Magento UI library

The Magento UI library is a flexible modular Magento frontend library that is designed to assist Magento theme developers. It employs a set of mixins for base elements to ease frontend theme development and customization. The Magento UI library offers the following characteristics for those who develop or customize Magento themes. It is:

Built on LESS preprocessor
Focused on web standards
Customizable
Easy to maintain
Responsive
Accessible

The library provides the ability to customize all of the following user interface elements:

actions-toolbar
breadcrumbs
buttons
components
drop-downs
forms
icons
layout
loaders
messages
pagination
popups
ratings
resets
responsive
sections - tabs and accordions
tables
tooltips
typography
utilities
list of theme variables