font:[font-style] [font-weight] [font-size] / [font-height] [font-family]
background样式简写:
background:[background-color] [background-image] [background-repeat] [background-position] / [background-size]
border样式简写:
border:[border-width] [border-style] [border-color]
其中font和background的样式属性顺序不可换,且"/"不可忽略,border的样式属性的顺序可任意。