MD4.9.4 CSS Revamp
Part of the MD4.9.4 update is a revamp to the entire MD CSS system. Now as you enable/disable features, the main style.css file will be regenerated with only the styles needed. This will result in saving your site hundreds of lines of unused CSS which is a huge win!
6 Updates

Marketers Delight has its own built-in CSS compiler which takes cool templates like this and generates a single static file on your site.
The benefit of CSS templates is we can access dynamic color and spacing values as set from the MD Site Design options and even add and remove CSS from Dropins, child theme, and any other custom CSS with hooks and filters.

To take CSS optimization a step further, you can choose whether to print the (minified) style.css file directly to the and even combine your child theme’s styles into one main file. There is no theme as feature-rich and as optimized, and CSS features like this prove it!
Don’t take this as some flex, the benefits of the MD4.9.4 design system have huge implications on actual features on your website. The whole reason for this CSS revamp was to better integrate WooCommerce (the main feature of MD4.9.4) without killing your site’s performance.
When MD improves in one way the entire system benefits. The need to integrate WooCommerce forced me to rethink how MD integrates its own features—and the result is now a highly optimized CSS template system. The benefits of this will continue to show as new features roll out.