This plugin hasn’t been updated in over 2 years. It may no longer be maintained or supported and may have compatibility issues when used with more recent versions of WordPress.

Simpler CSS


This Simpler CSS mu-plugin allows WordPress µ hosts to enable users to add custom stylesheets to their blogs.

The plugin creates a new menu item under the Appearance menu in WordPress 2.7
that allows users to enter custom CSS code that will be injected into the
section of their blog. The CSS is stored in the blog’s options table
and is filtered through a standard PHP function before being outputted, preventing
the user from inserting malicious code into the header.

For non-WordPress µ blogs, this plugin provides an easy way to modify the appearance of installed
themes or plugins (such as Sociable) without modifying theme/plugin files that may change
with upgrades. No write access is required to any files for Simpler CSS to function, as it stores
its data in the database’s options table — and that means theme/plugin upgrades won’t impact
your custom CSS.

The custom CSS will only show when the theme has the necessary wp_header() function
in the <head> section, as most themes now do.

Props go to Jeremiah Orem who created the original Custom User CSS plugin on the directory.
I merely took that, contributed a thorough readme.txt, and fixed the code to add the menu item
under the Appearance menu.


  • The menu item as it appears under the Appearance menu.
  • The options page, with CSS code.


For WordPress µ

  1. Upload the simpler-css.php file to the /wp-content/mu-plugins/ directory. The other files
    should not be uploaded, and the file cannot be in a subdirectory.
  2. You’re done! As a mu-plugin, Simpler CSS is automatically enabled for all blogs.

For normal WordPress installations

  1. Upload the simpler-css directory to the /wp-content/plugins/ directory.
  2. Activate the plugin through the ‘Plugins’ menu in WordPress.


Why isn’t the code showing up on the blog?

Remember that this plugin depends on standard WordPress hooks to operate. If the
active theme does not have wp_header() in its code, this plugin is ineffective.
Remedy: add the code <?php wp_header(); ?> to the theme files in the <head> section.

Why can’t I add JavaScript to the blog’s code?

This plugin will only operate for Cascading Style Sheets code. The custom CSS is escaped
and outputted within a set of <style> tags, preventing bots from abusing the functionality
to inject malicious code. Allowing users to inject JavaScript into the blog’s header
is a security vulnerability, thus this plugin does not permit it.

Why isn’t my CSS showing as it should be?

Check first of all to make sure that your custom CSS does not include the opening <style type="text/css">
and closing </style> HTML tags. These tags are outputted automatically, and including
them manually in your CSS code could lead to malfunctions.

Contributors & Developers

“Simpler CSS” is open source software. The following people have contributed to this plugin.


Translate “Simpler CSS” into your language.

Interested in development?

Browse the code, check out the SVN repository, or subscribe to the development log by RSS.



  • Updated compatibility to 3.0-alpha (Subversion trunk version)
  • Fixed htmlspecialchars() usage to be compatible with PHP < 5.2.3


  • Fixed <td> tag that wasn’t closed
  • Changed regular expression pattern to be more liberal, to allow external URLs


  • Updated compatibility to 2.9-rare (Subversion trunk version)