Purposes CSS files in Liferay theme

Default theme CSS files and their purposes.

File	Purpose
application.css	Contains default styling having to do with components of applications. This includes the tabs, expandable trees, dialog overlays, and the results grid (that is, search container). Much of the markup for these styles is created by Liferay’s tag libraries.
base.css	Contains default styling for standard HTML tags, such as paragraphs, headings,tables, and more. This file also contains styling for some Liferay-specific page elements, such as errors, warnings, tooltips, the loading animation, and more.
dockbar.css	Contains default styling for the Dockbar, which floats at the top of the page when a user is logged in
custom.css	A blank file that is loaded last. As a best practice, theme developers should put their custom styles here to override default styles provided by Liferay in the other theme CSS files.
forms.css	Contains default styling for all form elements.
layout.css	Contains default styling used by layout templates.
main.css	Contains no styling, but imports the rest of the files.
navigation.css	Contains default styling for the main navigation elements.
portlet.css	Contains default styling for the portlet windows.

Purposes of Vm files in Liferay theme

Default theme velocity files and their purposes.

File	Purpose
init_custom.vm	Allows you to add custom Velocity variables.
init.vm	In conjunction with VelocityVariables.java in Liferay, sets many Velocity variables that correspond to Liferay Java objects.
navigation.vm	Implements the page navigation within the theme.
portal_normal.vm	The overall template for all pages the theme implements. This file includes the other files.
portal_pop_up.vm	The overall template for any portlets that use the Liferay pop-up custom window state.
portlet.vm	The template for portlet windows within the theme.