Scott Reilly

Ever want to tweak the appearance of the WordPress admin pages by hiding stuff, moving stuff around, changing fonts, colors, sizes, etc? Any modification you may want to do with CSS can easily be done via this plugin.
Using this plugin you’ll easily be able to define additional CSS (inline and/or files by URL) to be added to all administration pages. Hooks are provided to customize the output of the CSS, the CSS files, and if/when the CSS should even be output (see Hooks section).
Links: <a href="https://coffee2code.com/wp-plugins/add-admin-css/" rel="nofollow ugc">Plugin Homepage</a> | <a href="https://wordpress.org/plugins/add-admin-css/" rel="ugc">Plugin Directory Page</a> | <a href="https://github.com/coffee2code/add-admin-css/" rel="nofollow ugc">GitHub</a> | <a href="https://coffee2code.com" rel="nofollow ugc">Author Homepage</a>
<h3>Developer Documentation</h3>
Developer documentation can be found in <a href="https://github.com/coffee2code/add-admin-css/blob/master/DEVELOPER-DOCS.md" rel="nofollow ugc">DEVELOPER-DOCS.md</a>. That documentation covers the hooks provided by the plugin.
As an overview, these are the hooks provided by the plugin:
<ul>
<li><code>c2c_add_admin_css</code> : Filter to customize the CSS that should be added directly to the admin page head.</li>
<li><code>c2c_add_admin_css_files</code> : Filter to customize the list of CSS files to enqueue in the admin.</li>
<li><code>c2c_add_admin_css_disable_css</code> : Filter to customize if the CSS defined via this plugin should be output or not.</li>
</ul>

Add Admin CSS

This plugin did *exactly* what I wanted. A plugin had dropped some ad stuff into the Publish box, but it had a good CSS class, so I just hid it.

I really like that the text field for holding the CSS is intelligent and does things like auto include closing brackets, code coloring, etc.

Worked perfectly

Easily define additional CSS (inline and/or by URL) to be added to all administration pages.

jshoptaw

This plugin allows you to use uploaded CSS files that can be used across themes without having to edit any theme files or use FTP.
For example, if you wanted to use Font Awesome on your site but your current theme doesn’t include it (or you know you want to use Font Awesome regardless of what theme you’re using), you can simply upload the <code>font-awesome.css</code> (or <code>font-awesome.min.css</code>) file using the WordPress Media Uploader then activate said stylesheet in the Theme-Independent Stylesheets (TISS) settings. That CSS file will then automatically be included on your site no matter what theme you’re using. Even if you switch themes, the CSS file will still be called in your site’s <code><head></code> (as long as the theme is coded to properly use <code>wp_head()</code>, which most themes are).

Theme-Independent Stylesheets

Allows for use of uploaded stylesheets (.css files) to be used alongside any theme

Add Admin CSS vs Theme-Independent Stylesheets