diff --git a/README.md b/README.md
index f26364a..b064677 100644
--- a/README.md
+++ b/README.md
@@ -160,7 +160,7 @@ Markdown responses render with per-language syntax highlighting directly in the
 - Slash-command autocomplete — type `/` for a fuzzy-filtered live suggestion strip
 - Collapsible tool output and thinking blocks — click to expand
 - Full mouse support: click, scroll, drag-select
-- 13 themes: `dark`, `light`, `dracula`, `nord`, `ayu`, `catppuccin`, `gruvbox`, `neon`, `synthwave`, `ember`, `matrix`, `cobalt`, `midnight` (`/theme`)
+- 14 themes: `dark`, `light`, `dracula`, `nord`, `ayu`, `catppuccin`, `gruvbox`, `neon`, `synthwave`, `ember`, `matrix`, `cobalt`, `midnight`, `tokyo-night` (`/theme`)
 - Vim keybindings (`/vimmode on`)
 - Sidebar: usage, context window fill, MCP servers, routing analytics
 - Diffs render as colored, syntax-highlighted unified-diff blocks — including multi-file patches
diff --git a/assets/tokyo-night-theme.png b/assets/tokyo-night-theme.png
new file mode 100644
index 0000000..b32cd56
Binary files /dev/null and b/assets/tokyo-night-theme.png differ
diff --git a/src/auth/credentials.ts b/src/auth/credentials.ts
index d7fa73c..afe0141 100644
--- a/src/auth/credentials.ts
+++ b/src/auth/credentials.ts
@@ -28,7 +28,7 @@ export interface Credentials {
 export interface Config {
   baseUrl: string;             // KlaatAI API base URL
   routingDisplay: "minimal" | "full" | "off";
-  theme: string;               // Theme name: dark | light | dracula | nord | ayu | catppuccin | gruvbox
+  theme: string;               // Theme name from THEME_NAMES (for example dark, light, tokyo-night)
   vimMode: boolean;            // Vim-style key bindings in the input field
   /**
    * Disable TLS certificate verification (corporate MITM proxies whose root
diff --git a/src/engine/theme.test.ts b/src/engine/theme.test.ts
new file mode 100644
index 0000000..5a67ea2
--- /dev/null
+++ b/src/engine/theme.test.ts
@@ -0,0 +1,42 @@
+import { describe, expect, test } from "bun:test";
+import {
+  THEME_DESCRIPTIONS,
+  THEME_NAMES,
+  TOKYO_NIGHT_PALETTE,
+  getPalette,
+} from "./theme.js";
+
+describe("Tokyo Night theme", () => {
+  test("is registered with its description and palette", () => {
+    expect(THEME_NAMES).toContain("tokyo-night");
+    expect(THEME_DESCRIPTIONS["tokyo-night"]).toContain("Tokyo Night");
+    expect(getPalette("tokyo-night")).toBe(TOKYO_NIGHT_PALETTE);
+  });
+
+  test("uses valid 256-color slots", () => {
+    const numericSlots = Object.values(TOKYO_NIGHT_PALETTE)
+      .filter((value): value is number => typeof value === "number");
+
+    expect(numericSlots.length).toBeGreaterThan(0);
+    for (const color of numericSlots) {
+      expect(Number.isInteger(color)).toBe(true);
+      expect(color).toBeGreaterThanOrEqual(0);
+      expect(color).toBeLessThanOrEqual(255);
+    }
+  });
+
+  test("uses supported hex colors and the terminal background", () => {
+    const hexSlots = [
+      TOKYO_NIGHT_PALETTE.accent,
+      TOKYO_NIGHT_PALETTE.dimText,
+      TOKYO_NIGHT_PALETTE.userColor,
+      TOKYO_NIGHT_PALETTE.border,
+      TOKYO_NIGHT_PALETTE.thumb,
+    ];
+
+    for (const color of hexSlots) {
+      expect(color).toMatch(/^#[0-9a-f]{6}$/i);
+    }
+    expect(TOKYO_NIGHT_PALETTE.bg).toBeNull();
+  });
+});
diff --git a/src/engine/theme.ts b/src/engine/theme.ts
index 384c29a..98ec12b 100644
--- a/src/engine/theme.ts
+++ b/src/engine/theme.ts
@@ -328,6 +328,27 @@ export const MIDNIGHT_PALETTE: ThemePalette = {
   assistantFg:  117,  // sky blue
 };
 
+/** Tokyo Night — deep navy with cool blue and green accents */
+export const TOKYO_NIGHT_PALETTE: ThemePalette = {
+  accent:       "#7aa2f7",  // blue
+  dimText:      "#7f87b2",  // dark foreground
+  userColor:    "#9ece6a",  // green
+  border:       "#3b4261",  // terminal black
+  thumb:        "#545c7e",
+  bg:           null,
+  inputBg:      234,
+  chatFg:       189,  // pale blue-white
+  mutedFg:      103,  // muted lavender-blue
+  toolFg:       110,  // cyan-blue
+  codeFg:       111,  // bright blue
+  codeBg:       235,
+  headingFg:    "white",
+  sidebarLabel: 103,
+  sidebarValue: 189,
+  userFg:       149,  // green
+  assistantFg:  111,  // blue
+};
+
 export type Theme =
   | "dark"
   | "light"
@@ -341,11 +362,12 @@ export type Theme =
   | "ember"
   | "matrix"
   | "cobalt"
-  | "midnight";
+  | "midnight"
+  | "tokyo-night";
 
 export const THEME_NAMES: Theme[] = [
   "dark", "light", "dracula", "nord", "ayu", "catppuccin", "gruvbox",
-  "neon", "synthwave", "ember", "matrix", "cobalt", "midnight",
+  "neon", "synthwave", "ember", "matrix", "cobalt", "midnight", "tokyo-night",
 ];
 
 export const THEME_DESCRIPTIONS: Record<Theme, string> = {
@@ -362,6 +384,7 @@ export const THEME_DESCRIPTIONS: Record<Theme, string> = {
   matrix:     "Matrix — green phosphor terminal aesthetic",
   cobalt:     "Cobalt — deep blue with golden highlights",
   midnight:   "Midnight — indigo depths with sky blue & lavender",
+  "tokyo-night": "Tokyo Night — deep navy with cool blue & green",
 };
 
 export function getPalette(theme: Theme): ThemePalette {
@@ -378,6 +401,7 @@ export function getPalette(theme: Theme): ThemePalette {
     case "matrix":     return MATRIX_PALETTE;
     case "cobalt":     return COBALT_PALETTE;
     case "midnight":   return MIDNIGHT_PALETTE;
+    case "tokyo-night": return TOKYO_NIGHT_PALETTE;
     default:           return DARK_PALETTE;
   }
 }
@@ -446,4 +470,3 @@ export async function detectTheme(): Promise<Theme> {
     timer = setTimeout(() => finish("dark"), 200);
   });
 }
-