While we have a variety of color and other options in the admin panel, some people want to change more for their particular site.
The CSS file located in wp-content/plugins/raffle-ticket-generator-platinium/includes/css/style.css can be edited. This can be overwritten when updating plugin so make sure you keep backups of any changes.
Here are the sections that handle the pick a number displays:
.ticket-box-wrap main div