With the release of Panopto 5.3, Panopto allows the viewer to configure their own caption styling for session that have captions available.
When the site-wide setting is enabled, the viewer can choose their own caption preferences.
To show captions on an enabled session, select the ‘CC’ button from the bottom right corner of the Panopto player
You can now set your caption preferences
Choose whether captions are docked below the video or placed on the video
Choose whether captions are dark text on a light background, light text on a dark background, or light text with a shadow
Choose whether captions are shown using regular text or large text
To enable the setting on your site, as an administrator login and navigate to System > Settings > All Settings > UserCaptionControlsEnabled and set this to True