John Regan

Add Custom CSS to your WordPress site without any hassles.
An easy-to-use WordPress Plugin to add custom CSS styles that override Plugin and Theme default styles. This plugin is designed to meet the needs of administrators who would like to add their own CSS to their WordPress website. Styles created with this plugin will render even if the theme is changed.
New in Version 4.0.7
<ul>
<li>Tested for compatibility with WP 6.7.2</li>
<li>Tested for compatibility with PHP 8.4</li>
</ul>
<h3>Features</h3>
<ul>
<li>AMP Support</li>
<li>Customizer Control (live preview)</li>
<li>Useful Code Syntax Highlighter</li>
<li>Code linting (error checking)</li>
<li>No configuration needed</li>
<li>Simple interface built on native WordPress UI</li>
<li>Virtually no impact on site performance</li>
<li>No complicated database queries</li>
<li>Thorough documentation</li>
<li>Allows Administrator access on WP Networks (Multisite)</li>
</ul>
<h3>Usage</h3>
<ol>
<li>
Navigate to Appearance > Custom CSS in the Admin Menu
</li>
<li>
Enter in valid CSS styles
</li>
<li>
Click “Update Custom CSS”
</li>
<li>
View your changes in the Front End of your website
</li>
</ol>
<h3>Help</h3>
<a href="https://github.com/johnregan3/simple-custom-css/wiki" title="Simple Custom CSS Wiki" rel="nofollow ugc">Simple Custom CSS Wiki</a>
<a href="https://wordpress.org/support/plugin/simple-custom-css" title="Support Forum" rel="ugc">Support Forum</a>

Simple Custom CSS Plugin

This is one of the best Custom CSS Plugin I've ever used. I've been using it since 2016. This plugin works very well.

Simple but works really good.

Add Custom CSS to your WordPress site without any hassles.

John Cummings

If you’ve ever wanted to control how a particular part of your page or posts looks without having to modify the theme files or stylesheets, 
this is a simple plugin that allows you to do that.
Once installed and activated, you’ll have a new settings panel in the WordPress admin that will provide you with a text area block 
where you can include any styling you’d like to use, and a second input field that allows you to insert a comma delimited list of page 
or post IDs to apply these styles to.
Alternatively, you can enter ‘ALL’, and have your styles applied on every page/post.
Bug Reports or Feature Requests 
https://trello.com/b/9Bio6kHl
Follow me on Twitter 
https://twitter.com/jcummings1974

CSS Theme Override

Adds a settings panel to the Wordpress admin that allows you to specify css class or id styles and pages/posts to apply them to.

Simple Custom CSS Plugin vs CSS Theme Override