refactor: update Tailwind CSS integration and enhance chart tooltip styling

- Removed the deprecated @tailwindcss/postcss dependency and updated to use tailwindcss directly in postcss.config.js.
- Downgraded tailwindcss version to ^3.4.4 in package.json for compatibility.
- Enhanced tooltip styling in ChartContainer component with custom colors, fonts, and padding for better visual presentation.
- Updated tooltip callbacks to improve label formatting and added custom label colors.

Author: JavaZeroo