diff --git a/HellionChat/Themes/Builtin/HellionSpectrum.cs b/HellionChat/Themes/Builtin/HellionSpectrum.cs
new file mode 100644
index 0000000..5175bcd
--- /dev/null
+++ b/HellionChat/Themes/Builtin/HellionSpectrum.cs
@@ -0,0 +1,83 @@
+using HellionChat.Util;
+
+namespace HellionChat.Themes.Builtin;
+
+// Hellion Spectrum: Deuteran/Protan-safe channel colours.
+// Palette derived from Bang Wong, "Points of view: Color blindness",
+// Nature Methods 8, 441 (2011). Channel identity (Tell pink, Yell yellow,
+// Shout orange, Party blue, FC green) is preserved per Channel-Identity-
+// Rule in docs/THEME-AUTHORING.md; tones are chosen so every channel
+// stays distinguishable under red-green colour-vision deficiency.
+internal static class HellionSpectrum
+{
+    public const string Slug = "hellion-spectrum";
+
+    public static Theme Build() => new(
+        Slug: Slug,
+        Name: "Hellion Spectrum",
+        Author: "Hellion Online Media",
+        Description: "Deuteran/Protan-safe channels — Wong palette tones, channel identity preserved.",
+        Colors: new ThemeColors(
+            PrimaryDark:    ColourUtil.HexToRgba("#005983"),
+            Primary:        ColourUtil.HexToRgba("#0072B2"),
+            PrimaryLight:   ColourUtil.HexToRgba("#3E9BD0"),
+            PrimaryGlow:    ColourUtil.HexToRgba("#0072B299"),
+
+            AccentDark:     ColourUtil.HexToRgba("#B07F00"),
+            Accent:         ColourUtil.HexToRgba("#E69F00"),
+            AccentLight:    ColourUtil.HexToRgba("#F0B73A"),
+
+            Identity:       ColourUtil.HexToRgba("#005983"),
+
+            WindowBg:       ColourUtil.HexToRgba("#0A0F14"),
+            ChildBg:        ColourUtil.HexToRgba("#101620"),
+            FrameBg:        ColourUtil.HexToRgba("#1A222E"),
+            Surface:        ColourUtil.HexToRgba("#22303F"),
+            SurfaceHover:   ColourUtil.HexToRgba("#2D3E51"),
+            Border:         ColourUtil.HexToRgba("#0072B266"),
+
+            TextPrimary:    ColourUtil.HexToRgba("#F0F4F8"),
+            TextMuted:      ColourUtil.HexToRgba("#9AA8B5"),
+            TextDim:        ColourUtil.HexToRgba("#5E6B78"),
+
+            StatusSuccess:  ColourUtil.HexToRgba("#009E73"),
+            StatusDanger:   ColourUtil.HexToRgba("#D55E00"),
+            StatusWarning:  ColourUtil.HexToRgba("#F0E442"),
+            StatusInfo:     ColourUtil.HexToRgba("#56B4E9")
+        ),
+        Layout: new ThemeLayout(
+            WindowRounding: 6f, ChildRounding: 5f, PopupRounding: 5f,
+            FrameRounding: 4f, GrabRounding: 4f, TabRounding: 4f,
+            ScrollbarRounding: 4f, WindowBorderSize: 1f, FrameBorderSize: 1f
+        ),
+        Typography: new ThemeTypography(),
+        IsBuiltIn: true,
+        ChatColors: new ThemeChatColors(new Dictionary<HellionChat.Code.ChatType, uint>
+        {
+            // Hellion Spectrum — Wong/Okabe-Ito tones within FFXIV channel
+            // identity. FC pulled slightly greener than vanilla cyan-teal so
+            // Party-blue and FC-green stay separable under deuteran sim.
+            [HellionChat.Code.ChatType.Say]              = ColourUtil.HexToRgba("#FFFFFF"),
+            [HellionChat.Code.ChatType.Yell]             = ColourUtil.HexToRgba("#F0E442"),
+            [HellionChat.Code.ChatType.Shout]            = ColourUtil.HexToRgba("#D55E00"),
+            [HellionChat.Code.ChatType.TellIncoming]     = ColourUtil.HexToRgba("#CC79A7"),
+            [HellionChat.Code.ChatType.TellOutgoing]     = ColourUtil.HexToRgba("#CC79A7"),
+            [HellionChat.Code.ChatType.Party]            = ColourUtil.HexToRgba("#56B4E9"),
+            [HellionChat.Code.ChatType.Alliance]         = ColourUtil.HexToRgba("#E69F00"),
+            [HellionChat.Code.ChatType.FreeCompany]      = ColourUtil.HexToRgba("#009E73"),
+            [HellionChat.Code.ChatType.NoviceNetwork]    = ColourUtil.HexToRgba("#94CC4A"),
+            [HellionChat.Code.ChatType.CrossParty]       = ColourUtil.HexToRgba("#56B4E9"),
+            [HellionChat.Code.ChatType.Linkshell1]       = ColourUtil.HexToRgba("#94CC4A"),
+            [HellionChat.Code.ChatType.Linkshell2]       = ColourUtil.HexToRgba("#E69F00"),
+            [HellionChat.Code.ChatType.Linkshell3]       = ColourUtil.HexToRgba("#F0E442"),
+            [HellionChat.Code.ChatType.Linkshell4]       = ColourUtil.HexToRgba("#66D9A8"),
+            [HellionChat.Code.ChatType.Linkshell5]       = ColourUtil.HexToRgba("#56B4E9"),
+            [HellionChat.Code.ChatType.Linkshell6]       = ColourUtil.HexToRgba("#8B7DD0"),
+            [HellionChat.Code.ChatType.Linkshell7]       = ColourUtil.HexToRgba("#E0A0C0"),
+            [HellionChat.Code.ChatType.Linkshell8]       = ColourUtil.HexToRgba("#DAA0DA"),
+            [HellionChat.Code.ChatType.CustomEmote]      = ColourUtil.HexToRgba("#C9A56F"),
+            [HellionChat.Code.ChatType.StandardEmote]    = ColourUtil.HexToRgba("#C9A56F"),
+            [HellionChat.Code.ChatType.Echo]             = ColourUtil.HexToRgba("#C0C0C0"),
+        })
+    );
+}
diff --git a/HellionChat/Themes/ThemeRegistry.cs b/HellionChat/Themes/ThemeRegistry.cs
index 1bda072..62c0f8a 100644
--- a/HellionChat/Themes/ThemeRegistry.cs
+++ b/HellionChat/Themes/ThemeRegistry.cs
@@ -16,6 +16,7 @@ public sealed class ThemeRegistry
         _builtIns = new Dictionary<string, Theme>(StringComparer.OrdinalIgnoreCase)
         {
             { HellionArctic.Slug,     HellionArctic.Build() },
+            { HellionSpectrum.Slug,   HellionSpectrum.Build() },
             { Chat2Classic.Slug,      Chat2Classic.Build() },
             { EventHorizon.Slug,      EventHorizon.Build() },
             { MoonlitBloom.Slug,      MoonlitBloom.Build() },