diff --git a/locale/fr.json b/locale/fr.json
index e42bcda..f1352ec 100755
--- a/locale/fr.json
+++ b/locale/fr.json
@@ -69,9 +69,9 @@
 	"Hide other Commands": "Masquer les autres commandes",
 	"Double click to enter custom value": "Double-cliquez pour entrer une valeur personnalisée",
 	"Choose custom spacing for Command Buttons": "Choisissez un espacement personnalisé pour les boutons de commande",
-	"Change the spacing between commands.": "Modifier l'espacement entre les commandes.",
+	"Change the spacing between commands. You can set different values on mobile and desktop.": "Modifier l'espacement entre les commandes.",
 	"Warning": "Avertissement",
-	"As of Obsidian 0.16.0 you need to explicitly enable the Tab Title Bar. Once enabled, you might need to restart Obsidian.": "À partir d'Obsidian 0.16.0, vous devez activer explicitement la barre de titre des onglets. Une fois activée, il se peut que vous deviez redémarrer Obsidian.",
+	"As of Obsidian 0.16.0 you need to explicitly enable the View Header.": "À partir d'Obsidian 0.16.0, vous devez activer explicitement la barre de titre des onglets. Une fois activée, il se peut que vous deviez redémarrer Obsidian.",
 	"Open Appearance Settings": "Ouvrir les paramètres d'apparence",
 	"Explorer": "Explorateur"
 }
diff --git a/src/__tests__/__mocks__/l10n.ts b/src/__tests__/__mocks__/l10n.ts
new file mode 100644
index 0000000..9ce37b4
--- /dev/null
+++ b/src/__tests__/__mocks__/l10n.ts
@@ -0,0 +1,3 @@
+export default function t(str: string): string {
+	return str;
+}
diff --git a/src/__tests__/__mocks__/obsidian.ts b/src/__tests__/__mocks__/obsidian.ts
new file mode 100644
index 0000000..ff738d3
--- /dev/null
+++ b/src/__tests__/__mocks__/obsidian.ts
@@ -0,0 +1,43 @@
+// Minimal Obsidian API mock for unit tests
+
+// moment is a global in Obsidian; provide a minimal stub
+(globalThis as Record<string, unknown>).moment = { locale: () => "en" };
+
+export const Platform = {
+	isDesktop: true,
+	isMobile: false,
+};
+
+export function setIcon(el: HTMLElement, icon: string): void {
+	el.setAttribute("data-icon", icon);
+}
+
+export function requireApiVersion(_version: string): boolean {
+	return true;
+}
+
+export function getIconIds(): string[] {
+	return ["check", "x", "star", "home"];
+}
+
+export class Plugin {}
+export class Modal {}
+export class Setting {}
+export class FuzzySuggestModal<T> {
+	app: unknown;
+	constructor(app: unknown) { this.app = app; }
+	open() {}
+	close() {}
+}
+export class SuggestModal<T> {
+	app: unknown;
+	constructor(app: unknown) { this.app = app; }
+	open() {}
+	close() {}
+}
+export class PluginSettingTab {
+	app: unknown;
+	plugin: unknown;
+	containerEl: HTMLElement = document.createElement("div");
+	constructor(app: unknown, plugin: unknown) { this.app = app; this.plugin = plugin; }
+}
diff --git a/src/__tests__/executeMacro.test.ts b/src/__tests__/executeMacro.test.ts
new file mode 100644
index 0000000..07d39ef
--- /dev/null
+++ b/src/__tests__/executeMacro.test.ts
@@ -0,0 +1,89 @@
+import { describe, it, expect, vi } from "vitest";
+import { Action } from "../types";
+import type { Macro } from "../types";
+import type CommanderPlugin from "../main";
+import CommanderPluginClass from "../main";
+
+function buildPlugin(macros: Macro[]): CommanderPlugin {
+	const executeCommandById = vi.fn();
+	const plugin = {
+		settings: { macros },
+		app: {
+			commands: { executeCommandById },
+		},
+	} as unknown as CommanderPlugin;
+	plugin.executeMacro = CommanderPluginClass.prototype.executeMacro.bind(plugin);
+	return plugin;
+}
+
+describe("executeMacro", () => {
+	it("throws when macro id does not exist", async () => {
+		const plugin = buildPlugin([]);
+		await expect(plugin.executeMacro(99)).rejects.toThrow("Macro not found");
+	});
+
+	it("executes COMMAND actions by calling executeCommandById", async () => {
+		const macro: Macro = {
+			name: "test",
+			icon: "check",
+			macro: [
+				{ action: Action.COMMAND, commandId: "editor:undo" },
+				{ action: Action.COMMAND, commandId: "editor:redo" },
+			],
+		};
+		const plugin = buildPlugin([macro]);
+		await plugin.executeMacro(0);
+		const spy = plugin.app.commands.executeCommandById as ReturnType<typeof vi.fn>;
+		expect(spy).toHaveBeenCalledTimes(2);
+		expect(spy).toHaveBeenNthCalledWith(1, "editor:undo");
+		expect(spy).toHaveBeenNthCalledWith(2, "editor:redo");
+	});
+
+	it("executes LOOP action the correct number of times", async () => {
+		const macro: Macro = {
+			name: "loop-test",
+			icon: "star",
+			macro: [{ action: Action.LOOP, times: 3, commandId: "some:command" }],
+		};
+		const plugin = buildPlugin([macro]);
+		await plugin.executeMacro(0);
+		const spy = plugin.app.commands.executeCommandById as ReturnType<typeof vi.fn>;
+		expect(spy).toHaveBeenCalledTimes(3);
+	});
+
+	it("handles DELAY action without throwing", async () => {
+		const macro: Macro = {
+			name: "delay-test",
+			icon: "home",
+			macro: [{ action: Action.DELAY, delay: 0 }],
+		};
+		const plugin = buildPlugin([macro]);
+		await expect(plugin.executeMacro(0)).resolves.toBeUndefined();
+	});
+
+	it("handles EDITOR action without throwing", async () => {
+		const macro: Macro = {
+			name: "editor-test",
+			icon: "home",
+			macro: [{ action: Action.EDITOR }],
+		};
+		const plugin = buildPlugin([macro]);
+		await expect(plugin.executeMacro(0)).resolves.toBeUndefined();
+	});
+
+	it("executes mixed action sequence in correct order", async () => {
+		const macro: Macro = {
+			name: "mixed",
+			icon: "check",
+			macro: [
+				{ action: Action.COMMAND, commandId: "cmd-1" },
+				{ action: Action.DELAY, delay: 0 },
+				{ action: Action.COMMAND, commandId: "cmd-2" },
+			],
+		};
+		const plugin = buildPlugin([macro]);
+		await plugin.executeMacro(0);
+		const spy = plugin.app.commands.executeCommandById as ReturnType<typeof vi.fn>;
+		expect(spy.mock.calls.map((c: string[]) => c[0])).toEqual(["cmd-1", "cmd-2"]);
+	});
+});
diff --git a/src/__tests__/injectIcons.test.ts b/src/__tests__/injectIcons.test.ts
new file mode 100644
index 0000000..308b957
--- /dev/null
+++ b/src/__tests__/injectIcons.test.ts
@@ -0,0 +1,68 @@
+import { describe, it, expect } from "vitest";
+import { injectIcons } from "../util";
+import type CommanderPlugin from "../main";
+import type { AdvancedToolbarSettings } from "../types";
+
+function makePlugin(commands: Record<string, { icon?: string }>): CommanderPlugin {
+	return {
+		app: { commands: { commands } },
+	} as unknown as CommanderPlugin;
+}
+
+function makeSettings(
+	mappedIcons: AdvancedToolbarSettings["mappedIcons"]
+): AdvancedToolbarSettings {
+	return {
+		rowHeight: 48,
+		rowCount: 1,
+		spacing: 0,
+		buttonWidth: 48,
+		columnLayout: false,
+		mappedIcons,
+		tooltips: false,
+		heightOffset: 0,
+	};
+}
+
+describe("injectIcons", () => {
+	it("sets the icon on a matching command", () => {
+		const commands = { "my:command": { icon: "old-icon" } };
+		const settings = makeSettings([{ iconID: "star", commandID: "my:command" }]);
+		injectIcons(settings, makePlugin(commands));
+		expect(commands["my:command"].icon).toBe("star");
+	});
+
+	it("removes mappedIcon entry when command does not exist", () => {
+		const commands = {};
+		const settings = makeSettings([{ iconID: "star", commandID: "missing:command" }]);
+		injectIcons(settings, makePlugin(commands));
+		expect(settings.mappedIcons).toHaveLength(0);
+	});
+
+	it("leaves unrelated mapped icons intact", () => {
+		const commands = {
+			"cmd-a": { icon: "" },
+			"cmd-b": { icon: "" },
+		};
+		const settings = makeSettings([
+			{ iconID: "check", commandID: "cmd-a" },
+			{ iconID: "x", commandID: "cmd-b" },
+		]);
+		injectIcons(settings, makePlugin(commands));
+		expect(commands["cmd-a"].icon).toBe("check");
+		expect(commands["cmd-b"].icon).toBe("x");
+		expect(settings.mappedIcons).toHaveLength(2);
+	});
+
+	it("only prunes the missing command and keeps valid ones", () => {
+		const commands = { "exists:cmd": { icon: "" } };
+		const settings = makeSettings([
+			{ iconID: "star", commandID: "missing:cmd" },
+			{ iconID: "home", commandID: "exists:cmd" },
+		]);
+		injectIcons(settings, makePlugin(commands));
+		expect(settings.mappedIcons).toHaveLength(1);
+		expect(settings.mappedIcons[0].commandID).toBe("exists:cmd");
+		expect(commands["exists:cmd"].icon).toBe("home");
+	});
+});
diff --git a/src/__tests__/isModeActive.test.ts b/src/__tests__/isModeActive.test.ts
new file mode 100644
index 0000000..c726840
--- /dev/null
+++ b/src/__tests__/isModeActive.test.ts
@@ -0,0 +1,43 @@
+import { describe, it, expect } from "vitest";
+import { isModeActive } from "../util";
+import type CommanderPlugin from "../main";
+
+function makePlugin(isMobile: boolean, appId = "desktop-app"): CommanderPlugin {
+	return {
+		app: { isMobile, appId },
+	} as unknown as CommanderPlugin;
+}
+
+describe("isModeActive", () => {
+	it('returns true for mode "any" on desktop', () => {
+		expect(isModeActive("any", makePlugin(false))).toBe(true);
+	});
+
+	it('returns true for mode "any" on mobile', () => {
+		expect(isModeActive("any", makePlugin(true))).toBe(true);
+	});
+
+	it('returns true for mode "desktop" when not mobile', () => {
+		expect(isModeActive("desktop", makePlugin(false))).toBe(true);
+	});
+
+	it('returns false for mode "desktop" when on mobile', () => {
+		expect(isModeActive("desktop", makePlugin(true))).toBe(false);
+	});
+
+	it('returns true for mode "mobile" when on mobile', () => {
+		expect(isModeActive("mobile", makePlugin(true))).toBe(true);
+	});
+
+	it('returns false for mode "mobile" when on desktop', () => {
+		expect(isModeActive("mobile", makePlugin(false))).toBe(false);
+	});
+
+	it("returns true when mode matches the appId", () => {
+		expect(isModeActive("my-vault", makePlugin(false, "my-vault"))).toBe(true);
+	});
+
+	it("returns false when mode does not match appId and is not any/mobile/desktop", () => {
+		expect(isModeActive("other-vault", makePlugin(false, "my-vault"))).toBe(false);
+	});
+});
diff --git a/src/__tests__/locales.test.ts b/src/__tests__/locales.test.ts
new file mode 100644
index 0000000..683ae6a
--- /dev/null
+++ b/src/__tests__/locales.test.ts
@@ -0,0 +1,60 @@
+import { describe, it, expect } from "vitest";
+import { readdirSync, readFileSync } from "fs";
+import path from "path";
+import { fileURLToPath } from "url";
+
+const __filename = fileURLToPath(import.meta.url);
+const __dirname = path.dirname(__filename);
+const LOCALE_DIR = path.resolve(__dirname, "../../locale");
+
+function loadJson(file: string): Record<string, string> {
+	return JSON.parse(readFileSync(path.join(LOCALE_DIR, file), "utf-8"));
+}
+
+// Extract all {{placeholder}} tokens from a string
+function placeholders(str: string): string[] {
+	return [...str.matchAll(/\{\{[^}]+\}\}/g)].map((m) => m[0]).sort();
+}
+
+const en = loadJson("en.json");
+const enKeys = Object.keys(en);
+
+const localeFiles = readdirSync(LOCALE_DIR).filter(
+	(f) => f.endsWith(".json") && f !== "en.json"
+);
+
+// Only validate locales that have been filled in (not empty stubs)
+const filledLocales = localeFiles.filter((f) => {
+	const data = loadJson(f);
+	return Object.keys(data).length > 0;
+});
+
+describe("locale completeness (non-empty locales only)", () => {
+	it.each(filledLocales)("%s has no missing keys", (file) => {
+		const data = loadJson(file);
+		const missing = enKeys.filter((k) => !(k in data));
+		expect(missing, `Missing keys in ${file}`).toEqual([]);
+	});
+
+	it.each(filledLocales)("%s has no extra keys not in en.json", (file) => {
+		const data = loadJson(file);
+		const extra = Object.keys(data).filter((k) => !(k in en));
+		expect(extra, `Extra keys in ${file}`).toEqual([]);
+	});
+
+	it.each(filledLocales)("%s preserves all {{placeholders}}", (file) => {
+		const data = loadJson(file);
+		const mismatches: string[] = [];
+		for (const key of enKeys) {
+			if (!(key in data)) continue;
+			const expected = placeholders(en[key]);
+			const actual = placeholders(data[key]);
+			if (JSON.stringify(expected) !== JSON.stringify(actual)) {
+				mismatches.push(
+					`"${key}": expected ${JSON.stringify(expected)}, got ${JSON.stringify(actual)}`
+				);
+			}
+		}
+		expect(mismatches, `Placeholder mismatches in ${file}`).toEqual([]);
+	});
+});
diff --git a/src/__tests__/setup.ts b/src/__tests__/setup.ts
new file mode 100644
index 0000000..e4a67c1
--- /dev/null
+++ b/src/__tests__/setup.ts
@@ -0,0 +1,2 @@
+(globalThis as Record<string, unknown>).moment = { locale: () => "en" };
+export {};
diff --git a/src/__tests__/styles.test.ts b/src/__tests__/styles.test.ts
new file mode 100644
index 0000000..c1006f9
--- /dev/null
+++ b/src/__tests__/styles.test.ts
@@ -0,0 +1,79 @@
+import { describe, it, expect, beforeEach } from "vitest";
+import { updateStyles, removeStyles } from "../util";
+import type { AdvancedToolbarSettings } from "../types";
+
+const defaultSettings: AdvancedToolbarSettings = {
+	rowHeight: 48,
+	rowCount: 1,
+	spacing: 4,
+	buttonWidth: 48,
+	columnLayout: false,
+	mappedIcons: [],
+	tooltips: false,
+	heightOffset: 0,
+};
+
+beforeEach(() => {
+	document.body.className = "";
+	document.body.removeAttribute("style");
+});
+
+describe("updateStyles", () => {
+	it("sets CSS custom properties on document.body", () => {
+		updateStyles(defaultSettings);
+		const s = document.body.style;
+		expect(s.getPropertyValue("--at-button-height")).toBe("48px");
+		expect(s.getPropertyValue("--at-button-width")).toBe("48px");
+		expect(s.getPropertyValue("--at-row-count")).toBe("1");
+		expect(s.getPropertyValue("--at-spacing")).toBe("4px");
+		expect(s.getPropertyValue("--at-offset")).toBe("0px");
+	});
+
+	it("adds AT-row class when columnLayout is false", () => {
+		updateStyles({ ...defaultSettings, columnLayout: false });
+		expect(document.body.classList.contains("AT-row")).toBe(true);
+		expect(document.body.classList.contains("AT-column")).toBe(false);
+	});
+
+	it("adds AT-column class when columnLayout is true", () => {
+		updateStyles({ ...defaultSettings, columnLayout: true });
+		expect(document.body.classList.contains("AT-column")).toBe(true);
+		expect(document.body.classList.contains("AT-row")).toBe(false);
+	});
+
+	it("adds AT-multirow when rowCount > 1", () => {
+		updateStyles({ ...defaultSettings, rowCount: 3 });
+		expect(document.body.classList.contains("AT-multirow")).toBe(true);
+	});
+
+	it("does not add AT-multirow when rowCount === 1", () => {
+		updateStyles(defaultSettings);
+		expect(document.body.classList.contains("AT-multirow")).toBe(false);
+	});
+
+	it("adds AT-no-toolbar when rowCount === 0", () => {
+		updateStyles({ ...defaultSettings, rowCount: 0 });
+		expect(document.body.classList.contains("AT-no-toolbar")).toBe(true);
+	});
+});
+
+describe("removeStyles", () => {
+	it("removes CSS custom properties set by updateStyles", () => {
+		updateStyles(defaultSettings);
+		removeStyles();
+		const s = document.body.style;
+		expect(s.getPropertyValue("--at-button-height")).toBe("");
+		expect(s.getPropertyValue("--at-button-width")).toBe("");
+		expect(s.getPropertyValue("--at-row-count")).toBe("");
+		expect(s.getPropertyValue("--at-spacing")).toBe("");
+		expect(s.getPropertyValue("--at-offset")).toBe("");
+	});
+
+	it("removes layout classes set by updateStyles", () => {
+		updateStyles({ ...defaultSettings, rowCount: 2, columnLayout: true });
+		removeStyles();
+		expect(document.body.classList.contains("AT-multirow")).toBe(false);
+		expect(document.body.classList.contains("AT-row")).toBe(false);
+		expect(document.body.classList.contains("AT-column")).toBe(false);
+	});
+});
diff --git a/vitest.config.ts b/vitest.config.ts
new file mode 100644
index 0000000..7f17458
--- /dev/null
+++ b/vitest.config.ts
@@ -0,0 +1,26 @@
+import { defineConfig } from "vitest/config";
+import path from "path";
+
+export default defineConfig({
+	test: {
+		environment: "jsdom",
+		globals: false,
+		setupFiles: ["src/__tests__/setup.ts"],
+	},
+	resolve: {
+		alias: [
+			{
+				find: "obsidian",
+				replacement: path.resolve(__dirname, "src/__tests__/__mocks__/obsidian.ts"),
+			},
+			{
+				find: /.*\/l10n$/,
+				replacement: path.resolve(__dirname, "src/__tests__/__mocks__/l10n.ts"),
+			},
+			{
+				find: "src",
+				replacement: path.resolve(__dirname, "src"),
+			},
+		],
+	},
+});