diff --git a/HellionChat/Themes/Builtin/HellionArctic.cs b/HellionChat/Themes/Builtin/HellionArctic.cs
new file mode 100644
index 0000000..38ed5b6
--- /dev/null
+++ b/HellionChat/Themes/Builtin/HellionArctic.cs
@@ -0,0 +1,50 @@
+using HellionChat.Util;
+
+namespace HellionChat.Themes.Builtin;
+
+internal static class HellionArctic
+{
+    public const string Slug = "hellion-arctic";
+
+    public static Theme Build() => new(
+        Slug: Slug,
+        Name: "Hellion Arctic",
+        Author: "Hellion Online Media",
+        Description: "Arctic Cyan + Ember Glow on industrial slate. Plugin default.",
+        Colors: new ThemeColors(
+            PrimaryDark:    ColourUtil.HexToRgba("#0097A7"),
+            Primary:        ColourUtil.HexToRgba("#00BED2"),
+            PrimaryLight:   ColourUtil.HexToRgba("#4DD9E8"),
+            PrimaryGlow:    ColourUtil.HexToRgba("#00BED299"),
+
+            AccentDark:     ColourUtil.HexToRgba("#E85D04"),
+            Accent:         ColourUtil.HexToRgba("#F97316"),
+            AccentLight:    ColourUtil.HexToRgba("#FB923C"),
+
+            Identity:       ColourUtil.HexToRgba("#0097A7"),
+
+            WindowBg:       ColourUtil.HexToRgba("#070B12"),
+            ChildBg:        ColourUtil.HexToRgba("#0C1220"),
+            FrameBg:        ColourUtil.HexToRgba("#141E30"),
+            Surface:        ColourUtil.HexToRgba("#1A2538"),
+            SurfaceHover:   ColourUtil.HexToRgba("#22303F"),
+            Border:         ColourUtil.HexToRgba("#00BED266"),
+
+            TextPrimary:    ColourUtil.HexToRgba("#E6F4F1"),
+            TextMuted:      ColourUtil.HexToRgba("#8FA3B5"),
+            TextDim:        ColourUtil.HexToRgba("#566273"),
+
+            StatusSuccess:  ColourUtil.HexToRgba("#5CB85C"),
+            StatusDanger:   ColourUtil.HexToRgba("#D9534F"),
+            StatusWarning:  ColourUtil.HexToRgba("#F0AD4E"),
+            StatusInfo:     ColourUtil.HexToRgba("#00BED2")
+        ),
+        Layout: new ThemeLayout(
+            WindowRounding: 4f, ChildRounding: 3f, PopupRounding: 3f,
+            FrameRounding: 2f, GrabRounding: 2f, TabRounding: 2f,
+            ScrollbarRounding: 2f, WindowBorderSize: 1f, FrameBorderSize: 1f
+        ),
+        Typography: new ThemeTypography(),
+        IsBuiltIn: true
+    );
+}