Different Administration Theme for Contributors?

There is this to consider Creating_Admin_Themes and the Resources of Roles and Capabilities.

Other info:
https://www.ads-software.com/extend/plugins/magic-fields/
https://www.ads-software.com/extend/plugins/ozh-admin-drop-down-menu/
https://www.ads-software.com/extend/plugins/tags/admin

Tried messing with it myself, but I am simply not experienced enough with WordPress to code it properly.

After more googling, I found this:

https://www.smashingmagazine.com/2009/12/14/advanced-power-tips-for-wordpress-template-developers-reloaded/

Specifically, the hiding fields based on user roles makes use of the following code:

//if current user level is less than 3, remove the postcustom meta box
     if ($current_user->user_level < 3)

I tried to insert it into this plugin:

<?php
/*
Plugin Name: Planet X7
Plugin URI: https://www.sevban.com/wordpress/planet-x7-wordpress-admin-theme
Description: Planet X7 theme for WordPress adminisrator area.
Author: Sevban &Otilde;zt&uuml;rk a.k.a peex
Version: 1.0.4
Author URI: https://www.sevban.com
*/

function planetx7_header() {
	$site_uri = get_settings('siteurl');
	$plugin_uri = $site_uri . '/wp-content/plugins/planet-x7/';
	echo '
	<link rel="stylesheet" type="text/css" href="' . $plugin_uri . 'planet-x7.css?version=1.0.4" />
	';
	}
	global $userdata;
     global $current_user;
require(ABSPATH . WPINC . ‘/pluggable.php’);

     get_currentuserinfo();
if ($current_user->user_level < 3)
add_action('admin_head', 'planetx7_header');

?>

and I get the error: Call to undefined function: get_currentuserinfo()

Can someone possibly insert get_currentuserinfo() into the theme plugin to call the css only when the user is a < 3 role?

Thanks in advance

Not sure about all the code in your function or outside your function there but the structure would be more like this:

add_action('admin_head', 'planetx7_header');

function planetx7_header() {
  global $current_user;
  get_currentuserinfo();
  $site_uri = get_settings('siteurl');
  $plugin_uri = $site_uri . '/wp-content/plugins/planet-x7/';
  if ($current_user->user_level < 3) {
    echo '<link rel="stylesheet" type="text/css" href="' . $plugin_uri . 'planet-x7.css?version=1.0.4" />';
  }
}

Thank you very much for you help, Micheal. I appreciate you taking the time to help me with this.

I was able to accomplish this by inserting the following code into admin-header.php

<?php
global $current_user;
	        get_currentuserinfo();
     if ($current_user->user_level < 3){
	echo '<link rel="stylesheet" type="text/css" href="experimental.css" />';
}
?>

It specifically calls the CSS when user role is < 3.