diff --git a/src/__tests__/BerlinClock.test.tsx b/src/__tests__/BerlinClock.test.tsx
index f30e9d2..ff10d83 100644
--- a/src/__tests__/BerlinClock.test.tsx
+++ b/src/__tests__/BerlinClock.test.tsx
@@ -1,54 +1,61 @@
-import { render, screen } from '@testing-library/react';
-import { BerlinClock } from '../containers/BerlinClock';
-import { LampState } from '../types';
+import { render, screen } from "@testing-library/react";
+import { BerlinClock } from "../containers/BerlinClock";
+import { LampState } from "../types";
 
-describe('BerlinClock', () => {
+describe("BerlinClock", () => {
   const testClock = {
     secondsRow: [LampState.Y],
     fiveHours: [LampState.R, LampState.R, LampState.R, LampState.O],
     oneHour: [LampState.R, LampState.R, LampState.R, LampState.R],
     fiveMinutes: [
-      LampState.Y, LampState.Y, LampState.R,
-      LampState.Y, LampState.Y, LampState.R,
-      LampState.O, LampState.O, LampState.O,
-      LampState.O, LampState.O,
+      LampState.Y,
+      LampState.Y,
+      LampState.R,
+      LampState.Y,
+      LampState.Y,
+      LampState.R,
+      LampState.O,
+      LampState.O,
+      LampState.O,
+      LampState.O,
+      LampState.O,
     ],
     oneMinute: [LampState.O, LampState.O, LampState.O, LampState.O],
   };
 
-  it('renders nothing when disabled', () => {
-    const { container } = render(<BerlinClock enabled={false} clock={testClock} />);
-    expect(container.innerHTML).toBe('');
+  it("renders nothing when disabled", () => {
+    const { container } = render(
+      <BerlinClock enabled={false} clock={testClock} />,
+    );
+    expect(container.innerHTML).toBe("");
   });
 
-  it('renders all five rows when enabled', () => {
+  it("renders all five rows when enabled", () => {
     render(<BerlinClock enabled={true} clock={testClock} />);
 
-    expect(screen.getByTestId('seconds-row')).toBeInTheDocument();
-    expect(screen.getByTestId('five-hours-row')).toBeInTheDocument();
-    expect(screen.getByTestId('single-hours-row')).toBeInTheDocument();
-    expect(screen.getByTestId('five-minutes-row')).toBeInTheDocument();
-    expect(screen.getByTestId('single-minutes-row')).toBeInTheDocument();
+    expect(screen.getByTestId("seconds-row")).toBeInTheDocument();
+    expect(screen.getByTestId("five-hours-row")).toBeInTheDocument();
+    expect(screen.getByTestId("single-hours-row")).toBeInTheDocument();
+    expect(screen.getByTestId("five-minutes-row")).toBeInTheDocument();
+    expect(screen.getByTestId("single-minutes-row")).toBeInTheDocument();
   });
 
-  it('renders the correct number of lamps in seconds-row', () => {
+  it("renders the correct number of lamps in seconds-row", () => {
     render(<BerlinClock enabled={true} clock={testClock} />);
-    const secRow = screen.getByTestId('seconds-row');
-    const lampLine = secRow.querySelector('[data-testid="lamp-line"]');
-    expect(lampLine?.children).toHaveLength(1);
+    const secRow = screen.getByTestId("seconds-row");
+    expect(secRow.children).toHaveLength(1);
   });
 
-  it('renders the correct number of lamps in five-hours-row', () => {
+  it("renders the correct number of lamps in five-hours-row", () => {
     render(<BerlinClock enabled={true} clock={testClock} />);
-    const row = screen.getByTestId('five-hours-row');
-    const lampLine = row.querySelector('[data-testid="lamp-line"]');
-    expect(lampLine?.children).toHaveLength(4);
+    const row = screen.getByTestId("five-hours-row");
+    expect(row.children).toHaveLength(4);
   });
 
-  it('renders correct aria-labels in the seconds lamp', () => {
+  it("renders correct aria-labels in the seconds lamp", () => {
     render(<BerlinClock enabled={true} clock={testClock} />);
-    const secRow = screen.getByTestId('seconds-row');
-    const span = secRow.querySelector('span');
-    expect(span).toHaveAttribute('aria-label', 'Y');
+    const secRow = screen.getByTestId("seconds-row");
+    const span = secRow.querySelector("span");
+    expect(span).toHaveAttribute("aria-label", "Y");
   });
 });
diff --git a/src/__tests__/DigitalClock.test.tsx b/src/__tests__/DigitalClock.test.tsx
index 20e53f5..8c6b710 100644
--- a/src/__tests__/DigitalClock.test.tsx
+++ b/src/__tests__/DigitalClock.test.tsx
@@ -1,20 +1,20 @@
-import { render, screen, fireEvent } from '@testing-library/react';
-import { DigitalClock } from '../containers/DigitalClock';
-import * as utils from '../utils';
+import { render, screen, fireEvent } from "@testing-library/react";
+import { DigitalClock } from "../containers/DigitalClock";
+import * as utils from "../utils";
 
-vi.mock('../utils');
+vi.mock("../utils");
 
 const mockedDateToDigital = vi.mocked(utils.dateToDigital);
 const mockedDigitalToDate = vi.mocked(utils.digitalToDate);
 
-describe('DigitalClock', () => {
+describe("DigitalClock", () => {
   const onTimeChangeMock = vi.fn();
 
   beforeEach(() => {
     vi.clearAllMocks();
-    mockedDateToDigital.mockReturnValue('14:30:15');
+    mockedDateToDigital.mockReturnValue("14:30:15");
     mockedDigitalToDate.mockImplementation((str: string) => {
-      const parts = str.split(':');
+      const parts = str.split(":");
       if (parts.length !== 3) return new Date(NaN);
       const [h, m, s] = parts.map(Number);
       if (isNaN(h) || isNaN(m) || isNaN(s)) return new Date(NaN);
@@ -24,58 +24,58 @@ describe('DigitalClock', () => {
     });
   });
 
-  it('renders nothing when disabled', () => {
+  it("renders nothing when disabled", () => {
     const { container } = render(
       <DigitalClock
         enabled={false}
-        currentTime={new Date(2025,0,1,14,30,15)}
+        currentTime={new Date(2025, 0, 1, 14, 30, 15)}
         onTimeChange={onTimeChangeMock}
       />,
     );
-    expect(container.innerHTML).toBe('');
+    expect(container.innerHTML).toBe("");
   });
 
-  it('renders the digital time and input when enabled', () => {
+  it("renders the digital time and input when enabled", () => {
     render(
       <DigitalClock
         enabled={true}
-        currentTime={new Date(2025,0,1,14,30,15)}
+        currentTime={new Date(2025, 0, 1, 14, 30, 15)}
         onTimeChange={onTimeChangeMock}
       />,
     );
-    expect(screen.getByTestId('digital-clock')).toHaveTextContent('14:30:15');
-    expect(screen.getByTestId('time-input')).toBeInTheDocument();
+    expect(screen.getByTestId("digital-clock")).toHaveTextContent("14:30:15");
+    expect(screen.getByTestId("time-input")).toBeInTheDocument();
   });
 
-  it('calls onTimeChange when a valid time is entered', () => {
+  it("calls onTimeChange when a valid time is entered", () => {
     render(
       <DigitalClock
         enabled={true}
-        currentTime={new Date(2025,0,1,14,30,15)}
+        currentTime={new Date(2025, 0, 1, 14, 30, 15)}
         onTimeChange={onTimeChangeMock}
       />,
     );
-    const input = screen.getByTestId('time-input');
-    fireEvent.change(input, { target: { value: '12:00:00' } });
+    const input = screen.getByTestId("time-input");
+    fireEvent.change(input, { target: { value: "12:00:00" } });
 
     expect(onTimeChangeMock).toHaveBeenCalledTimes(1);
     const expectedDate = new Date(2025, 0, 1, 12, 0, 0, 0);
     expect(onTimeChangeMock).toHaveBeenCalledWith(expectedDate);
 
-    expect(input).toHaveValue('12:00:00');
+    expect(input).toHaveValue("12:00:00");
   });
 
-  it('does not call onTimeChange when an invalid time is entered', () => {
+  it("does not call onTimeChange when an invalid time is entered", () => {
     render(
       <DigitalClock
         enabled={true}
-        currentTime={new Date(2025,0,1,14,30,15)}
+        currentTime={new Date(2025, 0, 1, 14, 30, 15)}
         onTimeChange={onTimeChangeMock}
       />,
     );
-    const input = screen.getByTestId('time-input');
-    fireEvent.change(input, { target: { value: 'notatime' } });
+    const input = screen.getByTestId("time-input");
+    fireEvent.change(input, { target: { value: "notatime" } });
     expect(onTimeChangeMock).not.toHaveBeenCalled();
-    expect(input).toHaveValue('notatime');
+    expect(input).toHaveValue("notatime");
   });
 });
diff --git a/src/__tests__/Lamp.test.tsx b/src/__tests__/Lamp.test.tsx
index 96495b1..fcb839f 100644
--- a/src/__tests__/Lamp.test.tsx
+++ b/src/__tests__/Lamp.test.tsx
@@ -1,22 +1,22 @@
-import { render } from '@testing-library/react';
-import { Lamp } from '../components/Lamp';
-import { LampState } from '../types';
+import { render } from "@testing-library/react";
+import { Lamp } from "../components/Lamp";
+import { LampState } from "../types";
 
-describe('Lamp', () => {
-  it('renders without crashing', () => {
+describe("Lamp", () => {
+  it("renders without crashing", () => {
     render(<Lamp state={LampState.Y} />);
     // If it doesn't throw, we're good.
   });
 
   it.each([
-    ['Y' as LampState, 'Y'],
-    ['R' as LampState, 'R'],
-    ['O' as LampState, 'O'],
-    ['N' as LampState, 'N'],
+    ["Y" as LampState, "Y"],
+    ["R" as LampState, "R"],
+    ["O" as LampState, "O"],
+    ["N" as LampState, "N"],
   ])('displays aria-label "%s" for state %s', (state, expectedLabel) => {
     const { container } = render(<Lamp state={state} />);
     // The root element should have the correct aria-label
     const lampElement = container.firstChild as HTMLElement;
-    expect(lampElement).toHaveAttribute('aria-label', expectedLabel);
+    expect(lampElement).toHaveAttribute("aria-label", expectedLabel);
   });
 });
diff --git a/src/__tests__/LampLine.test.tsx b/src/__tests__/LampLine.test.tsx
index 77dbec3..7264838 100644
--- a/src/__tests__/LampLine.test.tsx
+++ b/src/__tests__/LampLine.test.tsx
@@ -1,33 +1,33 @@
-import { render, screen } from '@testing-library/react';
-import { LampLine } from '../components/LampLine';
-import { LampState } from '../types';
+import { render, screen } from "@testing-library/react";
+import { LampLine } from "../components/LampLine";
+import { LampState } from "../types";
 
-describe('LampLine', () => {
-  it('renders without crashing', () => {
+describe("LampLine", () => {
+  it("renders without crashing", () => {
     render(<LampLine states={[]} />);
   });
 
-  it('renders the correct number of lamps', () => {
+  it("renders the correct number of lamps", () => {
     const states = [LampState.Y, LampState.R, LampState.O];
     render(<LampLine states={states} />);
-    const container = screen.getByTestId('lamp-line');
+    const container = screen.getByTestId("lamp-line");
     expect(container.children).toHaveLength(states.length);
   });
 
-  it('displays correct aria-labels for each lamp', () => {
+  it("displays correct aria-labels for each lamp", () => {
     const states = [LampState.Y, LampState.R, LampState.O, LampState.N];
     render(<LampLine states={states} />);
-    const container = screen.getByTestId('lamp-line');
-    const lampSpans = container.querySelectorAll('span');
+    const container = screen.getByTestId("lamp-line");
+    const lampSpans = container.querySelectorAll("span");
     expect(lampSpans).toHaveLength(states.length);
     lampSpans.forEach((span, index) => {
-      expect(span).toHaveAttribute('aria-label', states[index]);
+      expect(span).toHaveAttribute("aria-label", states[index]);
     });
   });
 
-  it('renders no lamps when given an empty array', () => {
+  it("renders no lamps when given an empty array", () => {
     render(<LampLine states={[]} />);
-    const container = screen.getByTestId('lamp-line');
+    const container = screen.getByTestId("lamp-line");
     expect(container.children).toHaveLength(0);
   });
 });
diff --git a/src/__tests__/TimeConverter.test.tsx b/src/__tests__/TimeConverter.test.tsx
index db0d02b..12198ae 100644
--- a/src/__tests__/TimeConverter.test.tsx
+++ b/src/__tests__/TimeConverter.test.tsx
@@ -1,18 +1,29 @@
-import { render, screen, fireEvent } from '@testing-library/react';
-import { TimeConverter } from '../containers/TimeConverter';
-import { useCurrentTime } from '../hooks/useCurrentTime';
+import { render, screen, fireEvent } from "@testing-library/react";
+import { TimeConverter } from "../containers/TimeConverter";
+import { useCurrentTime } from "../hooks/useCurrentTime";
 
-vi.mock('../hooks/useCurrentTime');
-vi.mock('../containers/BerlinClock', () => ({
+vi.mock("../hooks/useCurrentTime");
+vi.mock("../containers/BerlinClock", () => ({
   BerlinClock: ({ enabled }: { enabled: boolean }) => (
-    <div data-testid="berlin-clock">{enabled ? 'enabled' : 'disabled'}</div>
+    <div data-testid="berlin-clock">{enabled ? "enabled" : "disabled"}</div>
   ),
 }));
-vi.mock('../containers/DigitalClock', () => ({
-  DigitalClock: ({ enabled, currentTime, onTimeChange }: { enabled: boolean; currentTime: Date; onTimeChange: (d: Date) => void }) => (
+vi.mock("../containers/DigitalClock", () => ({
+  DigitalClock: ({
+    enabled,
+    currentTime,
+    onTimeChange,
+  }: {
+    enabled: boolean;
+    currentTime: Date;
+    onTimeChange: (d: Date) => void;
+  }) => (
     <div data-testid="digital-clock-wrapper">
       <span data-testid="digital-clock-time">{currentTime.toISOString()}</span>
-      <button data-testid="set-time" onClick={() => onTimeChange(new Date(2025,0,1,12,0,0))}>
+      <button
+        data-testid="set-time"
+        onClick={() => onTimeChange(new Date(2025, 0, 1, 12, 0, 0))}
+      >
         Set time
       </button>
       {!enabled && <span data-testid="disabled-indicator">disabled</span>}
@@ -22,7 +33,7 @@ vi.mock('../containers/DigitalClock', () => ({
 
 const mockedUseCurrentTime = vi.mocked(useCurrentTime);
 
-describe('TimeConverter', () => {
+describe("TimeConverter", () => {
   const setCurrentTimeMock = vi.fn();
   const baseDate = new Date(2025, 0, 1, 14, 30, 15);
 
@@ -34,23 +45,25 @@ describe('TimeConverter', () => {
     });
   });
 
-  it('renders the checkbox, BerlinClock, and DigitalClock', () => {
+  it("renders the checkbox, BerlinClock, and DigitalClock", () => {
     render(<TimeConverter />);
-    expect(screen.getByTestId('use-system-time')).toBeInTheDocument();
-    expect(screen.getByTestId('berlin-clock')).toHaveTextContent('enabled');
-    expect(screen.getByTestId('digital-clock-wrapper')).toBeInTheDocument();
+    expect(screen.getByTestId("use-system-time")).toBeInTheDocument();
+    expect(screen.getByTestId("berlin-clock")).toHaveTextContent("enabled");
+    expect(screen.getByTestId("digital-clock-wrapper")).toBeInTheDocument();
   });
 
-  it('disables both clocks when checkbox is checked', () => {
+  it("disables both clocks when checkbox is checked", () => {
     render(<TimeConverter />);
-    fireEvent.click(screen.getByTestId('use-system-time'));
-    expect(screen.getByTestId('berlin-clock')).toHaveTextContent('disabled');
-    expect(screen.getByTestId('disabled-indicator')).toBeInTheDocument();
+    fireEvent.click(screen.getByTestId("use-system-time"));
+    expect(screen.getByTestId("berlin-clock")).toHaveTextContent("disabled");
+    expect(screen.getByTestId("disabled-indicator")).toBeInTheDocument();
   });
 
-  it('calls setCurrentTime when DigitalClock triggers onTimeChange', () => {
+  it("calls setCurrentTime when DigitalClock triggers onTimeChange", () => {
     render(<TimeConverter />);
-    fireEvent.click(screen.getByTestId('set-time'));
-    expect(setCurrentTimeMock).toHaveBeenCalledWith(new Date(2025, 0, 1, 12, 0, 0));
+    fireEvent.click(screen.getByTestId("set-time"));
+    expect(setCurrentTimeMock).toHaveBeenCalledWith(
+      new Date(2025, 0, 1, 12, 0, 0),
+    );
   });
 });
diff --git a/src/__tests__/useCurrentTime.test.ts b/src/__tests__/useCurrentTime.test.ts
index 5348220..d625fc5 100644
--- a/src/__tests__/useCurrentTime.test.ts
+++ b/src/__tests__/useCurrentTime.test.ts
@@ -1,10 +1,10 @@
-import { renderHook, act } from '@testing-library/react';
-import { useCurrentTime } from '../hooks/useCurrentTime';
+import { renderHook } from "@testing-library/react";
+import { useCurrentTime } from "../hooks/useCurrentTime";
 
-describe('useCurrentTime', () => {
-  it('returns a date and setter', () => {
+describe("useCurrentTime", () => {
+  it("returns a date and setter", () => {
     const { result } = renderHook(() => useCurrentTime());
     expect(result.current.currentTime).toBeInstanceOf(Date);
-    expect(typeof result.current.setCurrentTime).toBe('function');
+    expect(typeof result.current.setCurrentTime).toBe("function");
   });
 });
diff --git a/src/__tests__/utils.test.ts b/src/__tests__/utils.test.ts
index 359c697..264035a 100644
--- a/src/__tests__/utils.test.ts
+++ b/src/__tests__/utils.test.ts
@@ -1,86 +1,157 @@
-import { dateToDigital, digitalToDate, dateToBerlin, berlinToDate } from '../utils';
-import { LampState } from '../types';
+import {
+  dateToDigital,
+  digitalToDate,
+  dateToBerlin,
+  berlinToDate,
+} from "../utils";
+import { LampState } from "../types";
 
-describe('Utils', () => {
-  describe('dateToDigital', () => {
+describe("Utils", () => {
+  describe("dateToDigital", () => {
     it('returns "HH:mm:ss" for a given date', () => {
       const date = new Date(2025, 0, 1, 14, 5, 9);
-      expect(dateToDigital(date)).toBe('14:05:09');
+      expect(dateToDigital(date)).toBe("14:05:09");
     });
 
-    it('pads single-digit hours, minutes, seconds', () => {
+    it("pads single-digit hours, minutes, seconds", () => {
       const date = new Date(2025, 0, 1, 2, 3, 4);
-      expect(dateToDigital(date)).toBe('02:03:04');
+      expect(dateToDigital(date)).toBe("02:03:04");
     });
   });
 
-  describe('digitalToDate', () => {
-    it('parses a valid digital string', () => {
-      const result = digitalToDate('12:34:56');
+  describe("digitalToDate", () => {
+    it("parses a valid digital string", () => {
+      const result = digitalToDate("12:34:56");
       expect(result).toBeInstanceOf(Date);
       expect(result.getHours()).toBe(12);
       expect(result.getMinutes()).toBe(34);
       expect(result.getSeconds()).toBe(56);
     });
 
-    it('returns an invalid date for invalid input', () => {
-      const result = digitalToDate('abc');
+    it("returns an invalid date for invalid input", () => {
+      const result = digitalToDate("abc");
       expect(isNaN(result.getTime())).toBe(true);
     });
   });
 
-  describe('dateToBerlin', () => {
+  describe("dateToBerlin", () => {
     const makeTime = (h: number, m: number, s: number) => {
       const d = new Date(2025, 0, 1, h, m, s);
       return d;
     };
 
-    it('returns correct clock for 00:00:00', () => {
+    it("returns correct clock for 00:00:00", () => {
       const clock = dateToBerlin(makeTime(0, 0, 0));
       expect(clock.secondsRow).toEqual([LampState.Y]);
-      expect(clock.fiveHours).toEqual([LampState.O, LampState.O, LampState.O, LampState.O]);
-      expect(clock.oneHour).toEqual([LampState.O, LampState.O, LampState.O, LampState.O]);
-      expect(clock.fiveMinutes).toEqual([
-        LampState.O, LampState.O, LampState.O,
-        LampState.O, LampState.O, LampState.O,
-        LampState.O, LampState.O, LampState.O,
-        LampState.O, LampState.O,
+      expect(clock.fiveHours).toEqual([
+        LampState.O,
+        LampState.O,
+        LampState.O,
+        LampState.O,
+      ]);
+      expect(clock.oneHour).toEqual([
+        LampState.O,
+        LampState.O,
+        LampState.O,
+        LampState.O,
+      ]);
+      expect(clock.fiveMinutes).toEqual([
+        LampState.O,
+        LampState.O,
+        LampState.O,
+        LampState.O,
+        LampState.O,
+        LampState.O,
+        LampState.O,
+        LampState.O,
+        LampState.O,
+        LampState.O,
+        LampState.O,
+      ]);
+      expect(clock.oneMinute).toEqual([
+        LampState.O,
+        LampState.O,
+        LampState.O,
+        LampState.O,
       ]);
-      expect(clock.oneMinute).toEqual([LampState.O, LampState.O, LampState.O, LampState.O]);
     });
 
-    it('returns correct clock for 23:59:59', () => {
+    it("returns correct clock for 23:59:59", () => {
       const clock = dateToBerlin(makeTime(23, 59, 59));
       expect(clock.secondsRow).toEqual([LampState.O]);
-      expect(clock.fiveHours).toEqual([LampState.R, LampState.R, LampState.R, LampState.R]);
-      expect(clock.oneHour).toEqual([LampState.R, LampState.R, LampState.R, LampState.O]);
-      expect(clock.fiveMinutes).toEqual([
-        LampState.Y, LampState.Y, LampState.R,
-        LampState.Y, LampState.Y, LampState.R,
-        LampState.Y, LampState.Y, LampState.R,
-        LampState.Y, LampState.Y,
+      expect(clock.fiveHours).toEqual([
+        LampState.R,
+        LampState.R,
+        LampState.R,
+        LampState.R,
+      ]);
+      expect(clock.oneHour).toEqual([
+        LampState.R,
+        LampState.R,
+        LampState.R,
+        LampState.O,
+      ]);
+      expect(clock.fiveMinutes).toEqual([
+        LampState.Y,
+        LampState.Y,
+        LampState.R,
+        LampState.Y,
+        LampState.Y,
+        LampState.R,
+        LampState.Y,
+        LampState.Y,
+        LampState.R,
+        LampState.Y,
+        LampState.Y,
+      ]);
+      expect(clock.oneMinute).toEqual([
+        LampState.Y,
+        LampState.Y,
+        LampState.Y,
+        LampState.Y,
       ]);
-      expect(clock.oneMinute).toEqual([LampState.Y, LampState.Y, LampState.Y, LampState.Y]);
     });
 
-    it('returns correct clock for 12:34:00', () => {
+    it("returns correct clock for 12:34:00", () => {
       const clock = dateToBerlin(makeTime(12, 34, 0));
       expect(clock.secondsRow).toEqual([LampState.Y]);
-      expect(clock.fiveHours).toEqual([LampState.R, LampState.R, LampState.O, LampState.O]);
-      expect(clock.oneHour).toEqual([LampState.R, LampState.R, LampState.O, LampState.O]);
+      expect(clock.fiveHours).toEqual([
+        LampState.R,
+        LampState.R,
+        LampState.O,
+        LampState.O,
+      ]);
+      expect(clock.oneHour).toEqual([
+        LampState.R,
+        LampState.R,
+        LampState.O,
+        LampState.O,
+      ]);
       const expectedFiveMinutes = [
-        LampState.Y, LampState.Y, LampState.R,
-        LampState.Y, LampState.Y, LampState.R,
-        LampState.O, LampState.O, LampState.O,
-        LampState.O, LampState.O,
+        LampState.Y,
+        LampState.Y,
+        LampState.R,
+        LampState.Y,
+        LampState.Y,
+        LampState.R,
+        LampState.O,
+        LampState.O,
+        LampState.O,
+        LampState.O,
+        LampState.O,
       ];
       expect(clock.fiveMinutes).toEqual(expectedFiveMinutes);
-      expect(clock.oneMinute).toEqual([LampState.Y, LampState.Y, LampState.Y, LampState.Y]);
+      expect(clock.oneMinute).toEqual([
+        LampState.Y,
+        LampState.Y,
+        LampState.Y,
+        LampState.Y,
+      ]);
     });
   });
 
-  describe('berlinToDate', () => {
-    it('roundtrips correctly: dateToBerlin then berlinToDate returns the original date (seconds floor to even)', () => {
+  describe("berlinToDate", () => {
+    it("roundtrips correctly: dateToBerlin then berlinToDate returns the original date (seconds floor to even)", () => {
       const original = new Date(2025, 0, 1, 14, 30, 0);
       const clock = dateToBerlin(original);
       const result = berlinToDate(clock);
@@ -89,7 +160,7 @@ describe('Utils', () => {
       expect(result.getSeconds()).toBe(0);
     });
 
-    it('roundtrips with odd seconds: result seconds will be zero (only parity stored)', () => {
+    it("roundtrips with odd seconds: result seconds will be zero (only parity stored)", () => {
       const original = new Date(2025, 0, 1, 23, 59, 59);
       const clock = dateToBerlin(original);
       const result = berlinToDate(clock);
@@ -98,16 +169,23 @@ describe('Utils', () => {
       expect(result.getSeconds()).toBe(0);
     });
 
-    it('converts a known Berlin clock to the correct time', () => {
+    it("converts a known Berlin clock to the correct time", () => {
       const clock = {
         secondsRow: [LampState.Y],
         fiveHours: [LampState.R, LampState.R, LampState.O, LampState.O],
         oneHour: [LampState.R, LampState.R, LampState.O, LampState.O],
         fiveMinutes: [
-          LampState.Y, LampState.Y, LampState.R,
-          LampState.Y, LampState.Y, LampState.R,
-          LampState.O, LampState.O, LampState.O,
-          LampState.O, LampState.O,
+          LampState.Y,
+          LampState.Y,
+          LampState.R,
+          LampState.Y,
+          LampState.Y,
+          LampState.R,
+          LampState.O,
+          LampState.O,
+          LampState.O,
+          LampState.O,
+          LampState.O,
         ],
         oneMinute: [LampState.Y, LampState.Y, LampState.Y, LampState.Y],
       };
diff --git a/src/components/Lamp.tsx b/src/components/Lamp.tsx
index 84e56b6..2ee0f57 100644
--- a/src/components/Lamp.tsx
+++ b/src/components/Lamp.tsx
@@ -1,10 +1,41 @@
-import { LampState } from '../types';
+import React from "react";
+import { LampState } from "../types";
 
 interface LampProps {
   state: LampState;
   id?: string;
+  variant?: "alone" | "first" | "last" | "middle";
 }
 
-export function Lamp({ state, id }: LampProps) {
-  return <span data-testid={id} aria-label={state} />;
+function getBackgroundColor(state: LampState): string {
+  if (state === LampState.R) return "#ff3333";
+  if (state === LampState.Y) return "#ffcc00";
+  return "#333";
+}
+
+function getBorderRadius(variant?: LampProps["variant"]): string {
+  switch (variant) {
+    case "alone":
+      return "50%";
+    case "first":
+      return "50% 0 0 50%";
+    case "last":
+      return "0 50% 50% 0";
+    default:
+      return "0";
+  }
+}
+
+export function Lamp({ state, id, variant }: LampProps) {
+  const style: React.CSSProperties = {
+    display: "inline-block",
+    width: 20,
+    height: 20,
+    backgroundColor: getBackgroundColor(state),
+    borderRadius: getBorderRadius(variant),
+    margin: 1,
+    transition: "background-color 0.2s",
+  };
+
+  return <span data-testid={id} aria-label={state} style={style} />;
 }
diff --git a/src/components/LampLine.tsx b/src/components/LampLine.tsx
index 92432d6..41ac281 100644
--- a/src/components/LampLine.tsx
+++ b/src/components/LampLine.tsx
@@ -1,5 +1,5 @@
-import { LampState } from '../types';
-import { Lamp } from './Lamp';
+import { LampState } from "../types";
+import { Lamp } from "./Lamp";
 
 interface LampLineProps {
   states: LampState[];
@@ -7,11 +7,32 @@ interface LampLineProps {
 }
 
 export function LampLine({ states, rowTestId }: LampLineProps) {
+  const len = states.length;
   return (
-    <div data-testid={rowTestId ?? "lamp-line"}>
-      {states.map((state, index) => (
-        <Lamp key={index} state={state} id={`lamp-${index}`} />
-      ))}
+    <div
+      data-testid={rowTestId ?? "lamp-line"}
+      style={{ display: "flex", gap: 2, marginBottom: 5 }}
+    >
+      {states.map((state, index) => {
+        let variant: "alone" | "first" | "last" | "middle" | undefined;
+        if (len === 1) {
+          variant = "alone";
+        } else if (index === 0) {
+          variant = "first";
+        } else if (index === len - 1) {
+          variant = "last";
+        } else {
+          variant = "middle";
+        }
+        return (
+          <Lamp
+            key={index}
+            state={state}
+            id={`lamp-${index}`}
+            variant={variant}
+          />
+        );
+      })}
     </div>
   );
 }
diff --git a/src/containers/BerlinClock.tsx b/src/containers/BerlinClock.tsx
index 31fb3dc..718063f 100644
--- a/src/containers/BerlinClock.tsx
+++ b/src/containers/BerlinClock.tsx
@@ -12,8 +12,11 @@ export function BerlinClock({ enabled, clock }: BerlinClockProps) {
 
   return (
     <div>
-      <div data-testid="seconds-row">
-        <Lamp state={clock.secondsRow[0]} id="seconds-lamp" />
+      <div
+        data-testid="seconds-row"
+        style={{ display: "flex", gap: 2, marginBottom: 5 }}
+      >
+        <Lamp state={clock.secondsRow[0]} id="seconds-lamp" variant="alone" />
       </div>
       <LampLine states={clock.fiveHours} rowTestId="five-hours-row" />
       <LampLine states={clock.oneHour} rowTestId="single-hours-row" />
diff --git a/src/containers/DigitalClock.tsx b/src/containers/DigitalClock.tsx
index c97c4d0..a2c7678 100644
--- a/src/containers/DigitalClock.tsx
+++ b/src/containers/DigitalClock.tsx
@@ -1,5 +1,5 @@
-import { useState } from 'react';
-import { dateToDigital, digitalToDate } from '../utils';
+import { useState } from "react";
+import { dateToDigital, digitalToDate } from "../utils";
 
 interface DigitalClockProps {
   enabled: boolean;
@@ -7,7 +7,11 @@ interface DigitalClockProps {
   onTimeChange: (time: Date) => void;
 }
 
-export function DigitalClock({ enabled, currentTime, onTimeChange }: DigitalClockProps) {
+export function DigitalClock({
+  enabled,
+  currentTime,
+  onTimeChange,
+}: DigitalClockProps) {
   const [inputValue, setInputValue] = useState(dateToDigital(currentTime));
 
   const handleChange = (e: React.ChangeEvent<HTMLInputElement>) => {
diff --git a/src/hooks/useCurrentTime.ts b/src/hooks/useCurrentTime.ts
index da9055d..adc7c3f 100644
--- a/src/hooks/useCurrentTime.ts
+++ b/src/hooks/useCurrentTime.ts
@@ -1,4 +1,4 @@
-import { useState } from 'react';
+import { useState } from "react";
 
 export function useCurrentTime(): {
   currentTime: Date;
diff --git a/src/setupTests.ts b/src/setupTests.ts
index 7b0828b..d0de870 100644
--- a/src/setupTests.ts
+++ b/src/setupTests.ts
@@ -1 +1 @@
-import '@testing-library/jest-dom';
+import "@testing-library/jest-dom";
diff --git a/src/types/index.ts b/src/types/index.ts
index 8ec6dc0..20f7489 100644
--- a/src/types/index.ts
+++ b/src/types/index.ts
@@ -1,8 +1,8 @@
 export enum LampState {
-  Y = 'Y',   // Yellow
-  R = 'R',   // Red
-  O = 'O',   // Off
-  N = 'N',   // None / undefined
+  Y = "Y", // Yellow
+  R = "R", // Red
+  O = "O", // Off
+  N = "N", // None / undefined
 }
 
 export interface BerlinClock {
diff --git a/src/utils/index.ts b/src/utils/index.ts
index f497273..71a8069 100644
--- a/src/utils/index.ts
+++ b/src/utils/index.ts
@@ -1,13 +1,13 @@
-import type { BerlinClock } from '../types';
-import { LampState } from '../types';
+import type { BerlinClock } from "../types";
+import { LampState } from "../types";
 
 export function dateToDigital(date: Date): string {
-  const pad = (n: number) => n.toString().padStart(2, '0');
+  const pad = (n: number) => n.toString().padStart(2, "0");
   return `${pad(date.getHours())}:${pad(date.getMinutes())}:${pad(date.getSeconds())}`;
 }
 
 export function digitalToDate(digital: string): Date {
-  const parts = digital.split(':');
+  const parts = digital.split(":");
   if (parts.length !== 3) return new Date(NaN);
   const [h, m, s] = parts.map(Number);
   if (isNaN(h) || isNaN(m) || isNaN(s)) return new Date(NaN);
@@ -65,8 +65,7 @@ export function berlinToDate(berlin: BerlinClock): Date {
     arr.filter((s) => s === LampState.R || s === LampState.Y).length;
 
   const hours = countR(berlin.fiveHours) * 5 + countR(berlin.oneHour);
-  const minutes =
-    countYorR(berlin.fiveMinutes) * 5 + countY(berlin.oneMinute);
+  const minutes = countYorR(berlin.fiveMinutes) * 5 + countY(berlin.oneMinute);
 
   const d = new Date();
   d.setHours(hours, minutes, 0, 0);