diff --git a/README.md b/README.md
index d41433d..64e30c0 100644
--- a/README.md
+++ b/README.md
@@ -234,6 +234,24 @@ sitting on. How close the radio has to be to a spot is one number per mode in
 `DigitalTuningToleranceHertz` — 300 Hz each out of the box, which is how N1MM
 keeps them and what it defaults them to.
 
+### Colours
+
+The callsign is coloured as it is typed, in N1MM's own colours: blue for a
+station worth working, red when it is new in one multiplier, green when it is
+new in more than one, grey for a dupe. A call under three characters stays blue.
+The same four colours paint a row in the log, a spot on the bandmap and a line
+in the check window, so the three windows cannot disagree.
+
+At the right-hand end of the callsign box is N1MM's mark: a tick when the call
+is in `MASTER.SCP`, a question mark while it is not. As in N1MM it only appears
+while the check window is open, for three characters or more.
+
+Two themes ship with the program. `light` is N1MM's own palette, down to the
+pale blue behind a window and the ivory on a button; `dark` is the same states
+in colours for a dark screen. Config ▸ Manage Skins, Colors and Fonts picks one,
+and the choice is kept in `settings.json` as `Theme`. Fonts and skins are not
+part of it: the name is N1MM's, the dialog only changes colours.
+
 ### Where the other station is
 
 Under the entry window is the line N1MM writes there: the beam heading, the
diff --git a/src/Nonemm.App/App.axaml b/src/Nonemm.App/App.axaml
index 76dc11b..4eb7fe3 100644
--- a/src/Nonemm.App/App.axaml
+++ b/src/Nonemm.App/App.axaml
@@ -1,11 +1,27 @@
 <Application xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="Nonemm.App.App"
-             RequestedThemeVariant="Default">
-             <!-- "Default" ThemeVariant follows system theme variant. "Dark" or "Light" are other available options. -->
+             RequestedThemeVariant="Light">
+    <!-- the colours behind these keys are filled in from the theme in use, in
+         App.ApplyTheme -->
+    <Application.Resources>
+        <SolidColorBrush x:Key="FormBackground">#CDDAEB</SolidColorBrush>
+        <SolidColorBrush x:Key="FormForeground">#000000</SolidColorBrush>
+        <SolidColorBrush x:Key="ButtonBackground">#FFFAF0</SolidColorBrush>
+        <SolidColorBrush x:Key="FieldBackground">#FFFFFF</SolidColorBrush>
+        <SolidColorBrush x:Key="FieldForeground">#000000</SolidColorBrush>
+    </Application.Resources>
 
     <Application.Styles>
         <FluentTheme />
         <StyleInclude Source="avares://Avalonia.Controls.DataGrid/Themes/Fluent.xaml" />
+
+        <Style Selector="Window">
+            <Setter Property="Background" Value="{DynamicResource FormBackground}" />
+            <Setter Property="Foreground" Value="{DynamicResource FormForeground}" />
+        </Style>
+        <Style Selector="Menu">
+            <Setter Property="Background" Value="{DynamicResource FormBackground}" />
+        </Style>
     </Application.Styles>
-</Application>
\ No newline at end of file
+</Application>
diff --git a/src/Nonemm.App/App.axaml.cs b/src/Nonemm.App/App.axaml.cs
index 45db542..d1c5a40 100644
--- a/src/Nonemm.App/App.axaml.cs
+++ b/src/Nonemm.App/App.axaml.cs
@@ -1,7 +1,9 @@
 using Avalonia;
 using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Markup.Xaml;
+using Avalonia.Media;
 using Nonemm.App.Configuration;
+using Nonemm.App.Theming;
 using Nonemm.App.Windows;
 
 namespace Nonemm.App;
@@ -16,10 +18,62 @@ public partial class App : Application
         {
             UserPaths paths = UserPaths.Default();
             paths.CreateFolders();
-            AppSession session = new(paths, Settings.Load(paths.SettingsFile));
+            Settings settings = Settings.Load(paths.SettingsFile);
+            Themes.Use(settings.Theme);
+            Themes.Changed += (_, _) => ApplyTheme();
+            ApplyTheme();
+            AppSession session = new(paths, settings);
             desktop.MainWindow = new EntryWindow(session);
             desktop.ShutdownRequested += (_, _) => session.Dispose();
         }
         base.OnFrameworkInitializationCompleted();
     }
+
+    /// The window chrome follows the theme through these resources; everything
+    /// that draws a station or a spot asks `Themes.Current` as it paints.
+    private void ApplyTheme()
+    {
+        Theme theme = Themes.Current;
+        RequestedThemeVariant = theme.Variant;
+        Set("FormBackground", theme.FormBackground);
+        Set("FormForeground", theme.FormForeground);
+        Set("FieldBackground", theme.FieldBackground);
+        Set("FieldForeground", theme.FieldForeground);
+        // the keys the Fluent controls read, so a text box and a button take
+        // the theme's colours in every state rather than only where a style of
+        // ours reaches them
+        foreach (string key in new[]
+        {
+            "TextControlBackground", "TextControlBackgroundPointerOver",
+            "TextControlBackgroundFocused", "TextControlBackgroundDisabled",
+            "ComboBoxBackground", "ComboBoxBackgroundPointerOver", "ComboBoxBackgroundPressed",
+            "DataGridRowBackgroundBrush",
+        })
+        {
+            Set(key, theme.FieldBackground);
+        }
+        foreach (string key in new[]
+        {
+            "TextControlForeground", "TextControlForegroundPointerOver",
+            "TextControlForegroundFocused", "ComboBoxForeground", "ButtonForeground",
+            "ButtonForegroundPointerOver", "ButtonForegroundPressed",
+        })
+        {
+            Set(key, theme.FieldForeground);
+        }
+        Set("ButtonBackground", theme.ButtonBackground);
+        Set("ButtonBackgroundPointerOver", Lighter(theme.ButtonBackground));
+        Set("ButtonBackgroundPressed", Darker(theme.ButtonBackground));
+    }
+
+    private void Set(string key, Color colour) => Resources[key] = new SolidColorBrush(colour);
+
+    private static Color Lighter(Color colour) => Shifted(colour, 12);
+
+    private static Color Darker(Color colour) => Shifted(colour, -18);
+
+    private static Color Shifted(Color colour, int by) => Color.FromRgb(
+        (byte)Math.Clamp(colour.R + by, 0, 255),
+        (byte)Math.Clamp(colour.G + by, 0, 255),
+        (byte)Math.Clamp(colour.B + by, 0, 255));
 }
diff --git a/src/Nonemm.App/Configuration/Settings.cs b/src/Nonemm.App/Configuration/Settings.cs
index 0072257..dfbd63d 100644
--- a/src/Nonemm.App/Configuration/Settings.cs
+++ b/src/Nonemm.App/Configuration/Settings.cs
@@ -9,6 +9,10 @@ public sealed record Settings
 {
     public string DatabasePath { get; init; } = "";
 
+    /// `light` is N1MM's own palette, `dark` the same states in colours for a
+    /// dark screen. Config > Manage Skins, Colors and Fonts picks one.
+    public string Theme { get; init; } = "light";
+
     public int ContestNumber { get; init; }
 
     public StoredStation Station { get; init; } = new();
diff --git a/src/Nonemm.App/Dialogs/MessagesDialog.axaml.cs b/src/Nonemm.App/Dialogs/MessagesDialog.axaml.cs
index fde043c..a5ecc59 100644
--- a/src/Nonemm.App/Dialogs/MessagesDialog.axaml.cs
+++ b/src/Nonemm.App/Dialogs/MessagesDialog.axaml.cs
@@ -3,6 +3,7 @@ using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Media;
 using Avalonia.Platform.Storage;
+using Nonemm.App.Theming;
 using Nonemm.Core;
 using Nonemm.Session;
 
@@ -22,13 +23,13 @@ public sealed partial class MessagesDialog : Window
 
     /// The three banks of function keys, coloured so the editor shows which
     /// line is which key.
-    private static readonly IBrush Blue = new SolidColorBrush(Color.FromRgb(0x29, 0x80, 0xB9));
+    private static IBrush Blue => Themes.Brush(Themes.Current.Worth);
 
-    private static readonly IBrush Green = new SolidColorBrush(Color.FromRgb(0x27, 0xAE, 0x60));
+    private static IBrush Green => Themes.Brush(Themes.Current.Multipliers);
 
-    private static readonly IBrush Red = new SolidColorBrush(Color.FromRgb(0xC0, 0x39, 0x2B));
+    private static IBrush Red => Themes.Brush(Themes.Current.Multiplier);
 
-    private static readonly IBrush Grey = new SolidColorBrush(Color.FromRgb(0x7F, 0x8C, 0x8D));
+    private static IBrush Grey => Themes.Brush(Themes.Current.Dupe);
 
     private readonly ModeCategory mode;
 
diff --git a/src/Nonemm.App/Dialogs/ThemeDialog.axaml b/src/Nonemm.App/Dialogs/ThemeDialog.axaml
new file mode 100644
index 0000000..fa0ec62
--- /dev/null
+++ b/src/Nonemm.App/Dialogs/ThemeDialog.axaml
@@ -0,0 +1,27 @@
+<Window xmlns="https://github.com/avaloniaui"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        x:Class="Nonemm.App.Dialogs.ThemeDialog"
+        Title="Colors" Width="360" SizeToContent="Height"
+        WindowStartupLocation="CenterOwner" CanResize="False">
+  <DockPanel Margin="14">
+    <StackPanel DockPanel.Dock="Bottom" Orientation="Horizontal" HorizontalAlignment="Center"
+                Spacing="30" Margin="0,14,0,0">
+      <Button Content="Ok" Width="85" HorizontalContentAlignment="Center"
+              Click="OnOk" IsDefault="True" />
+      <Button Content="Cancel" Width="85" HorizontalContentAlignment="Center"
+              Click="OnCancel" IsCancel="True" />
+    </StackPanel>
+    <StackPanel Spacing="8">
+      <TextBlock Text="Colors" FontSize="11" />
+      <ComboBox Name="ThemeBox" HorizontalAlignment="Stretch" SelectionChanged="OnPicked" />
+      <TextBlock Name="AboutText" FontSize="11" TextWrapping="Wrap" />
+      <ItemsControl Name="Swatches" Margin="0,4,0,0">
+        <ItemsControl.ItemsPanel>
+          <ItemsPanelTemplate>
+            <WrapPanel />
+          </ItemsPanelTemplate>
+        </ItemsControl.ItemsPanel>
+      </ItemsControl>
+    </StackPanel>
+  </DockPanel>
+</Window>
diff --git a/src/Nonemm.App/Dialogs/ThemeDialog.axaml.cs b/src/Nonemm.App/Dialogs/ThemeDialog.axaml.cs
new file mode 100644
index 0000000..26d6ddc
--- /dev/null
+++ b/src/Nonemm.App/Dialogs/ThemeDialog.axaml.cs
@@ -0,0 +1,65 @@
+using Avalonia.Controls;
+using Avalonia.Interactivity;
+using Avalonia.Layout;
+using Avalonia.Media;
+using Nonemm.App.Theming;
+
+namespace Nonemm.App.Dialogs;
+
+/// Which colours the program paints with. N1MM keeps skins, colours and fonts
+/// in one place; this picks between the themes that ship with the program and
+/// shows what each one paints a station.
+public sealed partial class ThemeDialog : Window
+{
+    public ThemeDialog(string current)
+    {
+        InitializeComponent();
+        ThemeBox.ItemsSource = Themes.All.Select(Label).ToList();
+        ThemeBox.SelectedIndex = Math.Max(0, Themes.All.ToList().FindIndex(t => t.Name == Themes.Find(current).Name));
+    }
+
+    private Theme Picked => Themes.All[Math.Max(0, ThemeBox.SelectedIndex)];
+
+    private static string Label(Theme theme) => theme.Name switch
+    {
+        "light" => "Light — N1MM's own colours",
+        "dark" => "Dark — for operating at night",
+        _ => theme.Name,
+    };
+
+    private void OnPicked(object? sender, SelectionChangedEventArgs e) => ShowSwatches();
+
+    private void ShowSwatches()
+    {
+        Theme theme = Picked;
+        AboutText.Text = "What a station is painted in the callsign box, left to right: worth " +
+                         "working, one new multiplier, more than one, a dupe.";
+        Swatches.ItemsSource = new[]
+        {
+            Swatch(theme.Worth, theme.FieldBackground),
+            Swatch(theme.Multiplier, theme.FieldBackground),
+            Swatch(theme.Multipliers, theme.FieldBackground),
+            Swatch(theme.Dupe, theme.FieldBackground),
+        };
+    }
+
+    private static Border Swatch(Color text, Color background) => new()
+    {
+        Background = new SolidColorBrush(background),
+        Width = 66,
+        Height = 26,
+        Margin = new Avalonia.Thickness(0, 0, 6, 6),
+        Child = new TextBlock
+        {
+            Text = "OM3KFF",
+            FontSize = 11,
+            Foreground = new SolidColorBrush(text),
+            HorizontalAlignment = HorizontalAlignment.Center,
+            VerticalAlignment = VerticalAlignment.Center,
+        },
+    };
+
+    private void OnOk(object? sender, RoutedEventArgs e) => Close(Picked.Name);
+
+    private void OnCancel(object? sender, RoutedEventArgs e) => Close(null);
+}
diff --git a/src/Nonemm.App/Theming/Theme.cs b/src/Nonemm.App/Theming/Theme.cs
new file mode 100644
index 0000000..95b787c
--- /dev/null
+++ b/src/Nonemm.App/Theming/Theme.cs
@@ -0,0 +1,132 @@
+using Avalonia.Media;
+using Avalonia.Styling;
+
+namespace Nonemm.App.Theming;
+
+/// The colours one theme paints with. The names follow N1MM's
+/// `ApplicationStyles`, because the light theme is N1MM's own palette and the
+/// windows are laid out the same way.
+public sealed record Theme
+{
+    public required string Name { get; init; }
+
+    /// Which set of control colours the theme sits on, so a text box or a
+    /// scroll bar looks right under the colours above.
+    public required ThemeVariant Variant { get; init; }
+
+    /// Behind a window, and the text on it.
+    public required Color FormBackground { get; init; }
+
+    public required Color FormForeground { get; init; }
+
+    public required Color ButtonBackground { get; init; }
+
+    /// Inside an entry box or a dialog box, and the text in it.
+    public required Color FieldBackground { get; init; }
+
+    public required Color FieldForeground { get; init; }
+
+    /// A log row, and every second one.
+    public required Color GridBackground { get; init; }
+
+    public required Color GridAlternateBackground { get; init; }
+
+    /// Worth a contact, no new multiplier.
+    public required Color Worth { get; init; }
+
+    public required Color WorthBackground { get; init; }
+
+    /// New in one multiplier.
+    public required Color Multiplier { get; init; }
+
+    public required Color MultiplierBackground { get; init; }
+
+    /// New in more than one.
+    public required Color Multipliers { get; init; }
+
+    public required Color MultipliersBackground { get; init; }
+
+    public required Color Dupe { get; init; }
+
+    public required Color DupeBackground { get; init; }
+
+    /// The frequency we are calling CQ on.
+    public required Color Cq { get; init; }
+
+    /// Behind a line that is in the log, one that is not filled in yet, and one
+    /// that cannot be read.
+    public required Color GoodBackground { get; init; }
+
+    public required Color EmptyBackground { get; init; }
+
+    public required Color BadBackground { get; init; }
+
+    /// The boxes while quick editing a logged contact.
+    public required Color QuickEdit { get; init; }
+
+    /// The light that says a radio is answering, and the one that says
+    /// something is going out on the air.
+    public required Color RadioLight { get; init; }
+
+    public required Color TransmitLight { get; init; }
+
+    /// N1MM's own defaults, from `ApplicationStyles`: the program as it looks
+    /// on a fresh install.
+    public static readonly Theme Light = new()
+    {
+        Name = "light",
+        Variant = ThemeVariant.Light,
+        FormBackground = Color.FromRgb(0xCD, 0xDA, 0xEB),
+        FormForeground = Color.FromRgb(0x00, 0x00, 0x00),
+        ButtonBackground = Color.FromRgb(0xFF, 0xFA, 0xF0),
+        FieldBackground = Color.FromRgb(0xFF, 0xFF, 0xFF),
+        FieldForeground = Color.FromRgb(0x00, 0x00, 0x00),
+        GridBackground = Color.FromRgb(0xF2, 0xFC, 0xFF),
+        GridAlternateBackground = Color.FromRgb(0xAB, 0xC0, 0xDC),
+        Worth = Color.FromRgb(0x00, 0x00, 0xFF),
+        WorthBackground = Color.FromRgb(0x51, 0xA8, 0xFF),
+        Multiplier = Color.FromRgb(0xE8, 0x00, 0x00),
+        MultiplierBackground = Color.FromRgb(0xFF, 0x37, 0x37),
+        Multipliers = Color.FromRgb(0x0D, 0x9D, 0x0D),
+        MultipliersBackground = Color.FromRgb(0x5F, 0xF1, 0x5F),
+        Dupe = Color.FromRgb(0x80, 0x80, 0x80),
+        DupeBackground = Color.FromRgb(0xD4, 0xD4, 0xD4),
+        Cq = Color.FromRgb(0xFF, 0x00, 0x00),
+        GoodBackground = Color.FromRgb(0xD4, 0xF5, 0xD4),
+        EmptyBackground = Color.FromRgb(0xFF, 0xE4, 0xE1),
+        BadBackground = Color.FromRgb(0xFF, 0xF8, 0xC4),
+        QuickEdit = Color.FromRgb(0xFF, 0xFF, 0xC0),
+        RadioLight = Color.FromRgb(0x0D, 0x9D, 0x0D),
+        TransmitLight = Color.FromRgb(0xFF, 0x00, 0x00),
+    };
+
+    /// For operating at night: the same states, in colours that carry on a dark
+    /// background.
+    public static readonly Theme Dark = new()
+    {
+        Name = "dark",
+        Variant = ThemeVariant.Dark,
+        FormBackground = Color.FromRgb(0x20, 0x22, 0x25),
+        FormForeground = Color.FromRgb(0xE8, 0xE8, 0xE8),
+        ButtonBackground = Color.FromRgb(0x2E, 0x31, 0x35),
+        FieldBackground = Color.FromRgb(0x17, 0x19, 0x1B),
+        FieldForeground = Color.FromRgb(0xE8, 0xE8, 0xE8),
+        GridBackground = Color.FromRgb(0x1B, 0x1D, 0x20),
+        GridAlternateBackground = Color.FromRgb(0x23, 0x26, 0x2A),
+        Worth = Color.FromRgb(0x29, 0x80, 0xB9),
+        WorthBackground = Color.FromRgb(0x1F, 0x4E, 0x6E),
+        Multiplier = Color.FromRgb(0xC0, 0x39, 0x2B),
+        MultiplierBackground = Color.FromRgb(0x6E, 0x24, 0x1C),
+        Multipliers = Color.FromRgb(0x27, 0xAE, 0x60),
+        MultipliersBackground = Color.FromRgb(0x1B, 0x5E, 0x36),
+        Dupe = Color.FromRgb(0x7F, 0x8C, 0x8D),
+        DupeBackground = Color.FromRgb(0x3A, 0x40, 0x40),
+        Cq = Color.FromRgb(0xE7, 0x4C, 0x3C),
+        GoodBackground = Color.FromRgb(0x1E, 0x38, 0x24),
+        EmptyBackground = Color.FromRgb(0x3A, 0x24, 0x24),
+        BadBackground = Color.FromRgb(0x3C, 0x36, 0x1C),
+        QuickEdit = Color.FromRgb(0x4A, 0x44, 0x1E),
+        RadioLight = Color.FromRgb(0x27, 0xAE, 0x60),
+        TransmitLight = Color.FromRgb(0xC0, 0x39, 0x2B),
+    };
+}
diff --git a/src/Nonemm.App/Theming/Themes.cs b/src/Nonemm.App/Theming/Themes.cs
new file mode 100644
index 0000000..8b314c2
--- /dev/null
+++ b/src/Nonemm.App/Theming/Themes.cs
@@ -0,0 +1,46 @@
+using Avalonia.Media;
+
+namespace Nonemm.App.Theming;
+
+/// Which theme the program is painting with. Everything that draws a colour
+/// asks here rather than holding a brush of its own, so changing the theme
+/// changes every window.
+public static class Themes
+{
+    public static readonly IReadOnlyList<Theme> All = [Theme.Light, Theme.Dark];
+
+    private static readonly Dictionary<Color, IBrush> brushes = [];
+
+    public static Theme Current { get; private set; } = Theme.Light;
+
+    /// Raised after the theme changes, for the windows that paint what they
+    /// hold rather than rebuilding it.
+    public static event EventHandler? Changed;
+
+    public static Theme Find(string name) =>
+        All.FirstOrDefault(t => string.Equals(t.Name, name, StringComparison.OrdinalIgnoreCase))
+        ?? Theme.Light;
+
+    public static void Use(string name)
+    {
+        Theme wanted = Find(name);
+        if (wanted == Current)
+        {
+            return;
+        }
+        Current = wanted;
+        Changed?.Invoke(null, EventArgs.Empty);
+    }
+
+    /// One brush per colour, because a brush is created for every row of every
+    /// window that is painted.
+    public static IBrush Brush(Color colour)
+    {
+        if (!brushes.TryGetValue(colour, out IBrush? brush))
+        {
+            brush = new SolidColorBrush(colour);
+            brushes[colour] = brush;
+        }
+        return brush;
+    }
+}
diff --git a/src/Nonemm.App/Verdicts.cs b/src/Nonemm.App/Verdicts.cs
index d6b062e..cd6e978 100644
--- a/src/Nonemm.App/Verdicts.cs
+++ b/src/Nonemm.App/Verdicts.cs
@@ -1,31 +1,28 @@
 using Avalonia.Media;
+using Nonemm.App.Theming;
 using Nonemm.Contests;
 
 namespace Nonemm.App;
 
 /// One place decides what colour a station is, so the callsign box, the frame
 /// above it, a row in the check window and a spot on the bandmap cannot
-/// disagree. The colours are N1MM's own defaults, from ApplicationStyles:
-/// QColor, MultColor, MultiMultColor and DupeColor.
+/// disagree. The colours come from the theme in use.
 public static class Verdicts
 {
-    /// Worth a contact but no new multiplier.
-    public static readonly IBrush Worth = new SolidColorBrush(Color.FromRgb(0x00, 0x00, 0xFF));
+    public static IBrush Worth => Themes.Brush(Themes.Current.Worth);
 
-    /// New in one multiplier.
-    public static readonly IBrush NewMultiplier = new SolidColorBrush(Color.FromRgb(0xE8, 0x00, 0x00));
+    public static IBrush NewMultiplier => Themes.Brush(Themes.Current.Multiplier);
 
-    /// New in more than one, which is worth turning the radio for.
-    public static readonly IBrush NewMultipliers = new SolidColorBrush(Color.FromRgb(0x0D, 0x9D, 0x0D));
+    public static IBrush NewMultipliers => Themes.Brush(Themes.Current.Multipliers);
 
-    public static readonly IBrush Dupe = new SolidColorBrush(Color.FromRgb(0x80, 0x80, 0x80));
+    public static IBrush Dupe => Themes.Brush(Themes.Current.Dupe);
 
-    public static readonly IBrush Nothing = Dupe;
+    public static IBrush Nothing => Dupe;
 
     /// The frequency we are calling CQ on.
-    public static readonly IBrush Cq = new SolidColorBrush(Color.FromRgb(0xFF, 0x00, 0x00));
+    public static IBrush Cq => Themes.Brush(Themes.Current.Cq);
 
-    /// Nothing typed yet is the same blue as a station worth working: that is
+    /// Nothing typed yet is the same colour as a station worth working: that is
     /// what N1MM leaves the callsign box.
     public static IBrush Colour(Verdict? verdict) =>
         verdict is null ? Worth
@@ -35,18 +32,13 @@ public static class Verdicts
         : Worth;
 
     /// The same four states as backgrounds, which is what N1MM paints behind a
-    /// spot: QBackColor, MultBackColor and DupeBackColor.
+    /// spot.
     public static IBrush Background(Verdict? verdict) =>
-        verdict is null ? WorthBack
-        : verdict.IsDupe ? DupeBack
-        : verdict.NewMultipliers.Count > 0 ? MultiplierBack
-        : WorthBack;
-
-    private static readonly IBrush WorthBack = new SolidColorBrush(Color.FromRgb(0x51, 0xA8, 0xFF));
-
-    private static readonly IBrush MultiplierBack = new SolidColorBrush(Color.FromRgb(0xFF, 0x37, 0x37));
-
-    private static readonly IBrush DupeBack = new SolidColorBrush(Color.FromRgb(0xD4, 0xD4, 0xD4));
+        verdict is null ? Themes.Brush(Themes.Current.WorthBackground)
+        : verdict.IsDupe ? Themes.Brush(Themes.Current.DupeBackground)
+        : verdict.NewMultipliers.Count > 1 ? Themes.Brush(Themes.Current.MultipliersBackground)
+        : verdict.NewMultipliers.Count == 1 ? Themes.Brush(Themes.Current.MultiplierBackground)
+        : Themes.Brush(Themes.Current.WorthBackground);
 
     public static string Describe(Verdict? verdict)
     {
diff --git a/src/Nonemm.App/Windows/EntryWindow.Menu.cs b/src/Nonemm.App/Windows/EntryWindow.Menu.cs
index ef8cbdc..27d0845 100644
--- a/src/Nonemm.App/Windows/EntryWindow.Menu.cs
+++ b/src/Nonemm.App/Windows/EntryWindow.Menu.cs
@@ -3,6 +3,7 @@ using Avalonia.Interactivity;
 using Avalonia.Platform.Storage;
 using Nonemm.App.Configuration;
 using Nonemm.App.Dialogs;
+using Nonemm.App.Theming;
 using Nonemm.Contests;
 using Nonemm.Core;
 using Nonemm.Core.Country;
@@ -469,6 +470,18 @@ public sealed partial class EntryWindow
 
     private void OnEditPhoneMessages(object? sender, RoutedEventArgs e) => _ = EditMessages(ModeCategory.Phone);
 
+    private async void OnThemeSettings(object? sender, RoutedEventArgs e)
+    {
+        ThemeDialog dialog = new(session.Settings.Theme);
+        if (await dialog.ShowDialog<string?>(this) is not { } picked)
+        {
+            return;
+        }
+        session.Save(session.Settings with { Theme = picked });
+        Themes.Use(picked);
+        Status($"{picked} colours");
+    }
+
     private async void OnQtcSetup(object? sender, RoutedEventArgs e)
     {
         QtcSetupDialog dialog = new(session.Settings);
diff --git a/src/Nonemm.App/Windows/EntryWindow.axaml b/src/Nonemm.App/Windows/EntryWindow.axaml
index 4ea1e8a..a6e9a08 100644
--- a/src/Nonemm.App/Windows/EntryWindow.axaml
+++ b/src/Nonemm.App/Windows/EntryWindow.axaml
@@ -118,6 +118,7 @@
           <MenuItem Header="Change _SSB Function Key Definitions" Click="OnEditPhoneMessages" />
         </MenuItem>
         <MenuItem Header="Change Band Plan…" Click="OnSubBandSettings" />
+        <MenuItem Header="Manage Skins, Colors and Fonts…" Click="OnThemeSettings" />
         <MenuItem Header="Edit Networked-Computer Names…" Click="OnNetworkSettings" />
         <MenuItem Header="WAE">
           <MenuItem Header="Open QTC Window setup area" Click="OnQtcSetup" />
diff --git a/src/Nonemm.App/Windows/EntryWindow.axaml.cs b/src/Nonemm.App/Windows/EntryWindow.axaml.cs
index e1b7dd5..2dc51e4 100644
--- a/src/Nonemm.App/Windows/EntryWindow.axaml.cs
+++ b/src/Nonemm.App/Windows/EntryWindow.axaml.cs
@@ -7,6 +7,7 @@ using Avalonia.Media;
 using Avalonia.Threading;
 using Nonemm.Contests;
 using Nonemm.Core;
+using Nonemm.App.Theming;
 using Nonemm.Session;
 
 namespace Nonemm.App.Windows;
@@ -24,13 +25,6 @@ public sealed partial class EntryWindow : Window
 
     private static readonly IBrush Dark = new SolidColorBrush(Color.FromArgb(0x33, 0x80, 0x80, 0x80));
 
-    private static readonly IBrush GreenLight = new SolidColorBrush(Color.FromRgb(0x0D, 0x9D, 0x0D));
-
-    private static readonly IBrush RedLight = new SolidColorBrush(Color.FromRgb(0xFF, 0x00, 0x00));
-
-    /// The pale yellow N1MM paints the entry boxes while quick editing.
-    private static readonly IBrush QuickEditBackground = new SolidColorBrush(Color.FromRgb(0xFF, 0xFF, 0xC0));
-
     private bool sending;
     private TextBlock? callMark;
     private TextBox? nameBox;
@@ -52,6 +46,8 @@ public sealed partial class EntryWindow : Window
             BuildEntryBoxes();
             ShowSecondRadio();
         });
+        Themes.Changed += OnThemeChanged;
+        Closed += (_, _) => Themes.Changed -= OnThemeChanged;
         clock.Tick += (_, _) => UpdateClock();
         clock.Start();
         session.ActiveRadioChanged += (_, number) =>
@@ -67,6 +63,8 @@ public sealed partial class EntryWindow : Window
     }
 
 
+    private void OnThemeChanged(object? sender, EventArgs e) => Dispatcher.UIThread.Post(Refresh);
+
     /// Resolved every time rather than held, because opening a contest builds
     /// new positions.
     private OperatingPosition? Logging =>
@@ -697,8 +695,8 @@ public sealed partial class EntryWindow : Window
             }
             else
             {
-                box.Background = QuickEditBackground;
-                box.Foreground = Brushes.Black;
+                box.Background = Themes.Brush(Themes.Current.QuickEdit);
+                box.Foreground = Themes.Brush(Themes.Current.FormForeground);
             }
         }
         FrequencyText.Text = Logging.TransmitFrequency.Hertz > 0
@@ -719,7 +717,7 @@ public sealed partial class EntryWindow : Window
         ShowCallColour(verdict);
         VerdictBorder.Background = Verdicts.Background(verdict);
         VerdictText.Text = VerdictLine(verdict);
-        VerdictText.Foreground = Brushes.Black;
+        VerdictText.Foreground = Themes.Brush(Themes.Current.FormForeground);
         foreach (Window window in openWindows.Values)
         {
             (window as RefreshableWindow)?.Refresh();
@@ -781,8 +779,8 @@ public sealed partial class EntryWindow : Window
     private void ShowLights()
     {
         bool radio = session.Radios.Any(r => r.Number == radioNumber && r.IsConnected);
-        RadioLight.Fill = radio ? GreenLight : Dark;
-        TransmitLight.Fill = sending ? RedLight : Dark;
+        RadioLight.Fill = radio ? Themes.Brush(Themes.Current.RadioLight) : Dark;
+        TransmitLight.Fill = sending ? Themes.Brush(Themes.Current.TransmitLight) : Dark;
     }
 
     /// What N1MM writes in its title bar: the frequency, the mode, whether the
diff --git a/src/Nonemm.App/Windows/QtcWindow.axaml.cs b/src/Nonemm.App/Windows/QtcWindow.axaml.cs
index 2010322..3cc1b53 100644
--- a/src/Nonemm.App/Windows/QtcWindow.axaml.cs
+++ b/src/Nonemm.App/Windows/QtcWindow.axaml.cs
@@ -5,6 +5,7 @@ using Avalonia.Media;
 using Nonemm.App.Configuration;
 using Nonemm.App.Dialogs;
 using Nonemm.Contests.Rules;
+using Nonemm.App.Theming;
 using Nonemm.Core;
 using Nonemm.Session;
 
@@ -20,9 +21,11 @@ namespace Nonemm.App.Windows;
 /// SSB by voice, on RTTY from the digital window there is not yet.
 public sealed partial class QtcWindow : Window
 {
-    private static readonly IBrush Saved = new SolidColorBrush(Color.FromRgb(0xD4, 0xF5, 0xD4));
-    private static readonly IBrush Unsaved = new SolidColorBrush(Color.FromRgb(0xFF, 0xE4, 0xE1));
-    private static readonly IBrush Malformed = new SolidColorBrush(Color.FromRgb(0xFF, 0xF8, 0xC4));
+    private static IBrush Saved => Themes.Brush(Themes.Current.GoodBackground);
+
+    private static IBrush Unsaved => Themes.Brush(Themes.Current.EmptyBackground);
+
+    private static IBrush Malformed => Themes.Brush(Themes.Current.BadBackground);
 
     private readonly AppSession session;
     private readonly OperatingPosition position;
diff --git a/src/Nonemm.App/Windows/TelnetWindow.axaml.cs b/src/Nonemm.App/Windows/TelnetWindow.axaml.cs
index 25b7769..36729db 100644
--- a/src/Nonemm.App/Windows/TelnetWindow.axaml.cs
+++ b/src/Nonemm.App/Windows/TelnetWindow.axaml.cs
@@ -5,6 +5,7 @@ using Avalonia.Interactivity;
 using Avalonia.Media;
 using Avalonia.Threading;
 using Nonemm.App.Configuration;
+using Nonemm.App.Theming;
 using Nonemm.Core;
 using Nonemm.Session;
 using Nonemm.Spotting;
@@ -18,9 +19,11 @@ public sealed partial class TelnetWindow : RefreshableWindow
 {
     private const int LinesKept = 500;
 
-    private static readonly IBrush SpotColour = new SolidColorBrush(Color.FromRgb(0x27, 0xAE, 0x60));
-    private static readonly IBrush SentColour = new SolidColorBrush(Color.FromRgb(0x29, 0x80, 0xB9));
-    private static readonly IBrush NoticeColour = new SolidColorBrush(Color.FromRgb(0x7F, 0x8C, 0x8D));
+    private static IBrush SpotColour => Themes.Brush(Themes.Current.Multipliers);
+
+    private static IBrush SentColour => Themes.Brush(Themes.Current.Worth);
+
+    private static IBrush NoticeColour => Themes.Brush(Themes.Current.Dupe);
 
     private readonly AppSession session;
     private readonly Action<Frequency, string> tune;
diff --git a/tests/Nonemm.App.Tests/ThemesTests.cs b/tests/Nonemm.App.Tests/ThemesTests.cs
new file mode 100644
index 0000000..8ee8a0f
--- /dev/null
+++ b/tests/Nonemm.App.Tests/ThemesTests.cs
@@ -0,0 +1,30 @@
+using Nonemm.App.Theming;
+
+namespace Nonemm.App.Tests;
+
+public class ThemesTests
+{
+    [Fact]
+    public void TheThemesAreFoundByName()
+    {
+        Assert.Equal("light", Themes.Find("light").Name);
+        Assert.Equal("dark", Themes.Find("DARK").Name);
+    }
+
+    [Fact]
+    public void AThemeNobodyShipsFallsBackToTheN1mmColours() =>
+        Assert.Equal(Theme.Light, Themes.Find("solarized"));
+
+    [Fact]
+    public void OneBrushIsHandedOutPerColour() =>
+        Assert.Same(Themes.Brush(Theme.Light.Worth), Themes.Brush(Theme.Light.Worth));
+
+    [Fact]
+    public void EveryThemePaintsTheFourStatesApart()
+    {
+        foreach (Theme theme in Themes.All)
+        {
+            Assert.Equal(4, new[] { theme.Worth, theme.Multiplier, theme.Multipliers, theme.Dupe }.Distinct().Count());
+        }
+    }
+}