= || [ / ]? || || || ||

= || [ / ]? || || || || ||

= | none

= [ left | center | right | top | bottom | ] | [ left | center | right | ] [ top | center | bottom | ] | [ center | [ left | right ] ? ] && [ center | [ top | bottom ] ? ]

= [ | auto ]{1,2} | cover | contain

= repeat-x | repeat-y | [ repeat | space | round | no-repeat ]{1,2}

= scroll | fixed | local

= content-box | padding-box | border-box

=

= |

= |

= |

= url( * ) |

= src( * )