diff --git a/userfront-e2e/pnpm-lock.yaml b/userfront-e2e/pnpm-lock.yaml
new file mode 100644
index 00000000..198583a6
--- /dev/null
+++ b/userfront-e2e/pnpm-lock.yaml
@@ -0,0 +1,77 @@
+lockfileVersion: '9.0'
+
+settings:
+  autoInstallPeers: true
+  excludeLinksFromLockfile: false
+
+importers:
+
+  .:
+    devDependencies:
+      '@playwright/test':
+        specifier: ^1.58.2
+        version: 1.60.0
+      '@types/node':
+        specifier: ^24.3.0
+        version: 24.12.4
+      typescript:
+        specifier: ^5.9.2
+        version: 5.9.3
+
+packages:
+
+  '@playwright/test@1.60.0':
+    resolution: {integrity: sha512-O71yZIbAh/PxDMNGns37GHBIfrVkEVyn+AXyIa5dOTfb4/xNvRWV+Vv/NMbNCtODB/pO7vLlF2OTmMVLhmr7Ag==}
+    engines: {node: '>=18'}
+    hasBin: true
+
+  '@types/node@24.12.4':
+    resolution: {integrity: sha512-GUUEShf+PBCGW2KaXwcIt3Yk+e3pkKwWKb9GSyM9WQVE+ep2jzmHdGsHzu4wgcZy5fN9FBdVzjpBQsYlpfpgLA==}
+
+  fsevents@2.3.2:
+    resolution: {integrity: sha512-xiqMQR4xAeHTuB9uWm+fFRcIOgKBMiOBP+eXiyT7jsgVCq1bkVygt00oASowB7EdtpOHaaPgKt812P9ab+DDKA==}
+    engines: {node: ^8.16.0 || ^10.6.0 || >=11.0.0}
+    os: [darwin]
+
+  playwright-core@1.60.0:
+    resolution: {integrity: sha512-9bW6zvX/m0lEbgTKJ6YppOKx8H3VOPBMOCFh2irXFOT4BbHgrx5hPjwJYLT40Lu+4qtD36qKc/Hn56StUW57IA==}
+    engines: {node: '>=18'}
+    hasBin: true
+
+  playwright@1.60.0:
+    resolution: {integrity: sha512-hheHdokM8cdqCb0lcE3s+zT4t4W+vvjpGxsZlDnikarzx8tSzMebh3UiFtgqwFwnTnjYQcsyMF8ei2mCO/tpeA==}
+    engines: {node: '>=18'}
+    hasBin: true
+
+  typescript@5.9.3:
+    resolution: {integrity: sha512-jl1vZzPDinLr9eUt3J/t7V6FgNEw9QjvBPdysz9KfQDD41fQrC2Y4vKQdiaUpFT4bXlb1RHhLpp8wtm6M5TgSw==}
+    engines: {node: '>=14.17'}
+    hasBin: true
+
+  undici-types@7.16.0:
+    resolution: {integrity: sha512-Zz+aZWSj8LE6zoxD+xrjh4VfkIG8Ya6LvYkZqtUQGJPZjYl53ypCaUwWqo7eI0x66KBGeRo+mlBEkMSeSZ38Nw==}
+
+snapshots:
+
+  '@playwright/test@1.60.0':
+    dependencies:
+      playwright: 1.60.0
+
+  '@types/node@24.12.4':
+    dependencies:
+      undici-types: 7.16.0
+
+  fsevents@2.3.2:
+    optional: true
+
+  playwright-core@1.60.0: {}
+
+  playwright@1.60.0:
+    dependencies:
+      playwright-core: 1.60.0
+    optionalDependencies:
+      fsevents: 2.3.2
+
+  typescript@5.9.3: {}
+
+  undici-types@7.16.0: {}
diff --git a/userfront-e2e/tests/signup-theme-visibility.spec.ts b/userfront-e2e/tests/signup-theme-visibility.spec.ts
new file mode 100644
index 00000000..6acb3a83
--- /dev/null
+++ b/userfront-e2e/tests/signup-theme-visibility.spec.ts
@@ -0,0 +1,465 @@
+import { expect, test, type Locator, type Page, type Route } from '@playwright/test';
+import { inflateSync } from 'node:zlib';
+
+type ThemeCase = {
+  name: 'light' | 'dark';
+};
+
+const themeCases: ThemeCase[] = [
+  { name: 'light' },
+  { name: 'dark' },
+];
+
+type Rgb = {
+  r: number;
+  g: number;
+  b: number;
+};
+
+async function mockSignupApis(page: Page): Promise<void> {
+  await page.route('**/api/v1/**', async (route: Route) => {
+    const request = route.request();
+    const requestUrl = new URL(request.url());
+    const path = requestUrl.pathname;
+    const method = request.method().toUpperCase();
+
+    if (path.endsWith('/api/v1/user/me')) {
+      await route.fulfill({
+        status: 401,
+        contentType: 'application/json',
+        body: JSON.stringify({ error: 'unauthorized' }),
+      });
+      return;
+    }
+
+    if (path.endsWith('/api/v1/auth/password/policy')) {
+      await route.fulfill({
+        status: 200,
+        contentType: 'application/json',
+        body: JSON.stringify({
+          minLength: 12,
+          minCharacterTypes: 3,
+          lowercase: true,
+          uppercase: true,
+          number: true,
+          nonAlphanumeric: true,
+        }),
+      });
+      return;
+    }
+
+    if (path.endsWith('/api/v1/auth/signup/check-email') && method === 'POST') {
+      await route.fulfill({
+        status: 200,
+        contentType: 'application/json',
+        body: JSON.stringify({ available: true }),
+      });
+      return;
+    }
+
+    if (
+      (path.endsWith('/api/v1/auth/signup/send-email-code') ||
+        path.endsWith('/api/v1/auth/signup/send-sms-code')) &&
+      method === 'POST'
+    ) {
+      await route.fulfill({
+        status: 200,
+        contentType: 'application/json',
+        body: JSON.stringify({ ok: true }),
+      });
+      return;
+    }
+
+    if (path.endsWith('/api/v1/auth/signup/verify-code') && method === 'POST') {
+      await route.fulfill({
+        status: 200,
+        contentType: 'application/json',
+        body: JSON.stringify({ success: true, isAffiliate: false }),
+      });
+      return;
+    }
+
+    if (path.endsWith('/api/v1/auth/signup') && method === 'POST') {
+      await route.fulfill({
+        status: 200,
+        contentType: 'application/json',
+        body: JSON.stringify({ ok: true }),
+      });
+      return;
+    }
+
+    if (path.endsWith('/api/v1/auth/tenant-info')) {
+      await route.fulfill({
+        status: 200,
+        contentType: 'application/json',
+        body: JSON.stringify({}),
+      });
+      return;
+    }
+
+    if (path.endsWith('/api/v1/client-log')) {
+      await route.fulfill({
+        status: 200,
+        contentType: 'application/json',
+        body: JSON.stringify({ ok: true }),
+      });
+      return;
+    }
+
+    await route.fulfill({
+      status: 200,
+      contentType: 'application/json',
+      body: JSON.stringify({}),
+    });
+  });
+}
+
+async function enableFlutterAccessibility(page: Page): Promise<void> {
+  const button = page.getByRole('button', { name: 'Enable accessibility' });
+  if (await button.count()) {
+    await button.first().click({ force: true }).catch(async () => {
+      await page.locator('flt-semantics-placeholder').first().evaluate((node) => {
+        (node as HTMLElement).click();
+      });
+    });
+    await page.waitForTimeout(400);
+  }
+}
+
+async function typeIntoField(page: Page, locator: Locator, value: string): Promise<void> {
+  await locator.scrollIntoViewIfNeeded();
+  await page.waitForTimeout(100);
+  await locator.evaluate((node, nextValue) => {
+    if (
+      node instanceof HTMLInputElement ||
+      node instanceof HTMLTextAreaElement
+    ) {
+      node.focus();
+      node.value = '';
+      node.dispatchEvent(new Event('input', { bubbles: true }));
+      node.value = nextValue;
+      node.dispatchEvent(new Event('input', { bubbles: true }));
+      node.dispatchEvent(new Event('change', { bubbles: true }));
+    }
+  }, value).catch(() => {});
+  const box = await locator.boundingBox();
+  if (!box) {
+    throw new Error('Field locator is not visible for typing.');
+  }
+  await page.locator('flt-glass-pane').click({
+    position: {
+      x: box.x + box.width / 2,
+      y: box.y + box.height / 2,
+    },
+    force: true,
+  });
+  await page.waitForTimeout(100);
+  await page.keyboard.press('Control+A');
+  await page.keyboard.press('Backspace');
+  await page.keyboard.type(value);
+  await page.waitForTimeout(150);
+}
+
+async function sampleViewportColor(
+  page: Page,
+  x: number,
+  y: number,
+  radius = 2,
+): Promise<Rgb> {
+  const buffer = await page.screenshot();
+  const image = decodePng(buffer);
+  const clampedX = Math.max(0, Math.min(image.width - 1, Math.round(x)));
+  const clampedY = Math.max(0, Math.min(image.height - 1, Math.round(y)));
+  return sampleAverageColor(image, clampedX, clampedY, radius);
+}
+
+function decodePng(buffer: Buffer): {
+  width: number;
+  height: number;
+  pixels: Uint8Array;
+} {
+  const signature = buffer.subarray(0, 8).toString('hex');
+  if (signature !== '89504e470d0a1a0a') {
+    throw new Error('Invalid PNG signature');
+  }
+
+  let offset = 8;
+  let width = 0;
+  let height = 0;
+  let colorType = 0;
+  const idatChunks: Buffer[] = [];
+
+  while (offset < buffer.length) {
+    const length = buffer.readUInt32BE(offset);
+    const type = buffer.subarray(offset + 4, offset + 8).toString('ascii');
+    const data = buffer.subarray(offset + 8, offset + 8 + length);
+    offset += 12 + length;
+
+    if (type === 'IHDR') {
+      width = data.readUInt32BE(0);
+      height = data.readUInt32BE(4);
+      colorType = data[9];
+    } else if (type === 'IDAT') {
+      idatChunks.push(data);
+    } else if (type === 'IEND') {
+      break;
+    }
+  }
+
+  if (!width || !height || ![2, 6].includes(colorType)) {
+    throw new Error(`Unsupported PNG format: ${width}x${height}, color=${colorType}`);
+  }
+
+  const bytesPerPixel = colorType === 6 ? 4 : 3;
+  const stride = width * bytesPerPixel;
+  const inflated = inflateSync(Buffer.concat(idatChunks));
+  const raw = new Uint8Array(height * stride);
+
+  let sourceOffset = 0;
+  let targetOffset = 0;
+
+  for (let y = 0; y < height; y += 1) {
+    const filter = inflated[sourceOffset];
+    sourceOffset += 1;
+    for (let x = 0; x < stride; x += 1) {
+      const value = inflated[sourceOffset + x];
+      const left = x >= bytesPerPixel ? raw[targetOffset + x - bytesPerPixel] : 0;
+      const up = y > 0 ? raw[targetOffset + x - stride] : 0;
+      const upLeft =
+        y > 0 && x >= bytesPerPixel
+          ? raw[targetOffset + x - stride - bytesPerPixel]
+          : 0;
+      raw[targetOffset + x] = unfilterByte(filter, value, left, up, upLeft);
+    }
+    sourceOffset += stride;
+    targetOffset += stride;
+  }
+
+  const pixels = new Uint8Array(width * height * 4);
+  for (let i = 0, j = 0; i < raw.length; i += bytesPerPixel, j += 4) {
+    pixels[j] = raw[i];
+    pixels[j + 1] = raw[i + 1];
+    pixels[j + 2] = raw[i + 2];
+    pixels[j + 3] = colorType === 6 ? raw[i + 3] : 255;
+  }
+
+  return { width, height, pixels };
+}
+
+function unfilterByte(
+  filter: number,
+  value: number,
+  left: number,
+  up: number,
+  upLeft: number,
+): number {
+  if (filter === 0) {
+    return value;
+  }
+  if (filter === 1) {
+    return (value + left) & 0xff;
+  }
+  if (filter === 2) {
+    return (value + up) & 0xff;
+  }
+  if (filter === 3) {
+    return (value + Math.floor((left + up) / 2)) & 0xff;
+  }
+  if (filter === 4) {
+    return (value + paeth(left, up, upLeft)) & 0xff;
+  }
+  throw new Error(`Unsupported PNG filter: ${filter}`);
+}
+
+function paeth(left: number, up: number, upLeft: number): number {
+  const estimate = left + up - upLeft;
+  const leftDistance = Math.abs(estimate - left);
+  const upDistance = Math.abs(estimate - up);
+  const upLeftDistance = Math.abs(estimate - upLeft);
+  if (leftDistance <= upDistance && leftDistance <= upLeftDistance) {
+    return left;
+  }
+  if (upDistance <= upLeftDistance) {
+    return up;
+  }
+  return upLeft;
+}
+
+function sampleAverageColor(
+  image: { width: number; height: number; pixels: Uint8Array },
+  x: number,
+  y: number,
+  radius = 2,
+): Rgb {
+  const xStart = Math.max(0, Math.min(image.width - 1, x - radius));
+  const xEnd = Math.max(0, Math.min(image.width - 1, x + radius));
+  const yStart = Math.max(0, Math.min(image.height - 1, y - radius));
+  const yEnd = Math.max(0, Math.min(image.height - 1, y + radius));
+
+  let totalR = 0;
+  let totalG = 0;
+  let totalB = 0;
+  let count = 0;
+
+  for (let sampleY = yStart; sampleY <= yEnd; sampleY += 1) {
+    for (let sampleX = xStart; sampleX <= xEnd; sampleX += 1) {
+      const offset = (sampleY * image.width + sampleX) * 4;
+      const alpha = image.pixels[offset + 3];
+      if (alpha < 16) {
+        continue;
+      }
+      totalR += image.pixels[offset];
+      totalG += image.pixels[offset + 1];
+      totalB += image.pixels[offset + 2];
+      count += 1;
+    }
+  }
+
+  if (count === 0) {
+    throw new Error(`No visible pixels in sampled region at ${x}, ${y}`);
+  }
+
+  return {
+    r: Math.round(totalR / count),
+    g: Math.round(totalG / count),
+    b: Math.round(totalB / count),
+  };
+}
+
+function brightness(rgb: Rgb): number {
+  return (rgb.r + rgb.g + rgb.b) / 3;
+}
+
+async function sampleLocatorColor(page: Page, locator: Locator, radius = 2): Promise<Rgb> {
+  const box = await locator.boundingBox();
+  if (!box) {
+    throw new Error('Target locator is not visible for color sampling.');
+  }
+  return sampleViewportColor(page, box.x + box.width / 2, box.y + box.height / 2, radius);
+}
+
+async function sampleCheckboxColor(page: Page, locator: Locator): Promise<Rgb> {
+  const box = await locator.boundingBox();
+  if (!box) {
+    throw new Error('Checkbox locator is not visible for color sampling.');
+  }
+  const x = box.x + Math.min(18, Math.max(12, box.width * 0.08));
+  const y = box.y + box.height / 2;
+  return sampleViewportColor(page, x, y, 0);
+}
+
+async function sampleButtonColor(page: Page, locator: Locator): Promise<Rgb> {
+  const box = await locator.boundingBox();
+  if (!box) {
+    throw new Error('Button locator is not visible for color sampling.');
+  }
+  const x = box.x + box.width * 0.2;
+  const y = box.y + box.height / 2;
+  return sampleViewportColor(page, x, y, 1);
+}
+
+async function sampleButtonBackground(page: Page, locator: Locator): Promise<Rgb> {
+  const box = await locator.boundingBox();
+  if (!box) {
+    throw new Error('Button locator is not visible for background sampling.');
+  }
+  const x = box.x + box.width / 2;
+  const y = Math.max(0, box.y - 14);
+  return sampleViewportColor(page, x, y, 2);
+}
+
+async function expectBrightnessContrast(
+  sample: () => Promise<{ foreground: Rgb; background: Rgb }>,
+  minimumDelta: number,
+): Promise<void> {
+  await expect
+    .poll(async () => {
+      const { foreground, background } = await sample();
+      return Math.abs(brightness(foreground) - brightness(background));
+    }, { timeout: 10_000 })
+    .toBeGreaterThanOrEqual(minimumDelta);
+}
+
+async function expectButtonContrast(page: Page, locator: Locator): Promise<void> {
+  await expectBrightnessContrast(async () => {
+    return {
+      foreground: await sampleButtonColor(page, locator),
+      background: await sampleButtonBackground(page, locator),
+    };
+  }, 45);
+}
+
+async function sampleCheckboxBackground(page: Page, locator: Locator): Promise<Rgb> {
+  const box = await locator.boundingBox();
+  if (!box) {
+    throw new Error('Checkbox locator is not visible for background sampling.');
+  }
+  const x = box.x + Math.min(42, Math.max(30, box.width * 0.18));
+  const y = box.y + box.height / 2;
+  return sampleViewportColor(page, x, y, 1);
+}
+
+async function expectCheckboxContrast(page: Page, locator: Locator): Promise<void> {
+  await expectBrightnessContrast(async () => {
+    return {
+      foreground: await sampleCheckboxColor(page, locator),
+      background: await sampleCheckboxBackground(page, locator),
+    };
+  }, 40);
+}
+
+test.describe('UserFront signup theme visibility', () => {
+  for (const theme of themeCases) {
+    test(`signup keeps ${theme.name} theme colors visible across steps`, async ({
+      page,
+    }) => {
+      await mockSignupApis(page);
+
+      if (theme.name === 'dark') {
+        await page.goto('/ko/signin', { waitUntil: 'domcontentloaded' });
+        await page.waitForTimeout(1200);
+        await enableFlutterAccessibility(page);
+        const themeToggle = page.getByRole('button', {
+          name: /Light|Dark|테마 전환|Theme toggle/i,
+        });
+        await themeToggle.click({ force: true });
+        await page.waitForTimeout(500);
+      }
+
+      await page.goto('/ko/signup', { waitUntil: 'domcontentloaded' });
+      await page.waitForTimeout(1200);
+      await enableFlutterAccessibility(page);
+
+      const allAgreementCheckbox = page.getByRole('checkbox', {
+        name: /모두 동의합니다|Agree to all/i,
+      });
+      await expect(allAgreementCheckbox).toBeVisible();
+      await allAgreementCheckbox.check({ force: true });
+
+      const nextButton = page.getByRole('button', { name: /다음 단계|Next/i });
+      await expect(nextButton).toBeVisible();
+      await expect(nextButton).toBeEnabled();
+      await nextButton.click({ force: true });
+
+      await expect(
+        page.getByText(/본인 확인을 위해|Verify your email and phone number/i),
+      ).toBeVisible();
+
+      const emailInput = page.getByRole('textbox', {
+        name: /이메일 주소|Email address/i,
+      });
+      const phoneInput = page.getByRole('textbox', {
+        name: /휴대폰 번호|Phone number/i,
+      });
+      const requestButtons = page
+        .getByRole('button')
+        .filter({ hasText: /인증요청|재발송|Send code|Resend/i });
+
+      await expect(emailInput).toBeVisible();
+      await expect(phoneInput).toBeVisible();
+      await expect(requestButtons.nth(0)).toBeVisible();
+      await expect(requestButtons.nth(1)).toBeVisible();
+      await expect(nextButton).toBeVisible();
+    });
+  }
+});