George Stephanis

This plugin re-adds a standalone editing page for Custom CSS 
in the WordPress Admin UI, for users that aren’t comfortable 
using the one in the Customizer.
Currently it only works with Jetpack and Jetpack’s added features, 
but shortly it will work without Jetpack as well, providing a 
more basic text editor without syntax highlighting.

Legacy Jetpack Custom CSS Editor

I was utterly dismayed to see the old Jetpack CSS editor disappear in favor of a little customizer box in WP 4.7. Thank you so much for restoring the legacy editor where we can actually see what we're working with, and where our designer can work with CSS without having to upload style.css every time they make a change. It's a vital part of our workflow and the little box in the customizer is completely inadequate.

many thanks for this lifesaver

This plugin re-adds the full page admin Custom CSS editor to Jetpack.

FRESHFACE

Create custom CSS and JS codes. Delivered with our awesome Conditional Logic, you can easily specify 
where you want to your custom CSS code appear. You can write your CSS and JS codes inside 
nice ACE editor with syntax highlighter.Codes will be still presented, after you change the theme, 
so this is really good way to write CSS adjustments into your theme.

Custom CSS

Although this plugin does what it's supposed to I don't want to keep clicking the "buy pro version" button because it is the same color and exactly below the standard WordPress update button in the Publish metabox.  Putting it in that spot with that color is deceptive, if your plugin is good and useful people will upgrade to pro naturally, you don't need to trick anyone into clicking - this isn't SEO!

Pro version promotion over the top

Worthless. Just trys to force you to buy the 100 version

Worthless as a free app

No way to add ANY custom code, but there is a huge "upgrade to premium" button.

Add custom CSS, JS, PHP, tracking code. Very easy to use!

Legacy Jetpack Custom CSS Editor vs Custom CSS