How to apply css to all pages in custom module I have created one custom module in drupal-7. I want to apply same css to all pages belonging to that module.

I am able to apply css to one page by using drupal_add_css() but not able to do for all pages.
In module's info file, add following line:

stylesheets[all][] = folder/module.css


Substitute folder with a name of subfolder within your module you keep your CSS files in (or remove it). Repeat for all CSS files you need.

More about info files in the manual on Drupal.org.