Update on 25 Oct 2021: The tutorial below has not been tested with the recent versions of Oxygen. You might want to try the newer methods shared in GitHub here instead.
Update on December 12, 2019: Use this plugin to fix the duplicate IDs problem in Oxygen’s Repeater components’ output.
Add a class to elements of your Repeater and style the classes.
Add a Code Block.
PHP & HTML:
<?php // echo "hello world!"; ?>