Build a plan-change screen with Tailwind CSS: current plan and target plan side by side, and a proration breakdown showing the unused credit on the old plan, the remaining cost of the new one, and the exact amount charged today. Confirm with a primary 'Switch to Pro' button, and add a downgrade variant where the charge is zero and the credit applies to the next invoice.
提示词保持英文原文——直接粘贴进 Claude、Cursor、v0 或任何 AI 编程工具即可使用。