diff --git a/apps/web/src/hooks/__tests__/use-encounter.test.ts b/apps/web/src/hooks/__tests__/use-encounter.test.ts
new file mode 100644
index 0000000..1181de0
--- /dev/null
+++ b/apps/web/src/hooks/__tests__/use-encounter.test.ts
@@ -0,0 +1,217 @@
+// @vitest-environment jsdom
+import type { BestiaryIndexEntry, PlayerCharacter } from "@initiative/domain";
+import { combatantId, creatureId, playerCharacterId } from "@initiative/domain";
+import { act, renderHook } from "@testing-library/react";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { useEncounter } from "../use-encounter.js";
+
+vi.mock("../../persistence/encounter-storage.js", () => ({
+	loadEncounter: vi.fn().mockReturnValue(null),
+	saveEncounter: vi.fn(),
+}));
+
+const { loadEncounter: mockLoad, saveEncounter: mockSave } =
+	await vi.importMock<typeof import("../../persistence/encounter-storage.js")>(
+		"../../persistence/encounter-storage.js",
+	);
+
+describe("useEncounter", () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+		mockLoad.mockReturnValue(null);
+	});
+
+	it("initializes with empty encounter when persistence returns null", () => {
+		const { result } = renderHook(() => useEncounter());
+
+		expect(result.current.encounter.combatants).toEqual([]);
+		expect(result.current.encounter.activeIndex).toBe(0);
+		expect(result.current.encounter.roundNumber).toBe(1);
+		expect(result.current.isEmpty).toBe(true);
+	});
+
+	it("initializes from stored encounter", () => {
+		const stored = {
+			combatants: [{ id: combatantId("c-1"), name: "Goblin" }],
+			activeIndex: 0,
+			roundNumber: 2,
+		};
+		mockLoad.mockReturnValue(stored);
+
+		const { result } = renderHook(() => useEncounter());
+
+		expect(result.current.encounter.combatants).toHaveLength(1);
+		expect(result.current.encounter.roundNumber).toBe(2);
+		expect(result.current.isEmpty).toBe(false);
+	});
+
+	it("addCombatant adds a combatant with incremental IDs and persists", () => {
+		const { result } = renderHook(() => useEncounter());
+
+		act(() => result.current.addCombatant("Goblin"));
+		act(() => result.current.addCombatant("Orc"));
+
+		expect(result.current.encounter.combatants).toHaveLength(2);
+		expect(result.current.encounter.combatants[0].name).toBe("Goblin");
+		expect(result.current.encounter.combatants[1].name).toBe("Orc");
+		expect(result.current.isEmpty).toBe(false);
+		expect(mockSave).toHaveBeenCalled();
+	});
+
+	it("removeCombatant removes a combatant and persists", () => {
+		const { result } = renderHook(() => useEncounter());
+
+		act(() => result.current.addCombatant("Goblin"));
+		const id = result.current.encounter.combatants[0].id;
+
+		act(() => result.current.removeCombatant(id));
+
+		expect(result.current.encounter.combatants).toHaveLength(0);
+		expect(result.current.isEmpty).toBe(true);
+	});
+
+	it("advanceTurn and retreatTurn update encounter state", () => {
+		const { result } = renderHook(() => useEncounter());
+
+		act(() => result.current.addCombatant("Goblin"));
+		act(() => result.current.addCombatant("Orc"));
+
+		const initialActive = result.current.encounter.activeIndex;
+
+		act(() => result.current.advanceTurn());
+		expect(result.current.encounter.activeIndex).not.toBe(initialActive);
+
+		act(() => result.current.retreatTurn());
+		expect(result.current.encounter.activeIndex).toBe(initialActive);
+	});
+
+	it("clearEncounter resets to empty and resets ID counter", () => {
+		const { result } = renderHook(() => useEncounter());
+
+		act(() => result.current.addCombatant("Goblin"));
+		act(() => result.current.clearEncounter());
+
+		expect(result.current.encounter.combatants).toHaveLength(0);
+		expect(result.current.isEmpty).toBe(true);
+
+		// After clear, IDs restart from c-1
+		act(() => result.current.addCombatant("Orc"));
+		expect(result.current.encounter.combatants[0].id).toBe("c-1");
+	});
+
+	it("addCombatant with opts applies initiative, ac, maxHp", () => {
+		const { result } = renderHook(() => useEncounter());
+
+		act(() =>
+			result.current.addCombatant("Goblin", {
+				initiative: 15,
+				ac: 13,
+				maxHp: 7,
+			}),
+		);
+
+		const goblin = result.current.encounter.combatants[0];
+		expect(goblin.initiative).toBe(15);
+		expect(goblin.ac).toBe(13);
+		expect(goblin.maxHp).toBe(7);
+		expect(goblin.currentHp).toBe(7);
+	});
+
+	it("derived flags: hasCreatureCombatants and canRollAllInitiative", () => {
+		const { result } = renderHook(() => useEncounter());
+
+		// No creatures yet
+		expect(result.current.hasCreatureCombatants).toBe(false);
+		expect(result.current.canRollAllInitiative).toBe(false);
+
+		// Add from bestiary to get a creature combatant
+		const entry: BestiaryIndexEntry = {
+			name: "Goblin",
+			source: "MM",
+			ac: 15,
+			hp: 7,
+			dex: 14,
+			cr: "1/4",
+			initiativeProficiency: 0,
+			size: "Small",
+			type: "humanoid",
+		};
+
+		act(() => result.current.addFromBestiary(entry));
+
+		expect(result.current.hasCreatureCombatants).toBe(true);
+		expect(result.current.canRollAllInitiative).toBe(true);
+	});
+
+	it("addFromBestiary adds combatant with HP, AC, creatureId", () => {
+		const { result } = renderHook(() => useEncounter());
+
+		const entry: BestiaryIndexEntry = {
+			name: "Goblin",
+			source: "MM",
+			ac: 15,
+			hp: 7,
+			dex: 14,
+			cr: "1/4",
+			initiativeProficiency: 0,
+			size: "Small",
+			type: "humanoid",
+		};
+
+		act(() => result.current.addFromBestiary(entry));
+
+		const combatant = result.current.encounter.combatants[0];
+		expect(combatant.name).toBe("Goblin");
+		expect(combatant.maxHp).toBe(7);
+		expect(combatant.currentHp).toBe(7);
+		expect(combatant.ac).toBe(15);
+		expect(combatant.creatureId).toBe(creatureId("mm:goblin"));
+	});
+
+	it("addFromBestiary auto-numbers duplicate names", () => {
+		const { result } = renderHook(() => useEncounter());
+
+		const entry: BestiaryIndexEntry = {
+			name: "Goblin",
+			source: "MM",
+			ac: 15,
+			hp: 7,
+			dex: 14,
+			cr: "1/4",
+			initiativeProficiency: 0,
+			size: "Small",
+			type: "humanoid",
+		};
+
+		act(() => result.current.addFromBestiary(entry));
+		act(() => result.current.addFromBestiary(entry));
+
+		const names = result.current.encounter.combatants.map((c) => c.name);
+		expect(names).toContain("Goblin 1");
+		expect(names).toContain("Goblin 2");
+	});
+
+	it("addFromPlayerCharacter adds combatant with HP, AC, color, icon", () => {
+		const { result } = renderHook(() => useEncounter());
+
+		const pc: PlayerCharacter = {
+			id: playerCharacterId("pc-1"),
+			name: "Aria",
+			ac: 16,
+			maxHp: 30,
+			color: "blue",
+			icon: "sword",
+		};
+
+		act(() => result.current.addFromPlayerCharacter(pc));
+
+		const combatant = result.current.encounter.combatants[0];
+		expect(combatant.name).toBe("Aria");
+		expect(combatant.maxHp).toBe(30);
+		expect(combatant.currentHp).toBe(30);
+		expect(combatant.ac).toBe(16);
+		expect(combatant.color).toBe("blue");
+		expect(combatant.icon).toBe("sword");
+		expect(combatant.playerCharacterId).toBe(playerCharacterId("pc-1"));
+	});
+});
diff --git a/apps/web/src/hooks/__tests__/use-player-characters.test.ts b/apps/web/src/hooks/__tests__/use-player-characters.test.ts
new file mode 100644
index 0000000..4281fd6
--- /dev/null
+++ b/apps/web/src/hooks/__tests__/use-player-characters.test.ts
@@ -0,0 +1,100 @@
+// @vitest-environment jsdom
+import { playerCharacterId } from "@initiative/domain";
+import { act, renderHook } from "@testing-library/react";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import { usePlayerCharacters } from "../use-player-characters.js";
+
+vi.mock("../../persistence/player-character-storage.js", () => ({
+	loadPlayerCharacters: vi.fn().mockReturnValue([]),
+	savePlayerCharacters: vi.fn(),
+}));
+
+const { loadPlayerCharacters: mockLoad, savePlayerCharacters: mockSave } =
+	await vi.importMock<
+		typeof import("../../persistence/player-character-storage.js")
+	>("../../persistence/player-character-storage.js");
+
+describe("usePlayerCharacters", () => {
+	beforeEach(() => {
+		vi.clearAllMocks();
+		mockLoad.mockReturnValue([]);
+	});
+
+	it("initializes with characters from persistence", () => {
+		const stored = [
+			{
+				id: playerCharacterId("pc-1"),
+				name: "Aria",
+				ac: 16,
+				maxHp: 30,
+				color: undefined,
+				icon: undefined,
+			},
+		];
+		mockLoad.mockReturnValue(stored);
+
+		const { result } = renderHook(() => usePlayerCharacters());
+
+		expect(result.current.characters).toEqual(stored);
+	});
+
+	it("createCharacter adds a character and persists", () => {
+		const { result } = renderHook(() => usePlayerCharacters());
+
+		act(() => {
+			result.current.createCharacter("Vex", 15, 28, undefined, undefined);
+		});
+
+		expect(result.current.characters).toHaveLength(1);
+		expect(result.current.characters[0].name).toBe("Vex");
+		expect(result.current.characters[0].ac).toBe(15);
+		expect(result.current.characters[0].maxHp).toBe(28);
+		expect(mockSave).toHaveBeenCalled();
+	});
+
+	it("createCharacter returns domain error for empty name", () => {
+		const { result } = renderHook(() => usePlayerCharacters());
+
+		let error: unknown;
+		act(() => {
+			error = result.current.createCharacter("", 15, 28, undefined, undefined);
+		});
+
+		expect(error).toMatchObject({ kind: "domain-error" });
+		expect(result.current.characters).toHaveLength(0);
+	});
+
+	it("editCharacter updates character and persists", () => {
+		const { result } = renderHook(() => usePlayerCharacters());
+
+		act(() => {
+			result.current.createCharacter("Vex", 15, 28, undefined, undefined);
+		});
+
+		const id = result.current.characters[0].id;
+
+		act(() => {
+			result.current.editCharacter(id, { name: "Vex'ahlia" });
+		});
+
+		expect(result.current.characters[0].name).toBe("Vex'ahlia");
+		expect(mockSave).toHaveBeenCalled();
+	});
+
+	it("deleteCharacter removes character and persists", () => {
+		const { result } = renderHook(() => usePlayerCharacters());
+
+		act(() => {
+			result.current.createCharacter("Vex", 15, 28, undefined, undefined);
+		});
+
+		const id = result.current.characters[0].id;
+
+		act(() => {
+			result.current.deleteCharacter(id);
+		});
+
+		expect(result.current.characters).toHaveLength(0);
+		expect(mockSave).toHaveBeenCalled();
+	});
+});
diff --git a/apps/web/src/hooks/__tests__/use-side-panel-state.test.ts b/apps/web/src/hooks/__tests__/use-side-panel-state.test.ts
new file mode 100644
index 0000000..2fdc9ff
--- /dev/null
+++ b/apps/web/src/hooks/__tests__/use-side-panel-state.test.ts
@@ -0,0 +1,159 @@
+// @vitest-environment jsdom
+import { creatureId } from "@initiative/domain";
+import { act, renderHook } from "@testing-library/react";
+import { describe, expect, it, vi } from "vitest";
+import { useSidePanelState } from "../use-side-panel-state.js";
+
+function mockMatchMedia(matches: boolean) {
+	const listeners: Array<(e: MediaQueryListEvent) => void> = [];
+	const mql = {
+		matches,
+		addEventListener: vi.fn(
+			(_event: string, handler: (e: MediaQueryListEvent) => void) => {
+				listeners.push(handler);
+			},
+		),
+		removeEventListener: vi.fn(),
+	};
+	globalThis.matchMedia = vi.fn().mockReturnValue(mql) as typeof matchMedia;
+	return { mql, listeners };
+}
+
+const CREATURE_A = creatureId("creature-a");
+
+describe("useSidePanelState", () => {
+	it("starts with closed panel, no selection, not collapsed", () => {
+		mockMatchMedia(false);
+		const { result } = renderHook(() => useSidePanelState());
+
+		expect(result.current.panelView).toEqual({ mode: "closed" });
+		expect(result.current.selectedCreatureId).toBeNull();
+		expect(result.current.isRightPanelCollapsed).toBe(false);
+		expect(result.current.bulkImportMode).toBe(false);
+		expect(result.current.sourceManagerMode).toBe(false);
+		expect(result.current.pinnedCreatureId).toBeNull();
+	});
+
+	it("showCreature sets creature mode and selectedCreatureId", () => {
+		mockMatchMedia(false);
+		const { result } = renderHook(() => useSidePanelState());
+
+		act(() => result.current.showCreature(CREATURE_A));
+
+		expect(result.current.panelView).toEqual({
+			mode: "creature",
+			creatureId: CREATURE_A,
+		});
+		expect(result.current.selectedCreatureId).toBe(CREATURE_A);
+	});
+
+	it("showBulkImport sets bulk-import mode, selectedCreatureId null", () => {
+		mockMatchMedia(false);
+		const { result } = renderHook(() => useSidePanelState());
+
+		act(() => result.current.showBulkImport());
+
+		expect(result.current.panelView).toEqual({ mode: "bulk-import" });
+		expect(result.current.selectedCreatureId).toBeNull();
+		expect(result.current.bulkImportMode).toBe(true);
+	});
+
+	it("showSourceManager sets source-manager mode", () => {
+		mockMatchMedia(false);
+		const { result } = renderHook(() => useSidePanelState());
+
+		act(() => result.current.showSourceManager());
+
+		expect(result.current.panelView).toEqual({ mode: "source-manager" });
+		expect(result.current.sourceManagerMode).toBe(true);
+	});
+
+	it("dismissPanel sets mode to closed", () => {
+		mockMatchMedia(false);
+		const { result } = renderHook(() => useSidePanelState());
+
+		act(() => result.current.showCreature(CREATURE_A));
+		act(() => result.current.dismissPanel());
+
+		expect(result.current.panelView).toEqual({ mode: "closed" });
+	});
+
+	it("toggleCollapse flips isRightPanelCollapsed", () => {
+		mockMatchMedia(false);
+		const { result } = renderHook(() => useSidePanelState());
+
+		expect(result.current.isRightPanelCollapsed).toBe(false);
+
+		act(() => result.current.toggleCollapse());
+		expect(result.current.isRightPanelCollapsed).toBe(true);
+
+		act(() => result.current.toggleCollapse());
+		expect(result.current.isRightPanelCollapsed).toBe(false);
+	});
+
+	it("showCreature resets collapse state", () => {
+		mockMatchMedia(false);
+		const { result } = renderHook(() => useSidePanelState());
+
+		act(() => result.current.toggleCollapse());
+		expect(result.current.isRightPanelCollapsed).toBe(true);
+
+		act(() => result.current.showCreature(CREATURE_A));
+		expect(result.current.isRightPanelCollapsed).toBe(false);
+	});
+
+	it("togglePin pins the selected creature", () => {
+		mockMatchMedia(false);
+		const { result } = renderHook(() => useSidePanelState());
+
+		act(() => result.current.showCreature(CREATURE_A));
+		act(() => result.current.togglePin());
+
+		expect(result.current.pinnedCreatureId).toBe(CREATURE_A);
+	});
+
+	it("togglePin unpins when already pinned to same creature", () => {
+		mockMatchMedia(false);
+		const { result } = renderHook(() => useSidePanelState());
+
+		act(() => result.current.showCreature(CREATURE_A));
+		act(() => result.current.togglePin());
+		act(() => result.current.togglePin());
+
+		expect(result.current.pinnedCreatureId).toBeNull();
+	});
+
+	it("togglePin does nothing when no creature is selected", () => {
+		mockMatchMedia(false);
+		const { result } = renderHook(() => useSidePanelState());
+
+		act(() => result.current.togglePin());
+
+		expect(result.current.pinnedCreatureId).toBeNull();
+	});
+
+	it("unpin clears pinned creature", () => {
+		mockMatchMedia(false);
+		const { result } = renderHook(() => useSidePanelState());
+
+		act(() => result.current.showCreature(CREATURE_A));
+		act(() => result.current.togglePin());
+		act(() => result.current.unpin());
+
+		expect(result.current.pinnedCreatureId).toBeNull();
+	});
+
+	it("isWideDesktop reflects matchMedia result", () => {
+		mockMatchMedia(true);
+		const { result } = renderHook(() => useSidePanelState());
+
+		expect(result.current.isWideDesktop).toBe(true);
+	});
+
+	it("isWideDesktop is false on narrow viewport", () => {
+		mockMatchMedia(false);
+		const { result } = renderHook(() => useSidePanelState());
+
+		expect(result.current.isWideDesktop).toBe(false);
+	});
+});