Selective CSS Aggregation for fast D7 development performance On D6, we had the this module. Depite the module's name, it has an hidden extra feature to optimizes all CSS files except for the module or theme being actively developed. This has the benefit of performance (since all files except the actively developed file are compressed) yet allows for quick development. 

Which alternative exists for Drupal 7?
At this time, it appears this module is not needed for Drupal 7
this has been committed and fixed in D7 core.

refer to this:

IE: Stylesheets ignored after 31 link/style tags

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css aggregation of all stylesheets EXCEPT certain one. just add this to your theme's template file

drupal_add_css(drupal_get_path('theme', 'mytheme') . '/css/custom.css', array(
'group' =&gt; CSS_DEFAULT,
'preprocess' =&gt; FALSE,
'every_page' =&gt; TRUE
));