* use svg for checkbox
* update borders
* switch to rems
* define a rem function
* fix ie11 issue
* fix focus
* add ie hack
* fix spacing and switch to em
* switch to rem
* Update base/components classnames
* Fix class name conflict
* Fix some class names mismatch
* Fix review loading placeholder styles
* Fix docs format
* Update old class name
* Fix price slider regression
* Fix load more button component missing legacy class
* Fix wrong loading mask styles classname
* Remove 'checkout' from 'wc-block-components-checkout-payment-methods__save-card-info' classname
* Make it explicit legacy classes will be removed in the next major version
* Make product variation data styles belong to product metadata
* Improve docs sentence