Drupal Add CSS

The Drupal Add CSS function http://api.drupal.org/api/drupal/includes%21common.inc/function/drupal_a...
has the ability to group css by weight, but it gives the appearance that you are limited to three groups.
'group': A number identifying the group in which to add the stylesheet. Available constants are:
CSS_SYSTEM: Any system-layer CSS.
CSS_DEFAULT: (default) Any module-layer CSS.
CSS_THEME: Any theme-layer CSS.

These constants are just numeric values (CSS_SYSTEM = -100, CSS_DEFAULT = 0, CSS_THEME = 100) Common Use of these looks like this

(path_to_theme() . '/css/global.css', array('group' =>CSS_THEME, 'weight' => 900'every_page' => TRUE));

Since anything with a specific group that has the "every_page =TRUE" flag gets output before items added moree selectively within the group, it makes it impossible to force your everypage css to come after that. It is not impossible, and really quite simple, just force it into a heavier group

//This forces the css into the group "200"
drupal_add_css(path_to_theme() . '/css/global.css', array('group' =>200, 'weight' => 900'every_page' => TRUE));

It is important to note, that the "weight" in the options array refers to weight WITHIN the group. While the "group" refers to the weight of the entire group. For more details of the order of processing, see the link to the Drupal documentation for drupal add css.