This is a beta/temporary version of Themer for the widget. It is fully functional but in future I'd like to make it (if I have enough time) more accessible for people who have difficulties with CSS.
This is a new feature and these custom themes will remain even after the plugin update.
You can use the editor below or your favorite IDE (LESS is easier) and then copy/paste your CSS in the editor. (this editor do not convert LESS to CSS)
Please note that you have to add the calss "arw-theme1" to the .calendar-archives fro the Theme 1 ans "arw-theme2" for the Theme 2. Without it the theme will be applied to all widgets on the page. (e.g.: .calendar-archives.arw-theme1{} )