feat(ui): make Blueprint the default color scheme

- Add the Blueprint scheme: navy canvas, pale blue sheet, dark navy part
  outlines, orange-red rapids and twelve distinct, readable part fills.
- Use it as the settings default and the fallback for unknown scheme names,
  and list it first in Options. Saved scheme choices are kept.
- Run the palette spacing and readability tests over Blueprint and Classic.
- Document the default in nesting-view-colors.md.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

OpenNest.WinForms.Tests/ClassicPaletteTests.cs

@@ -38,23 +38,28 @@ public class ClassicPaletteTests
         return System.Math.Sqrt((l1 - l2) * (l1 - l2) + (a1 - a2) * (a1 - a2) + (b1 - b2) * (b1 - b2));
     }
 
-    [Fact]
-    public void ClassicFillsAreClearlyDistinctFromEachOther()
+    public static TheoryData<string> ListedPalettes => new() { "Blueprint", "Classic" };
+
+    [Theory]
+    [MemberData(nameof(ListedPalettes))]
+    public void FillsAreClearlyDistinctFromEachOther(string name)
     {
-        var colors = ColorSchemeRegistry.Get("Classic").PartColors;
+        var colors = ColorSchemeRegistry.Get(name).PartColors;
         Assert.Equal(12, colors.Length);
         for (var i = 0; i < colors.Length; i++)
         {
             for (var j = i + 1; j < colors.Length; j++)
                 Assert.True(DeltaE(colors[i], colors[j]) >= 30,
-                    $"Classic colors {i} and {j} are too similar ({DeltaE(colors[i], colors[j]):F1}).");
+                    $"{name} colors {i} and {j} are too similar ({DeltaE(colors[i], colors[j]):F1}).");
         }
     }
 
-    [Fact]
-    public void ClassicFillsStayReadableAndClearOfEtchGreenAndTheSheet()
+    [Theory]
+    [MemberData(nameof(ListedPalettes))]
+    public void FillsStayReadableAndClearOfEtchGreenAndTheSheet(string name)
     {
-        var scheme = ColorSchemeRegistry.Get("Classic");
+        var scheme = ColorSchemeRegistry.Get(name);
+        Assert.Equal(name, scheme.Name);
         Assert.All(scheme.PartColors, color =>
         {
             Assert.True(Contrast(color, Color.Black) >= 4.5, $"{color} is too dark for black part IDs.");

OpenNest.WinForms.Tests/FestiveColorSchemeTests.cs

@@ -30,7 +30,7 @@ public class FestiveColorSchemeTests
     }
 
     [Fact]
-    public void FestiveSchemesRoundTripAndLeaveClassicAsDefault()
+    public void FestiveSchemesRoundTripAndLeaveBlueprintAsDefault()
     {
         foreach (var name in new[] { "Halloween", "Christmas", "4th of July" })
         {
@@ -41,7 +41,7 @@ public class FestiveColorSchemeTests
             Assert.Equal(scheme.PartColors.Select(c => c.ToArgb()), restored.PartColors.Select(c => c.ToArgb()));
         }
 
-        Assert.Equal("Classic", ColorSchemeRegistry.Get(null).Name);
+        Assert.Equal("Blueprint", ColorSchemeRegistry.Get(null).Name);
     }
 
     private static double Distance(Color a, Color b)

OpenNest/ColorSchemeRegistry.cs

@@ -15,6 +15,7 @@ namespace OpenNest
             StringComparer.OrdinalIgnoreCase
         )
         {
+            ["Blueprint"] = BuildBlueprint(),
             ["Classic"] = BuildClassic(),
             ["Pastel"] = BuildPastel(),
             ["Dark"] = BuildDark(),
@@ -24,6 +25,8 @@ namespace OpenNest
             ["4th of July"] = BuildFourthOfJuly(),
         };
 
+        public const string DefaultSchemeName = "Blueprint";
+
         private static List<ColorScheme> diskCache;
 
         public static IEnumerable<ColorScheme> AllSchemes
@@ -40,12 +43,12 @@ namespace OpenNest
         public static ColorScheme Get(string name)
         {
             if (string.IsNullOrWhiteSpace(name))
-                return builtIns["Classic"];
+                return builtIns[DefaultSchemeName];
 
             var hit = AllSchemes.FirstOrDefault(s =>
                 string.Equals(s.Name, name, StringComparison.OrdinalIgnoreCase)
             );
-            return hit ?? builtIns["Classic"];
+            return hit ?? builtIns[DefaultSchemeName];
         }
 
         public static void ApplyActiveFromSettings()
@@ -227,6 +230,39 @@ namespace OpenNest
                 },
             };
 
+        // The default scheme. Its twelve fills were picked farthest-first in Lab (at least
+        // ~30 CIE76 apart), readable with black part IDs and clear of etch green, the sheet
+        // and the canvas.
+        private static ColorScheme BuildBlueprint() =>
+            new ColorScheme
+            {
+                Name = "Blueprint",
+                BackgroundColor = Color.FromArgb(24, 52, 92),
+                LayoutOutlineColor = Color.FromArgb(120, 150, 190),
+                LayoutFillColor = Color.FromArgb(226, 236, 246),
+                BoundingBoxColor = Color.FromArgb(140, 200, 255),
+                RapidColor = Color.FromArgb(230, 90, 40),
+                OriginColor = Color.FromArgb(150, 175, 205),
+                EdgeSpacingColor = Color.FromArgb(160, 185, 215),
+                PreviewPartColor = Color.FromArgb(255, 200, 40),
+                PartOutlineColor = Color.FromArgb(20, 40, 70),
+                PartColors = new[]
+                {
+                    Color.FromArgb(232, 136, 79),
+                    Color.FromArgb(32, 168, 253),
+                    Color.FromArgb(116, 242, 171),
+                    Color.FromArgb(252, 138, 213),
+                    Color.FromArgb(198, 198, 88),
+                    Color.FromArgb(28, 231, 250),
+                    Color.FromArgb(248, 186, 187),
+                    Color.FromArgb(137, 169, 132),
+                    Color.FromArgb(169, 152, 202),
+                    Color.FromArgb(253, 116, 137),
+                    Color.FromArgb(238, 216, 165),
+                    Color.FromArgb(104, 169, 195),
+                },
+            };
+
         private static ColorScheme BuildClassic() =>
             new ColorScheme
             {

OpenNest/Forms/OptionsForm.cs

@@ -99,7 +99,7 @@ namespace OpenNest.Forms
             Settings.Default.CreateNewNestOnOpen = checkBox1.Checked;
             Settings.Default.AutoSizePlateFactor = (double)numericUpDown1.Value;
             Settings.Default.ActiveColorScheme =
-                colorSchemeCombo.SelectedItem as string ?? "Classic";
+                colorSchemeCombo.SelectedItem as string ?? ColorSchemeRegistry.DefaultSchemeName;
 
             var disabledNames = new List<string>();
             foreach (DataGridViewRow row in strategyGrid.Rows)

OpenNest/Properties/Settings.Designer.cs

@@ -283,7 +283,7 @@ namespace OpenNest.Properties {
 
         [global::System.Configuration.UserScopedSettingAttribute()]
         [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
-        [global::System.Configuration.DefaultSettingValueAttribute("Classic")]
+        [global::System.Configuration.DefaultSettingValueAttribute("Blueprint")]
         public string ActiveColorScheme {
             get {
                 return ((string)(this["ActiveColorScheme"]));

OpenNest/Properties/Settings.settings

@@ -69,7 +69,7 @@
       <Value Profile="(Default)" />
     </Setting>
     <Setting Name="ActiveColorScheme" Type="System.String" Scope="User">
-      <Value Profile="(Default)">Classic</Value>
+      <Value Profile="(Default)">Blueprint</Value>
     </Setting>
     <Setting Name="UpdateFeedUrl" Type="System.String" Scope="User">
       <Value Profile="(Default)" />

docs/nesting-view-colors.md

@@ -1,5 +1,16 @@
 # Nesting-view colors
 
+## Default scheme
+
+**Blueprint** is the default for new installs and the fallback for missing or
+unknown scheme names: deep navy canvas, pale blue sheet, dark navy part
+outlines, orange-red rapids and twelve part fills at least ~30 CIE76 apart that
+stay readable with black part IDs and clear of the etch green, the sheet and the
+canvas. A scheme already saved in **Tools > Options** is kept; choose Blueprint
+there to switch an existing install. Classic remains available.
+
+## Workshop
+
 Choose **Tools > Options > Color scheme > Workshop**, then **Save** for a
 high-contrast per-drawing view: