diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
new file mode 100644
index 0000000..44decdd
--- /dev/null
+++ b/.github/workflows/lint.yml
@@ -0,0 +1,21 @@
+name: Lint
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+
+jobs:
+  python:
+    name: Python (ruff)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: astral-sh/ruff-action@v3
+
+  html:
+    name: HTML (htmlhint)
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - run: npx htmlhint "**/*.html"
diff --git a/html/radiobuttons.html b/html/radiobuttons.html
index 13ac5ad..afc4c51 100644
--- a/html/radiobuttons.html
+++ b/html/radiobuttons.html
@@ -12,52 +12,51 @@
 		<div>
 			<form action="https://buttondown.com/api/emails/embed-subscribe/{username}"
 			method="post">
-		</div>
-		<fieldset>
-			<div class="card">
-				<h3>
-					Stay informed
-				</h3>
-				<p>
-					You'll be the first to know when we launch!
-				</p>
-			</div>
-			<div>
-				<label for="email">
-					Email:
-				</label>
-				<input id="email" name="email" type="email" placeholder="m@example.com"
-				required />
-			</div>
-				<div>
-					<label for="language">
-						Language:
-					</label>
-					<input type="radio" id="english" name="english" value="english" />
-					<label for="english">
-						English
-					</label>
-					<input type="radio" id="french" name="french" value="french" />
-					<label for="french">
-						French
-					</label>
-					<input type="radio" id="spanish" name="spanish" value="spanish" />
-					<label for="spanish">
-						Spanish
-					</label>
-					<input type="radio" id="portugese" name="portugese" value="portugese"
-					/>
-					<label for="portugese">
-						Portugese
-					</label>
-				</div>
-				<div>
-					<button type="submit">
-						Subscribe
-					</button>
-				</div>
-		</fieldset>
-		</form>
+				<fieldset>
+					<div class="card">
+						<h3>
+							Stay informed
+						</h3>
+						<p>
+							You'll be the first to know when we launch!
+						</p>
+					</div>
+					<div>
+						<label for="email">
+							Email:
+						</label>
+						<input id="email" name="email" type="email" placeholder="m@example.com"
+						required />
+					</div>
+					<div>
+						<label for="language">
+							Language:
+						</label>
+						<input type="radio" id="english" name="english" value="english" />
+						<label for="english">
+							English
+						</label>
+						<input type="radio" id="french" name="french" value="french" />
+						<label for="french">
+							French
+						</label>
+						<input type="radio" id="spanish" name="spanish" value="spanish" />
+						<label for="spanish">
+							Spanish
+						</label>
+						<input type="radio" id="portugese" name="portugese" value="portugese"
+						/>
+						<label for="portugese">
+							Portugese
+						</label>
+					</div>
+					<div>
+						<button type="submit">
+							Subscribe
+						</button>
+					</div>
+				</fieldset>
+			</form>
 		</div>
 	</body>
 </html>