root = Card([header, description, signupForm])
header = CardHeader("Weekly Product Newsletter", "Stay updated with the latest features and insights")
description = TextContent("Subscribers get a curated digest of new product releases, feature deep-dives, and exclusive tips delivered every Tuesday.")
signupForm = Form("newsletter-signup", formButtons, [emailField])
emailField = FormControl("Email address", emailInput, "We respect your inbox. Unsubscribe anytime.")
emailInput = Input("email", "you@company.com", "email")
formButtons = Buttons([subscribeBtn])
subscribeBtn = Button("Subscribe", null, "primary")