An alternative to select elements as navigation in narrow viewports is from 456 Berea Street.
The W3C published a recommendation document on media queries yesterday.
An Introduction to WebVTT and <track> is at Opera Dev. “Web Video Text Tracks, more commonly known as WebVTT, is a file format that allows us to mark up external text tracks. Using it in conjunction with HTML5‘s <track> element means we can associate information such as subtitles, captions and descriptions for a media resource such as audio or video, and display them synchronised with the media resource.”