,13 @@ protected override async void OnLoad(EventArgs e)
 				deletedBox.Checked = provider.Deleted;
 				emptyBox.Checked = !provider.Empty;
 
+				switch (provider.Theme)
+				{
+					case ThemeMode.Light: lightModeButton.Checked = true; break;
+					case ThemeMode.Dark: darkModeButton.Checked = true; break;
+					default: systemModeButton.Checked = true; break;
+				}
+
 				var notebooks = await provider.GetNotebooks();
 				notebooksBox.Items.Clear();
 				foreach (var notebook in notebooks)
@@ -140,6 +147,11 @@ private void Apply(object sender, EventArgs e)
 				createdBox.Checked, modifiedBox.Checked,
 				deletedBox.Checked, !emptyBox.Checked);
 
+			provider.SetTheme(
+				lightModeButton.Checked
+				? ThemeMode.Light
+				: darkModeButton.Checked ? ThemeMode.Dark : ThemeMode.System);
+
 			var ids = new List<string>();
 			foreach (Notebook notebook in notebooksBox.CheckedItems)
 			{
diff --git a/OneMoreCalendar/SettingsProvider.cs b/OneMoreCalendar/SettingsProvider.cs
index 482d862fb0..8fffc47362 100644
--- a/OneMoreCalendar/SettingsProvider.cs
+++ b/OneMoreCalendar/SettingsProvider.cs
@@ -11,7 +11,9 @@ namespace OneMoreCalendar
 	using System.Linq;
 	using System.Threading.Tasks;
 	using System.Windows.Forms;
+	using System.Windows.Forms.VisualStyles;
 	using System.Xml.Linq;
+	using System.Xml.Serialization;
 
 
 	/// <summary>
@@ -43,10 +45,7 @@ public SettingsProvider()
 				}
 			}
 
-			if (root == null)
-			{
-				root = new XElement("settings");
-			}
+			root ??= new XElement("settings");
 
 			var filters = root.Element("filters");
 			if (filters == null)
@@ -65,6 +64,12 @@ public SettingsProvider()
 					root.Add(notebooks);
 				}
 			}
+
+			var theme = root.Elements("theme");
+			if (theme == null)
+			{
+				root.Add(new XElement("theme", ThemeMode.System.ToString()));
+			}
 		}
 
 
@@ -91,6 +96,21 @@ public bool Empty
 			root.Elements("filters").Elements("modified").Any(e => e.Value.Equals("true"));
 
 
+		public ThemeMode Theme
+		{
+			get
+			{
+				var element = root.Elements("theme").FirstOrDefault();
+				if (element != null)
+				{
+					return (ThemeMode)Enum.Parse(typeof(ThemeMode), element.Value);
+				}
+
+				return ThemeMode.System;
+			}
+		}
+
+
 		public async Task<IEnumerable<string>> GetNotebookIDs()
 		{
 			var ids = root.Elements("notebooks").Elements("notebook").Select(e => e.Value);
@@ -172,6 +192,20 @@ public void SetNotebookIDs(IEnumerable<string> ids)
 		}
 
 
+		public void SetTheme(ThemeMode mode)
+		{
+			var theme = root.Element("theme");
+			if (theme == null)
+			{
+				root.Add(new XElement("theme", mode.ToString()));
+			}
+			else
+			{
+				theme.Value = mode.ToString();
+			}
+		}
+
+
 		public void Save()
 		{
 			PathHelper.EnsurePathExists(Path.GetDirectoryName(path));
diff --git a/OneMoreCalendar/SnapshotForm.cs b/OneMoreCalendar/SnapshotForm.cs
index d60e4202d5..7f01562e84 100644
--- a/OneMoreCalendar/SnapshotForm.cs
+++ b/OneMoreCalendar/SnapshotForm.cs
@@ -24,6 +24,8 @@ public SnapshotForm()
 			: base()
 		{
 			InitializeComponent();
+
+			StaticColors = true;
 		}
 
 
@@ -54,28 +56,25 @@ protected override void OnLoad(EventArgs e)
 
 			if (!DesignMode && File.Exists(Path))
 			{
-				using (var source = new Metafile(Path))
-				{
-					var target = new Bitmap(pictureBox.Width, pictureBox.Height);
-					using (var g = Graphics.FromImage(target))
-					{
-						// resize the image 150%
-						g.DrawImage(source,
-							new Rectangle(0, 0, (int)(target.Width * 1.5), (int)(target.Height * 1.5)),
-							new Rectangle(0, 0, source.Width, source.Height),
-							GraphicsUnit.Pixel
-							);
-
-						//var path = System.IO.Path.Combine(
-						//	System.IO.Path.GetTempPath(),
-						//	System.IO.Path.GetRandomFileName() + ".png");
-
-						//target.Save(path, ImageFormat.Png);
-						//pictureBox.ImageLocation = path;
-
-						pictureBox.Image = target;
-					}
-				}
+				using var source = new Metafile(Path);
+				var target = new Bitmap(pictureBox.Width, pictureBox.Height);
+				using var g = Graphics.FromImage(target);
+
+				// resize the image 150%
+				g.DrawImage(source,
+					new Rectangle(0, 0, (int)(target.Width * 1.5), (int)(target.Height * 1.5)),
+					new Rectangle(0, 0, source.Width, source.Height),
+					GraphicsUnit.Pixel
+					);
+
+				//var path = System.IO.Path.Combine(
+				//	System.IO.Path.GetTempPath(),
+				//	System.IO.Path.GetRandomFileName() + ".png");
+
+				//target.Save(path, ImageFormat.Png);
+				//pictureBox.ImageLocation = path;
+
+				pictureBox.Image = target;
 			}
 		}
 
diff --git a/OneMoreCalendar/Things/AppColors.cs b/OneMoreCalendar/Things/AppColors.cs
deleted file mode 100644
index d1011f27a9..0000000000
--- a/OneMoreCalendar/Things/AppColors.cs
+++ /dev/null
@@ -1,27 +0,0 @@
-//************************************************************************************************
-// Copyright © 2022 Steven M Cohn.  All rights reserved.
-//************************************************************************************************
-
-namespace OneMoreCalendar
-{
-	using System.Drawing;
-
-
-	internal static class AppColors
-	{
-
-		public static Color ControlColor => ColorTranslator.FromHtml("#FF73356E");
-
-		public static Brush HoverBrush => new SolidBrush(ColorTranslator.FromHtml("#FFF7EDF7"));
-
-		public static Pen HoverPen => new Pen(ColorTranslator.FromHtml("#FFF0DAEE"));
-
-		public static Brush RowBrush => new SolidBrush(ColorTranslator.FromHtml("#FFFDFAFE"));
-
-		public static Brush PressedBrush => new SolidBrush(ColorTranslator.FromHtml("#FFF0DAEE"));
-
-		public static Pen PressedPen => new Pen(ColorTranslator.FromHtml("#FF9E5499"));
-
-		public static Brush TextBrush => new SolidBrush(Color.FromArgb(115, 53, 110));
-	}
-}
diff --git a/OneMoreCalendar/Things/BitmapExtensions.cs b/OneMoreCalendar/Things/BitmapExtensions.cs
index 06665acdea..3293226c57 100644
--- a/OneMoreCalendar/Things/BitmapExtensions.cs
+++ b/OneMoreCalendar/Things/BitmapExtensions.cs
@@ -28,17 +28,15 @@ public static Bitmap ConvertToGrayscale(this Bitmap original)
 					new float[] { 0,     0,     0,     0, 1}
 				});
 
-				using (var attributes = new ImageAttributes())
-				{
-					attributes.SetColorMatrix(colorMatrix);
-
-					// redraw original image onto new image using grayscale color matrix
-					g.DrawImage(original,
-						new Rectangle(0, 0, original.Width, original.Height),
-						0, 0, original.Width, original.Height,
-						GraphicsUnit.Pixel,
-						attributes);
-				}
+				using var attributes = new ImageAttributes();
+				attributes.SetColorMatrix(colorMatrix);
+
+				// redraw original image onto new image using grayscale color matrix
+				g.DrawImage(original,
+					new Rectangle(0, 0, original.Width, original.Height),
+					0, 0, original.Width, original.Height,
+					GraphicsUnit.Pixel,
+					attributes);
 			}
 
 			return grayscale;
diff --git a/OneMoreCalendar/Things/GraphicsExtensions.cs b/OneMoreCalendar/Things/GraphicsExtensions.cs
index f95ff7031d..f27bd46a40 100644
--- a/OneMoreCalendar/Things/GraphicsExtensions.cs
+++ b/OneMoreCalendar/Things/GraphicsExtensions.cs
@@ -27,10 +27,8 @@ public static void DrawRoundedRectangle(
 			if (pen == null)
 				throw new ArgumentNullException(nameof(pen), "cannot be null");
 
-			using (var path = CreateRoundedRectangle(bounds, cornerRadius))
-			{
-				graphics.DrawPath(pen, path);
-			}
+			using var path = CreateRoundedRectangle(bounds, cornerRadius);
+			graphics.DrawPath(pen, path);
 		}
 
 
@@ -50,10 +48,8 @@ public static void FillRoundedRectangle(
 			if (brush == null)
 				throw new ArgumentNullException(nameof(brush), "cannot be null");
 
-			using (var path = CreateRoundedRectangle(bounds, cornerRadius))
-			{
-				graphics.FillPath(brush, path);
-			}
+			using var path = CreateRoundedRectangle(bounds, cornerRadius);
+			graphics.FillPath(brush, path);
 		}
 
 
diff --git a/OneMoreCalendar/Things/MoreButton.cs b/OneMoreCalendar/Things/MoreButton.cs
index 6d5355728f..5cc4347343 100644
--- a/OneMoreCalendar/Things/MoreButton.cs
+++ b/OneMoreCalendar/Things/MoreButton.cs
@@ -4,6 +4,7 @@
 
 namespace OneMoreCalendar
 {
+	using River.OneMoreAddIn;
 	using System;
 	using System.ComponentModel;
 	using System.Drawing;
@@ -23,7 +24,6 @@ namespace OneMoreCalendar
 	internal class MoreButton : Button
 	{
 		private const int Radius = 4;
-		private IContainer components;
 		private MouseEventArgs downArgs = null;
 		private Image enabledImage;
 		private Timer timer;
@@ -48,7 +48,7 @@ public MoreButton()
 
 		private void InitializeComponent()
 		{
-			components = new Container();
+			var components = new Container();
 			timer = new Timer(components);
 			SuspendLayout();
 			timer.Tick += new EventHandler(Tick);
@@ -69,6 +69,18 @@ private void InitializeComponent()
 		public MouseState MouseState { get; private set; }
 
 
+		/// <summary>
+		/// Gets or sets the preferred background color
+		/// </summary>
+		public Color PreferredBack { get; set; } = Color.Empty;
+
+
+		/// <summary>
+		/// Gets or sets the preferred foreground color
+		/// </summary>
+		public Color PreferredFore { get; set; } = Color.Empty;
+
+
 		/// <summary>
 		/// Interval between repeat firings
 		/// </summary>
@@ -86,20 +98,21 @@ private void InitializeComponent()
 		protected override void OnPaint(PaintEventArgs pevent)
 		{
 			var g = pevent.Graphics;
-			g.Clear(BackColor);
+			g.Clear(PreferredBack.IsEmpty ? Theme.BackColor : PreferredBack);
 
 			if (Enabled && MouseState != MouseState.None)
 			{
-				g.FillRoundedRectangle(
-					MouseState.HasFlag(MouseState.Pushed) ? AppColors.PressedBrush : AppColors.HoverBrush,
-					pevent.ClipRectangle, Radius);
+				using var brush = new SolidBrush(Theme.ButtonHotBack);
+				g.FillRoundedRectangle(brush, pevent.ClipRectangle, Radius);
 			}
 
 			if (ShowBorder || (Enabled && MouseState != MouseState.None))
 			{
-				g.DrawRoundedRectangle(
-					MouseState.HasFlag(MouseState.Pushed) ? AppColors.PressedPen : AppColors.HoverPen,
-					pevent.ClipRectangle, Radius);
+				using var pen = new Pen(
+					MouseState.HasFlag(MouseState.Pushed) ? Theme.ButtonPressBorder : 
+					MouseState.HasFlag(MouseState.Hover) ? Theme.ButtonHotBorder : Theme.ButtonBorder);
+
+				g.DrawRoundedRectangle(pen, pevent.ClipRectangle, Radius);
 			}
 
 			if (Image != null)
@@ -113,17 +126,18 @@ protected override void OnPaint(PaintEventArgs pevent)
 			if (!string.IsNullOrEmpty(Text))
 			{
 				var size = g.MeasureString(Text, Font);
-				using (var brush = new SolidBrush(Enabled ? ForeColor : Color.Gray))
-				{
-					g.DrawString(Text, Font, brush,
-						(pevent.ClipRectangle.Width - size.Width) / 2,
-						(pevent.ClipRectangle.Height - size.Height) / 2,
-						new StringFormat
-						{
-							Trimming = StringTrimming.EllipsisCharacter,
-							FormatFlags = StringFormatFlags.LineLimit | StringFormatFlags.NoWrap
-						});
-				}
+				using var brush = new SolidBrush(Enabled 
+					? PreferredFore.IsEmpty ? Theme.ButtonFore : PreferredFore
+					: Theme.ButtonDisabled);
+
+				g.DrawString(Text, Font, brush,
+					(pevent.ClipRectangle.Width - size.Width) / 2,
+					(pevent.ClipRectangle.Height - size.Height) / 2,
+					new StringFormat
+					{
+						Trimming = StringTrimming.EllipsisCharacter,
+						FormatFlags = StringFormatFlags.LineLimit | StringFormatFlags.NoWrap
+					});
 			}
 		}
 
diff --git a/OneMoreCalendar/Things/MoreCheckBox.cs b/OneMoreCalendar/Things/MoreCheckBox.cs
index fbc7596ba1..ed0cae49ea 100644
--- a/OneMoreCalendar/Things/MoreCheckBox.cs
+++ b/OneMoreCalendar/Things/MoreCheckBox.cs
@@ -46,15 +46,17 @@ protected override void OnPaint(PaintEventArgs pevent)
 			{
 				if (Enabled && (MouseState != MouseState.None || Checked))
 				{
-					var brush = MouseState.HasFlag(MouseState.Pushed) || Checked
-						? AppColors.PressedBrush
-						: AppColors.HoverBrush;
+					using var brush = new SolidBrush(
+						MouseState.HasFlag(MouseState.Pushed) || Checked
+						? Theme.ButtonHotBack
+						: Theme.ButtonBack);
 
 					g.FillRoundedRectangle(brush, pevent.ClipRectangle, Radius);
 
-					var pen = MouseState.HasFlag(MouseState.Pushed) || Checked
-						? AppColors.PressedPen
-						: AppColors.HoverPen;
+					using var pen = new Pen(
+						MouseState.HasFlag(MouseState.Pushed) || Checked
+						? Theme.ButtonPressBorder
+						: Theme.Border);
 
 					g.DrawRoundedRectangle(pen, pevent.ClipRectangle, Radius);
 				}
@@ -66,33 +68,28 @@ protected override void OnPaint(PaintEventArgs pevent)
 			}
 			else
 			{
-				using (var pen = new Pen(AppColors.ControlColor))
-				{
-					g.DrawRectangle(pen, 0, 1, 14, 14);
-				}
+				using var pen = new Pen(Theme.Control);
+				g.DrawRectangle(pen, 0, 1, 14, 14);
 
 				if (Checked)
 				{
-					using (var brush = new SolidBrush(AppColors.ControlColor))
-					{
-						g.FillRectangle(brush, 2, 3, 11, 11);
-					}
+					using var backBrush = new SolidBrush(Theme.Control);
+					g.FillRectangle(backBrush, 2, 3, 11, 11);
 				}
 
 				var size = g.MeasureString(Text, Font);
-				using (var brush = new SolidBrush(ForeColor))
-				{
-					g.DrawString(Text, Font, brush,
-						new Rectangle(16, // standard icon size
-							(pevent.ClipRectangle.Height - (int)size.Height) / 2,
-							pevent.ClipRectangle.Width - 16,
-							(int)size.Height),
-						new StringFormat
-						{
-							Trimming = StringTrimming.EllipsisCharacter,
-							FormatFlags = StringFormatFlags.LineLimit | StringFormatFlags.NoWrap
-						});
-				}
+				using var brush = new SolidBrush(ForeColor);
+
+				g.DrawString(Text, Font, brush,
+					new Rectangle(16, // standard icon size
+						(pevent.ClipRectangle.Height - (int)size.Height) / 2,
+						pevent.ClipRectangle.Width - 16,
+						(int)size.Height),
+					new StringFormat
+					{
+						Trimming = StringTrimming.EllipsisCharacter,
+						FormatFlags = StringFormatFlags.LineLimit | StringFormatFlags.NoWrap
+					});
 			}
 		}
 
diff --git a/OneMoreCalendar/Things/MoreCheckedListBox.cs b/OneMoreCalendar/Things/MoreCheckedListBox.cs
index dc381ce957..2301bb3cb2 100644
--- a/OneMoreCalendar/Things/MoreCheckedListBox.cs
+++ b/OneMoreCalendar/Things/MoreCheckedListBox.cs
@@ -10,8 +10,6 @@ namespace OneMoreCalendar
 
 	internal class MoreCheckedListBox : CheckedListBox
 	{
-        private const string BoxColor = "#FF73356E";
-
 
         public MoreCheckedListBox()
             : base()
@@ -29,23 +27,16 @@ protected override void OnDrawItem(DrawItemEventArgs e)
 
 			var g = e.Graphics;
 
-			using (var brush = new SolidBrush(BackColor))
-			{
-				g.FillRectangle(brush, 0, e.Bounds.Y, e.Bounds.Width, 16);
-			}
+			using var fill = new SolidBrush(BackColor);
+			g.FillRectangle(fill, 0, e.Bounds.Y, e.Bounds.Width, 16);
 
-			var boxColor = ColorTranslator.FromHtml(BoxColor);
-			using (var pen = new Pen(boxColor))
-			{
-				g.DrawRectangle(pen, 0, e.Bounds.Y + 1, 12, 12);
-			}
+			using var pen = new Pen(Theme.Control);
+			g.DrawRectangle(pen, 0, e.Bounds.Y + 1, 12, 12);
 
 			if (CheckedIndices.Contains(e.Index))
 			{
-				using (var brush = new SolidBrush(boxColor))
-				{
-					g.FillRectangle(brush, 2, e.Bounds.Y + 3, 9, 9);
-				}
+				using var brush = new SolidBrush(Theme.Control);
+				g.FillRectangle(brush, 2, e.Bounds.Y + 3, 9, 9);
 			}
 
 			var size = g.MeasureString(Text, Font);
diff --git a/OneMoreCalendar/Things/MoreListBox.cs b/OneMoreCalendar/Things/MoreListBox.cs
index 08c22945c6..72ee0d29cc 100644
--- a/OneMoreCalendar/Things/MoreListBox.cs
+++ b/OneMoreCalendar/Things/MoreListBox.cs
@@ -2,6 +2,7 @@
 // Copyright © 2022 Steven M. Cohn. All Rights Reserved.
 //************************************************************************************************
 
+#pragma warning disable S1144 // Unused private types or members should be removed
 #pragma warning disable S4487 // Unread "private" fields should be removed
 #pragma warning disable S3459 // Unassigned members should be removed
 
@@ -32,9 +33,9 @@ private struct ScrollInfo
 			public int Mask;
 			public int Min;
 			public int Max;
-			public int Page;
+			public int Page;            // unused but do not remove, S1144
 			public int Position;
-			public int TrackPosition;
+			public int TrackPosition;   // unused but do not remove, S1144
 		}
 
 		[DllImport("user32.dll")]
@@ -87,9 +88,13 @@ private bool Scroll(int delta)
 
 		private ScrollInfo GetScrollInfo()
 		{
-			var info = new ScrollInfo();
-			info.Mask = SIF_ALL;
+			var info = new ScrollInfo
+			{
+				Mask = SIF_ALL
+			};
+
 			info.Size = Marshal.SizeOf(info);
+
 			GetScrollInfo(Handle, SB_VERT, ref info);
 			return info;
 		}
@@ -97,8 +102,8 @@ private ScrollInfo GetScrollInfo()
 		protected override void OnMouseWheel(MouseEventArgs e)
 		{
 			base.OnMouseWheel(e);
-			var info = GetScrollInfo();
-			Logger.Current.WriteLine($"wheel delta:{e.Delta} pos:{info.Position} min:{info.Min} max:{info.Max}");
+			//var info = GetScrollInfo();
+			//Logger.Current.WriteLine($"wheel delta:{e.Delta} pos:{info.Position} min:{info.Min} max:{info.Max}");
 		}
 
 		protected override void WndProc(ref Message m)
@@ -108,7 +113,7 @@ protected override void WndProc(ref Message m)
 				if (Scrolled != null)
 				{
 					var info = GetScrollInfo();
-					Logger.Current.WriteLine($"wndproc pos:{info.Position} min:{info.Min} max:{info.Max}");
+					//Logger.Current.WriteLine($"wndproc pos:{info.Position} min:{info.Min} max:{info.Max}");
 
 					if (m.WParam.ToInt32() == SB_ENDSCROLL)
 					{
diff --git a/OneMoreCalendar/Things/MoreRadioButton.cs b/OneMoreCalendar/Things/MoreRadioButton.cs
index 212b4d26ed..217f1b6035 100644
--- a/OneMoreCalendar/Things/MoreRadioButton.cs
+++ b/OneMoreCalendar/Things/MoreRadioButton.cs
@@ -5,6 +5,7 @@
 namespace OneMoreCalendar
 {
 	using System;
+	using System.ComponentModel;
 	using System.Drawing;
 	using System.Windows.Forms;
 
@@ -35,6 +36,10 @@ public MoreRadioButton()
 		public MouseState MouseState { get; private set; }
 
 
+		[Description("Round radio if true")]
+		public bool Round { get; set; }
+
+
 		protected override void OnPaint(PaintEventArgs pevent)
 		{
 			var g = pevent.Graphics;
@@ -44,15 +49,17 @@ protected override void OnPaint(PaintEventArgs pevent)
 			{
 				if (Enabled && (MouseState != MouseState.None || Checked))
 				{
-					var brush = MouseState.HasFlag(MouseState.Pushed) || Checked
-						? AppColors.PressedBrush
-						: AppColors.HoverBrush;
+					using var brush = new SolidBrush(
+						MouseState.HasFlag(MouseState.Pushed) || Checked
+						? Theme.ButtonHotBack
+						: Theme.ButtonBack);
 
 					g.FillRoundedRectangle(brush, pevent.ClipRectangle, Radius);
 
-					var pen = MouseState.HasFlag(MouseState.Pushed) || Checked
-						? AppColors.PressedPen
-						: AppColors.HoverPen;
+					using var pen = new Pen(
+						MouseState.HasFlag(MouseState.Pushed) || Checked
+						? Theme.ButtonPressBorder
+						: Theme.Border);
 
 					g.DrawRoundedRectangle(pen, pevent.ClipRectangle, Radius);
 				}
@@ -64,14 +71,26 @@ protected override void OnPaint(PaintEventArgs pevent)
 			}
 			else
 			{
-				using (var pen = new Pen(AppColors.ControlColor))
+				using (var pen = new Pen(Theme.Control))
 				{
-					g.DrawRectangle(pen, 0, 1, 14, 14);
+					if (Round)
+					{
+						g.DrawArc(pen, 0, 1, 14, 14, 0, 360);
+					}
+					else
+					{
+						g.DrawRectangle(pen, 0, 1, 14, 14);
+					}
 				}
 
 				if (Checked)
 				{
-					using (var brush = new SolidBrush(AppColors.ControlColor))
+					using var brush = new SolidBrush(Theme.Control);
+					if (Round)
+					{
+						g.FillEllipse(brush, new Rectangle(2, 3, 10, 10));
+					}
+					else
 					{
 						g.FillRectangle(brush, 2, 3, 11, 11);
 					}
diff --git a/OneMoreCalendar/Things/RoundedForm.cs b/OneMoreCalendar/Things/RoundedForm.cs
index b3d6e040c3..acdde00bf0 100644
--- a/OneMoreCalendar/Things/RoundedForm.cs
+++ b/OneMoreCalendar/Things/RoundedForm.cs
@@ -10,7 +10,7 @@ namespace OneMoreCalendar
 	using System.Windows.Forms;
 
 
-	internal partial class RoundedForm : Form
+	internal partial class RoundedForm : ThemedForm
 	{
 
 		[DllImport("Gdi32.dll", EntryPoint = "CreateRoundRectRgn")]
@@ -36,25 +36,28 @@ public RoundedForm()
 		protected override void OnLoad(EventArgs e)
 		{
 			base.OnLoad(e);
-			FormBorderStyle = FormBorderStyle.None;
-			Region = Region.FromHrgn(CreateRoundRectRgn(0, 0, Width, Height, Radius, Radius));
+
+			if (!DesignMode)
+			{
+				FormBorderStyle = FormBorderStyle.None;
+				Region = Region.FromHrgn(CreateRoundRectRgn(0, 0, Width, Height, Radius, Radius));
+			}
 		}
 
 
 		protected override void OnPaintBackground(PaintEventArgs e)
 		{
 			//base.OnPaintBackground(e);
-			
+
 			Rectangle r;
 
-			using (var brush = new SolidBrush(BackColor))
-			{
-				r = new Rectangle(0, 0, e.ClipRectangle.Width, e.ClipRectangle.Height);
-				e.Graphics.FillRoundedRectangle(brush, r, Radius);
-			}
+			using var brush = new SolidBrush(BackColor);
+			r = new Rectangle(0, 0, e.ClipRectangle.Width, e.ClipRectangle.Height);
+			e.Graphics.FillRoundedRectangle(brush, r, Radius);
 
+			using var pen = new Pen(Theme.Border);
 			r = new Rectangle(0, 0, e.ClipRectangle.Width - 1, e.ClipRectangle.Height - 1);
-			e.Graphics.DrawRoundedRectangle(AppColors.PressedPen, r, Radius);
+			e.Graphics.DrawRoundedRectangle(pen, r, Radius);
 		}
 	}
 }
diff --git a/OneMoreCalendar/Things/Theme.cs b/OneMoreCalendar/Things/Theme.cs
new file mode 100644
index 0000000000..5f0e9eb77c
--- /dev/null
+++ b/OneMoreCalendar/Things/Theme.cs
@@ -0,0 +1,203 @@
+//************************************************************************************************
+// Copyright © 2022 Steven M Cohn.  All rights reserved.
+//************************************************************************************************
+
+namespace OneMoreCalendar
+{
+	using River.OneMoreAddIn.Helpers.Office;
+	using System;
+	using System.Drawing;
+	using System.Runtime.InteropServices;
+	using System.Windows.Forms;
+
+
+	internal enum ThemeMode
+	{
+		System = 0,
+		Light = 1,
+		Dark = 2
+	}
+
+	internal static class Theme
+	{
+		#region Native
+		private const int DWMWA_USE_IMMERSIVE_DARK_MODE = 20;
+
+		[DllImport("dwmapi.dll", PreserveSig = true)]
+		private static extern int DwmSetWindowAttribute(
+			IntPtr hwnd, int attr, ref bool attrValue, int attrSize);
+		#endregion Native
+
+
+		public static bool DarkMode { get; private set; }
+
+		public static Color BackColor { get; private set; }
+		public static Color ForeColor { get; private set; }
+		public static Color Border { get; private set; }
+		public static Color Highlight { get; private set; }
+		public static Color Control { get; private set; }
+
+		public static Color ButtonBack { get; private set; }
+		public static Color ButtonFore { get; private set; }
+		public static Color ButtonDisabled { get; private set; }
+		public static Color ButtonBorder { get; private set; }
+		public static Color ButtonHotBack { get; private set; }
+		public static Color ButtonHotBorder { get; private set; }
+		public static Color ButtonPressBorder { get; private set; }
+
+		public static Color LinkColor { get; private set; }
+		public static Color HoverColor { get; private set; }
+
+		public static Color DetailOddBack { get; private set; }
+		public static Color DetailEvenBack { get; private set; }
+
+		public static Color MonthHeader { get; private set; }
+		public static Color MonthPrimary { get; private set; }
+		public static Color MonthSecondary { get; private set; }
+		public static Color MonthGrid { get; private set; }
+		public static Color MonthDayFore { get; private set; }
+		public static Color MonthDayBack { get; private set; }
+		public static Color MonthTodayFore { get; private set; }
+		public static Color MonthTodayBack { get; private set; }
+
+
+		public static void InitializeTheme(ContainerControl container)
+		{
+			var provider = new SettingsProvider();
+			var theme = provider.Theme;
+			DarkMode = theme == ThemeMode.Dark ||
+				(theme == ThemeMode.System && Office.SystemDefaultDarkMode());
+
+			SetColors();
+
+			// true=dark, false=normal
+			var value = DarkMode;
+
+			DwmSetWindowAttribute(
+				container.Handle, DWMWA_USE_IMMERSIVE_DARK_MODE, ref value, Marshal.SizeOf(value));
+
+			// controls...
+
+			if (container is ThemedForm form)
+			{
+				form.OnThemeChange();
+			}
+			else if (container is ThemedUserControl control)
+			{
+				control.OnThemeChange();
+			}
+
+			container.BackColor = MonthHeader;
+			container.ForeColor = ForeColor;
+
+			Colorize(container.Controls);
+		}
+
+
+		private static void SetColors()
+		{
+			if (DarkMode)
+			{
+				// primary-dark = 202020 / 1F1F1F
+				// medium-dark  = 2B2B2B / 272727
+				// light-dark   = 363636 / 383838
+				// light purple = D2A1DF / D6A6D3
+				// dark purple  = 73356E (DarkOrchid)
+				// ---------------------------------------------------------
+
+				BackColor = ColorTranslator.FromHtml("#FF383838");
+				ForeColor = ColorTranslator.FromHtml("#FFE6E6E6");
+				Border = Color.DarkOrchid;
+				Control = Color.MediumOrchid;
+
+				// light purple (pink)
+				Highlight = ColorTranslator.FromHtml("#FFD2A1DF");
+
+				ButtonBack = ColorTranslator.FromHtml("#FF363636");
+				ButtonFore = ColorTranslator.FromHtml("#FFE6E6E6");
+				ButtonDisabled = Color.Gray;
+				ButtonBorder = ColorTranslator.FromHtml("#FF555555");
+				ButtonHotBack = ColorTranslator.FromHtml("#FF505050");
+				ButtonHotBorder = ColorTranslator.FromHtml("#FF808080");
+				ButtonPressBorder = Color.DarkOrchid;
+
+				LinkColor = Color.MediumOrchid;
+				HoverColor = Color.Orchid;
+
+				MonthHeader = ColorTranslator.FromHtml("#FF383838");
+				MonthPrimary = ColorTranslator.FromHtml("#FF1F1F1F");
+				MonthSecondary = ColorTranslator.FromHtml("#FF272727");
+				MonthGrid = ColorTranslator.FromHtml("#FF676767");
+				MonthDayFore = Color.LightGray;
+				MonthDayBack = ColorTranslator.FromHtml("#FF383838");
+				MonthTodayFore = Color.LightGray;
+				MonthTodayBack = ColorTranslator.FromHtml("#FF73356E"); // dark purpose
+
+				DetailOddBack = ColorTranslator.FromHtml("#FF1F1F1F");
+				DetailEvenBack = ColorTranslator.FromHtml("#FF272727");
+			}
+			else
+			{
+				BackColor = Color.White;
+				ForeColor = Color.Black;
+				Border = ColorTranslator.FromHtml("#FFD2A1DF");
+				Control = ColorTranslator.FromHtml("#FF73356E"); // dark purple
+
+				// light purple
+				Highlight = ColorTranslator.FromHtml("#FFBC58B6");
+
+				ButtonBack = ColorTranslator.FromHtml("#FFF7EDF7");
+				ButtonFore = ColorTranslator.FromHtml("#FF73356E"); // dark purple
+				ButtonDisabled = Color.Gray;
+				ButtonBorder = ColorTranslator.FromHtml("#FFF0DAEE");
+				ButtonHotBack = ColorTranslator.FromHtml("#FFF0DAEE");
+				ButtonHotBorder = ColorTranslator.FromHtml("#FF9E5499");
+				ButtonPressBorder = ColorTranslator.FromHtml("#FF9E5499");
+
+				LinkColor = ColorTranslator.FromHtml("#FF73356E"); // dark purple
+				HoverColor = Color.MediumOrchid;
+
+				MonthHeader = SystemColors.Control;
+				MonthPrimary = Color.White;
+				MonthSecondary = Color.WhiteSmoke;
+				MonthGrid = Color.DarkGray;
+				MonthDayFore = Color.Gray;
+				MonthDayBack = ColorTranslator.FromHtml("#FFF4E8F3");
+				MonthTodayFore = Color.Black;
+				MonthTodayBack = ColorTranslator.FromHtml("#FFD6A6D3");
+
+				DetailOddBack = ColorTranslator.FromHtml("#FFFDFAFE");
+				DetailEvenBack = Color.White;
+			}
+		}
+
+
+		private static void Colorize(Control.ControlCollection controls)
+		{
+			foreach (Control control in controls)
+			{
+				control.BackColor = BackColor;
+				control.ForeColor = ForeColor;
+
+				if (control.Controls.Count > 0)
+				{
+					Colorize(control.Controls);
+				}
+
+				if (control is ListView view)
+				{
+					foreach (ListViewItem item in view.Items)
+					{
+						item.BackColor = MonthHeader;
+						item.ForeColor = ForeColor;
+					}
+				}
+				else if (control is River.OneMoreAddIn.UI.MoreLinkLabel label)
+				{
+					label.LinkColor= LinkColor;
+					label.HoverColor= HoverColor;
+				}
+			}
+		}
+	}
+}
diff --git a/OneMoreCalendar/Things/ThemedForm.cs b/OneMoreCalendar/Things/ThemedForm.cs
new file mode 100644
index 0000000000..c3cfc33cd7
--- /dev/null
+++ b/OneMoreCalendar/Things/ThemedForm.cs
@@ -0,0 +1,36 @@
+//************************************************************************************************
+// Copyright © 2022 Steven M Cohn.  All rights reserved.
+//************************************************************************************************
+
+namespace OneMoreCalendar
+{
+	using System;
+	using System.Windows.Forms;
+
+
+	/// <summary>
+	/// Changes the theme of the current Form instance to Dark mode if the Windows
+	/// system default theme is also Dark mode.
+	/// </summary>
+	internal class ThemedForm : Form
+	{
+
+		protected bool StaticColors { get; set; }
+
+
+		protected override void OnLoad(EventArgs e)
+		{
+			base.OnLoad(e);
+
+			if (!StaticColors)
+			{
+				Theme.InitializeTheme(this);
+			}
+		}
+
+
+		public virtual void OnThemeChange()
+		{
+		}
+	}
+}
diff --git a/OneMoreCalendar/Things/ThemedUserControl.cs b/OneMoreCalendar/Things/ThemedUserControl.cs
new file mode 100644
index 0000000000..444c18a717
--- /dev/null
+++ b/OneMoreCalendar/Things/ThemedUserControl.cs
@@ -0,0 +1,29 @@
+//************************************************************************************************
+// Copyright © 2022 Steven M Cohn.  All rights reserved.
+//************************************************************************************************
+
+namespace OneMoreCalendar
+{
+	using System;
+	using System.Windows.Forms;
+
+
+	/// <summary>
+	/// Changes the theme of the current UserControl instance to Dark mode if the Windows
+	/// system default theme is also Dark mode.
+	/// </summary>
+	internal abstract class ThemedUserControl : UserControl
+	{
+		protected override void OnLoad(EventArgs e)
+		{
+			base.OnLoad(e);
+
+			Theme.InitializeTheme(this);
+		}
+
+
+		public virtual void OnThemeChange()
+		{
+		}
+	}
+}
diff --git a/OneMoreCalendar/YearsForm.Designer.cs b/OneMoreCalendar/YearsForm.Designer.cs
index 6adc22c302..d71fc3f811 100644
--- a/OneMoreCalendar/YearsForm.Designer.cs
+++ b/OneMoreCalendar/YearsForm.Designer.cs
@@ -40,12 +40,12 @@ private void InitializeComponent()
 			this.listView.ForeColor = System.Drawing.Color.FromArgb(((int)(((byte)(115)))), ((int)(((byte)(53)))), ((int)(((byte)(110)))));
 			this.listView.HeaderStyle = System.Windows.Forms.ColumnHeaderStyle.None;
 			this.listView.HideSelection = false;
-			this.listView.Location = new System.Drawing.Point(7, 9);
+			this.listView.Location = new System.Drawing.Point(4, 4);
 			this.listView.Margin = new System.Windows.Forms.Padding(0);
 			this.listView.MultiSelect = false;
 			this.listView.Name = "listView";
 			this.listView.OwnerDraw = true;
-			this.listView.Size = new System.Drawing.Size(370, 299);
+			this.listView.Size = new System.Drawing.Size(376, 309);
 			this.listView.TabIndex = 0;
 			this.listView.UseCompatibleStateImageBehavior = false;
 			this.listView.View = System.Windows.Forms.View.List;
@@ -68,7 +68,7 @@ private void InitializeComponent()
 			this.MaximizeBox = false;
 			this.MinimizeBox = false;
 			this.Name = "YearsForm";
-			this.Padding = new System.Windows.Forms.Padding(7, 9, 7, 9);
+			this.Padding = new System.Windows.Forms.Padding(4);
 			this.ShowIcon = false;
 			this.ShowInTaskbar = false;
 			this.StartPosition = System.Windows.Forms.FormStartPosition.Manual;
diff --git a/OneMoreCalendar/YearsForm.cs b/OneMoreCalendar/YearsForm.cs
index bfad0b7ff4..be3bc7cf79 100644
--- a/OneMoreCalendar/YearsForm.cs
+++ b/OneMoreCalendar/YearsForm.cs
@@ -19,7 +19,7 @@ internal partial class YearsForm : RoundedForm
 
 		private const int ItemRadius = 4;
 
-		private int skipYear; // exclude currently displayed year
+		private readonly int skipYear; // exclude currently displayed year
 		private ListViewItem hoveredItem;
 
 
@@ -58,12 +58,9 @@ protected override async void OnLoad(EventArgs e)
 				var years = await new OneNoteProvider()
 					.GetYears(await new SettingsProvider().GetNotebookIDs());
 
-				years.ToList().ForEach(y =>
+				years.Where(y => y != skipYear).ToList().ForEach(y =>
 				{
-					if (y != skipYear)
-					{
-						listView.Items.Add(y.ToString());
-					}
+					listView.Items.Add(y.ToString());
 				});
 			}
 		}
@@ -101,15 +98,20 @@ private void DrawItem(object sender, DrawListViewItemEventArgs e)
 				var size = e.Graphics.MeasureString(e.Item.Text, listView.Font);
 				var bounds = new Rectangle(e.Bounds.X, e.Bounds.Y, (int)size.Width + 8, e.Bounds.Height);
 
-				e.Graphics.FillRoundedRectangle(AppColors.HoverBrush, bounds, ItemRadius);
-				e.Graphics.DrawRoundedRectangle(AppColors.HoverPen, bounds, ItemRadius);
+				using var fill = new SolidBrush(Theme.ButtonBack);
+				e.Graphics.FillRoundedRectangle(fill, bounds, ItemRadius);
+
+				using var fore = new Pen(Theme.ButtonFore);
+				e.Graphics.DrawRoundedRectangle(fore, bounds, ItemRadius);
 			}
 			else
 			{
-				e.Graphics.FillRectangle(Brushes.White, e.Bounds);
+				using var backBrush = new SolidBrush(Theme.BackColor);
+				e.Graphics.FillRectangle(backBrush, e.Bounds);
 			}
 
-			e.Graphics.DrawString(e.Item.Text, listView.Font, AppColors.TextBrush, e.Bounds);
+			using var brush = new SolidBrush(Theme.Highlight);
+			e.Graphics.DrawString(e.Item.Text, listView.Font, brush, e.Bounds);
 		}