root = Card([header, amountCard, dueDate, payActions])
header = CardHeader("Invoice #INV-2024-001", "From: Jane Design Studio · To: Acme Corp")
amountCard = Card([amountLabel, amountValue], "sunk", "column", "m", "center")
amountLabel = TextContent("Amount Due", "small-heavy")
amountValue = TextContent("$2,500.00 USD", "large-heavy")
dueDate = TextContent("Due Date: January 15, 2025", "default")
payActions = Buttons([payNowBtn], "row")
payNowBtn = Button("Pay Now", null, "primary", "normal", "large")