In reply to Rahul Ramesh.

H2s are not suitable for subtitles. Please read the documentation for why:

* 5. The reason that are being used is because HTML does not have a dedicated mechanism for
* marking up subheadings, alternative titles, or taglines. There are suggested alternatives from
* the World Wide Web Consortium (W3C); among them are spans, which work well for what we're trying
* to do with titles in WordPress. See the linked documentation for more information.

See the W3C for more information.

If you're concerned about the markup of the output, you can also filter it to your liking.

There is only one CSS file output to the front end of the site. The other files are for the back end of your site. There's one CSS file to style the input, one JS file to manage the input interactions, and one CSS file for a sensible style default for your subtitles.

Any additional concerns you may have I'll be happy to answer on GitHub or on WordPress.org.