add dark terrastruct flagship theme

ci/release/changelogs/next.md

@@ -2,6 +2,7 @@
 
 - Export diagrams to `.pptx` (PowerPoint)[#1139](https://github.com/terrastruct/d2/pull/1139)
 - Customize gap size in grid diagrams with `grid-gap`, `vertical-gap`, or `horizontal-gap` [#1178](https://github.com/terrastruct/d2/issues/1178)
+- New dark theme "Dark Terrastruct Flagship" with the theme ID of `2` [#1150](https://github.com/terrastruct/d2/issues/1150)
 
 #### Improvements 🧹
 

d2themes/d2themes.go

@@ -78,6 +78,16 @@ var WarmNeutral = Neutral{
 }
 
 var DarkNeutral = Neutral{
+	N1: "#F4F6FA",
+	N2: "#BBBEC9",
+	N3: "#868A96",
+	N4: "#3A3D49",
+	N5: "#676D7D",
+	N6: "#191C28",
+	N7: "#000410",
+}
+
+var DarkMauveNeutral = Neutral{
 	N1: "#CDD6F4",
 	N2: "#BAC2DE",
 	N3: "#A6ADC8",

d2themes/d2themescatalog/catalog.go

@@ -11,8 +11,8 @@ var LightCatalog = []d2themes.Theme{
 	NeutralDefault,
 	NeutralGrey,
 	FlagshipTerrastruct,
-	MixedBerryBlue,
 	CoolClassics,
+	MixedBerryBlue,
 	GrapeSoda,
 	Aubergine,
 	ColorblindClear,
@@ -28,6 +28,7 @@ var LightCatalog = []d2themes.Theme{
 }
 
 var DarkCatalog = []d2themes.Theme{
+	DarkFlagshipTerrastruct,
 	DarkMauve,
 }
 

d2themes/d2themescatalog/dark_flagship_terrastruct.go

@@ -0,0 +1,25 @@
+package d2themescatalog
+
+import "oss.terrastruct.com/d2/d2themes"
+
+var DarkFlagshipTerrastruct = d2themes.Theme{
+	ID:   2,
+	Name: "Dark Flagship Terrastruct",
+	Colors: d2themes.ColorPalette{
+		Neutrals: d2themes.DarkNeutral,
+
+		B1: "#F4F6FA",
+		B2: "#6B8AFB",
+		B3: "#3733E9",
+		B4: "#070B67",
+		B5: "#0B1197",
+		B6: "#3733E9",
+
+		AA2: "#8B5DEE",
+		AA4: "#4918B1",
+		AA5: "#7240DD",
+
+		AB4: "#00607C",
+		AB5: "#01799D",
+	},
+}

d2themes/d2themescatalog/dark_mauve.go

@@ -6,7 +6,7 @@ var DarkMauve = d2themes.Theme{
 	ID:   200,
 	Name: "Dark Mauve",
 	Colors: d2themes.ColorPalette{
-		Neutrals: d2themes.DarkNeutral,
+		Neutrals: d2themes.DarkMauveNeutral,
 
 		B1: "#CBA6f7",
 		B2: "#CBA6f7",