root = Card([header, sentence, form])
header = CardHeader("The Product Weekly", "A newsletter for curious product people")
sentence = TextContent("Every Tuesday, get one tactical product insight, a reusable template, and the five best articles we found — in a five-minute read.")
form = Form("weekly-signup", formButtons, [emailField])
emailField = FormControl("Email address", emailInput, "No spam. Unsubscribe in one click anytime.")
emailInput = Input("email", "you@company.com", "email")
formButtons = Buttons([subscribeBtn])
subscribeBtn = Button("Subscribe free")