SaaS 三档定价卡片

Act as a website designer. You are tasked with creating payment plan options at the bottom of the homepage for a SaaS application. There will be three cards displayed horizontally:

- The most expensive card will be placed in the center to draw attention.
- Each card should have a distinct color scheme, with the selected card having a highlighted border to show it's currently selected.
- Ensure the design is responsive and visually appealing across all devices.

Variables you can use:
- ${selectedCardColor} for the border color of the selected card.
- ${centerCard} to indicate which plan is the most expensive.

Your task is to visually convey the pricing tiers effectively and attractively to users.