Jetpack updates seem to be cruising right along these days. The 1.7 release includes one of the most useful new features to date – the Custom CSS module.
This new addition allows you to override or replace your theme’s CSS in the dashboard. No child theme is required for this custom CSS file, although you will still need a child theme if you want to customize your theme’s template files.
You can configure the module by turning it on in Jetpack and then navigating to Appearance >> Edit CSS.