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.

qstudio

Easily include browser specific stylesheets in templates or select browser and version specific classes in CSS.
Conditional browser stylesheets are added after the main theme style.css allowing them to overrule previous rules – you only need to add the CSS rules that should change.
This plugin uses up-to-date WordPress top level functions, sanitizes all input data and is fully internationalized.
For feature request and bug reports, <a href="https://qstudio.us/support/categories/conditional-stylesheets-and-body-classes" rel="nofollow ugc">please use the Q Support Website</a>.
Please do not use the WordPress.org forum to report bugs, as we no longer monitor or respond to questions there.
<h4>Features</h4>
<ul>
<li>Checks for and adds browser and version specific stylesheets – such as “browsers-windows-firefox.css”.</li>
<li>Add browser and version specific body classes to all pages – such as body.browsers-msie-10</li>
<li>Includes the Mobile Detect class and adds mobile & touch body classes.</li>
<li>Adds a post type body class, for example: “posttype-page”.</li>
<li>Inserts handy HTML comments in the HTML footer of template files to tell you which CSS files could be used and which were found.</li>
</ul>

Conditional Stylesheets and Body Classes

Add conditional browser stylesheets and body class declarations

Add Admin CSS vs Conditional Stylesheets and Body Classes