fix: header and footer style

[afc163]

• [x] 修复页脚移除的问题。
• [x] 修复移动端产品卡片无法查看的问题。
• [x] 修复本地调试时 HMR 会报错的问题。

[github-actions[bot]]

🎊 PR Preview 375f10ed66a905ea874971af282bd1407cba6005 has been successfully built and deployed to https://antvis-gatsby-theme-antv-preview-pr-270.surge.sh

:clock1: Build time: 332.55s

_{🤖 By surge-preview}