问题
is -negative margin or padding are invalid CSS aaccording to W3C ?
回答1:
According to Cascading Style Sheets Level 2 Revision 1 (CSS 2.1) Specification - 8.4 Padding properties, negative margin values are valid, negative padding values are not:
Unlike margin properties, values for padding values cannot be negative
来源：https://stackoverflow.com/questions/1623163/is-negative-margin-or-padding-invalid-css-according-to-w3c