Index: binaries/data/config/default.cfg
===================================================================
--- binaries/data/config/default.cfg
+++ binaries/data/config/default.cfg
@@ -381,6 +381,12 @@
 enable = true                     ; Enable/disable the splashscreen
 version = 0                       ; Splashscreen version (date of last modification). By default, 0 to force splashscreen to appear at first launch
 
+[diplomacycolors]
+self = "21 55 149"                ; Color of your units when diplomacy colors are enabled
+ally = "86 180 31"                ; Color of allies when diplomacy colors are enabled
+neutral = "231 200 5"             ; Color of neutral players when diplomacy colors are enabled
+enemy = "150 20 20"               ; Color of enemies when diplomacy colors are enabled
+
 [joystick]        ; EXPERIMENTAL: joystick/gamepad settings
 enable = false
 deadzone = 8192
Index: binaries/data/mods/public/gui/common/color.js
===================================================================
--- binaries/data/mods/public/gui/common/color.js
+++ binaries/data/mods/public/gui/common/color.js
@@ -24,6 +24,22 @@
 }
 
 /**
+ * Extract RGB colors from a string
+ *
+ * @param {string} color string
+ * @returns {Object}
+ */
+function guiToRgbColor(string)
+{
+	let color = string.split(" ");
+	return {
+		"r": Number(color[0] || 0),
+		"g": Number(color[1] || 0),
+		"b": Number(color[2] || 0)
+	};
+}
+
+/**
  * True if the colors are identical.
  *
  * @param {Object} color1
Index: binaries/data/mods/public/gui/options/options.json
===================================================================
--- binaries/data/mods/public/gui/options/options.json
+++ binaries/data/mods/public/gui/options/options.json
@@ -426,6 +426,30 @@
 					{ "value": "buddies", "label": "Buddies" },
 					{ "value": "disabled", "label": "Disabled" }
 				]
+			},
+			{
+				"type": "string",
+				"label": "Diplomacy Colors: Self",
+				"tooltip": "Color of your units when diplomacy colors are enabled. (Default RGB string = 21 55 149)",
+				"config": "diplomacycolors.self"
+			},
+			{
+				"type": "string",
+				"label": "Diplomacy Colors: Ally",
+				"tooltip": "Color of allies when diplomacy colors are enabled. (Default RGB string = 86 180 31)",
+				"config": "diplomacycolors.ally"
+			},
+			{
+				"type": "string",
+				"label": "Diplomacy Colors: Neutral",
+				"tooltip": "Color of neutral players when diplomacy colors are enabled. (Default RGB string = 231 200 5)",
+				"config": "diplomacycolors.neutral"
+			},
+			{
+				"type": "string",
+				"label": "Diplomacy Colors: Enemy",
+				"tooltip": "Color of enemies when diplomacy colors are enabled. (Default RGB string = 150 20 20)",
+				"config": "diplomacycolors.enemy"
 			}
 		]
 	},
Index: binaries/data/mods/public/gui/session/menu.js
===================================================================
--- binaries/data/mods/public/gui/session/menu.js
+++ binaries/data/mods/public/gui/session/menu.js
@@ -1143,6 +1143,9 @@
 
 function resumeGame(explicit = false)
 {
+	if (g_DiplomacyColorsToggle)
+		updateDisplayedPlayerColors();
+
 	pauseGame(false, explicit);
 }
 
Index: binaries/data/mods/public/gui/session/session.js
===================================================================
--- binaries/data/mods/public/gui/session/session.js
+++ binaries/data/mods/public/gui/session/session.js
@@ -23,7 +23,7 @@
 var g_DisplayedPlayerColors;
 
 /**
- * The self/ally/neutral/enemy color codes.
+ * The default self/ally/neutral/enemy color codes.
  */
 var g_DiplomacyColorPalette;
 
@@ -389,6 +389,14 @@
 	updateDisplayedPlayerColors();
 }
 
+function sanitizeDiplomacyColor(stance)
+{
+	let validColor = num => Number.isInteger(num) && num >= 0 && num <= 255;
+	let color = guiToRgbColor(Engine.ConfigDB_GetValue("user", "diplomacycolors." + stance));
+	return validColor(color.r) && validColor(color.g) && validColor(color.b) ?
+		color : g_DiplomacyColorPalette[stance];
+}
+
 /**
  * Updates the displayed colors of players in the simulation and GUI.
  */
@@ -409,10 +417,10 @@
 			else
 				// Players see colors depending on diplomacy
 				g_DisplayedPlayerColors[i] =
-					g_ViewedPlayer == i ? g_DiplomacyColorPalette.Self :
-					g_Players[g_ViewedPlayer].isAlly[i] ? g_DiplomacyColorPalette.Ally :
-					g_Players[g_ViewedPlayer].isNeutral[i] ? g_DiplomacyColorPalette.Neutral :
-					g_DiplomacyColorPalette.Enemy;
+					g_ViewedPlayer == i ? sanitizeDiplomacyColor("self") :
+					g_Players[g_ViewedPlayer].isAlly[i] ? sanitizeDiplomacyColor("ally") :
+					g_Players[g_ViewedPlayer].isNeutral[i] ? sanitizeDiplomacyColor("neutral") :
+					sanitizeDiplomacyColor("enemy");
 
 		g_DisplayedPlayerColors[0] = g_Players[0].color;
 	}
Index: binaries/data/mods/public/simulation/data/settings/diplomacy_colors.json
===================================================================
--- binaries/data/mods/public/simulation/data/settings/diplomacy_colors.json
+++ binaries/data/mods/public/simulation/data/settings/diplomacy_colors.json
@@ -1,6 +1,6 @@
 {
-	"Self": { "r": 0, "g": 68, "b": 255 },
-	"Ally": { "r": 94, "g": 255, "b": 0 },
-	"Neutral": { "r": 255, "g": 220, "b": 0 },
-	"Enemy": { "r": 255, "g": 0, "b": 0 }
+	"self": { "r": 21, "g": 55, "b": 149 },
+	"ally": { "r": 86, "g": 180, "b": 31 },
+	"neutral": { "r": 231, "g": 200, "b": 5 },
+	"enemy": { "r": 150, "g": 20, "b": 20 }
 }