…to develop

YouTube source can either be on a `source` element or on the `video` element, because the cases of "local with remote sign" requires `source` but `youtube with remote sign` only requires `video`.

Fixes #674

Also switches all 'em' units to 'rem' units for consistency.

The old shadow provided player boundaries if the poster image matched the background. This is an alternate way that's less invasive.

fix for regex in the postprocessCTag function

See #680 , #675

Also: missing argument for captions button state.

See #678

…e refreshed unless the player is refreshed.

This was causing the button state to get reversed repeatedly.

See #678 (related issue.)

This worked because the selector returned an empty jQuery collection, so it was *always* running. With this change, it should only run one popups are visible.

If the 'play' event fires and 'playing' doesn't, that means that playback has failed, so there is no actual state change.

We could conceivably initiate an error state here, cleared in playing.

All this does is calculate the absdiff between these two static numbers, then never use the result.

Based on similarity, this may have been debugging related to checking whether durations are close enough.

Fixes #673

Merge Develop into Main