Bijay Yadav

Easily overwrite your theme’s CSS from customizer and preview it before saving. Customizer Custom CSS does not require any configurationn and easy to use. Now there is no need of creating child theme just to change the CSS.

Customizer Custom CSS

Add Custom CSS from customizer to your WordPress website.

Bastien Ho

NOUS Open Usefull &amp; Simple

This plugin is for you if :
<ul>
<li>You know CSS, but don’t have legitimacy to apply it</li>
<li>You manage a multisite network</li>
<li>You work with webmasters which want to customize WP but think that “CSS” means “Custom Super Style”</li>
<li>You just want to use predefined styles on your blog</li>
</ul>
This plugin works as well for standard single site or multisite network.
Checkout full examples and documentation on <a href="http://css-addons.avecnous.eu/" rel="nofollow ugc">css-addons.avecnous.eu</a>
The power user can create a set of CSS rules readable for humans with :
<ul>
<li>Slug</li>
<li>Name</li>
<li>Theme</li>
<li>Descrition</li>
<li>CSS code</li>
</ul>
It adds the list of addons in the customizer view (under appearance) and webmaster just have to check the ones they want with live preview. 
That’s it. 
For coder webmasters, a free field let them put there own CSS in a code-highlighted editor.
Predefined librairies are also available:
<ul>
<li>Bootstrap 3/4</li>
<li>GithubCSS</li>
<li>Knacss</li>
<li>MarkdownCSS</li>
<li>Normalize</li>
<li>Skeleton</li>
<li>YUI 3</li>
</ul>
<h3>Languages</h3>
<ul>
<li>en : 100%</li>
<li>fr_FR : 100%</li>
</ul>

Custom CSS Addons

Description: Lets administrator add CSS addons to any theme

Customizer Custom CSS vs Custom CSS Addons