CiviCRM's current default UI, 'Greenwich' has been running since Civi 3.x, around 2009. This Milestone is to group the various issues and steps towards improving how CiviCRM looks out of the box, including accessibility. Includes possibly a new UI theme with CiviCRM that works on all Civi CMSs, is user-customisable via CSS Variables, and meets current accessibility standards.