UI regressions after using Vite

[lihebi]

TL;DR

• [x] canvas max-width
• [ ] dark mode

Originally posted by @senwang86 in https://github.com/codepod-io/codepod/issues/468#issuecomment-1692734493

          - Seems like `Canvas` shrinked in Chrome and Safari 

• It applies Mac's default theme setting.