CSS Audio and video

1.video: Supported formats (OGG, MP4, WEBM) most commonly used are MP4
2.audio: Supported formats (Ogg Vorbis, MP3, WAV) most commonly used are mp3
3. Both audio and video can be played via controls, AutoPlay (auto player), loop (loop).
4. Block-level:<div> belong to block-level elements
Features: Exclusive line, block-level content size, does not affect the border, the inside can nest inline elements, block-level set margins and the padding will change.
5. In-line:<span> is the inline label
Features: Can not set the width of high, the content size of the row, the impact of the border, the line inside the outer box only changes in the left and right,
6.CSS selector:
Element selector: The selected element will be selected.
Class selector: You need to name the selector with class
ID selector: You need to name the selector with an ID, but it is unique.
Descendants (derived): H1 space span
Child selector: Select only child elements as their elements
Adjacent brothers: can be immediately in another element
Wildcard: Indicates that all elements are selected

7.link external link style (common)
8.normalize (Automatic reset)

CSS Audio and video