.g_clr:after { content:" "; display:block; height:0px; clear:both; visibility:hidden; }这是css的一串代码,请问g_clr:after这个是什么意思,统称为什么?

.g_clr:after { content: ; display:block; height:0px; clear:both; visibility:hidden; }这是css的一串代码,请问g_clr:after这个是什么意思,统称为什么? 英语翻译this essay begins with the introduction of defintion and classification of context theories.context covers three classifications that refer to linguistic context,situational context and cultural context.after detailed description of conte Il Conte D'Alba 中文的红酒名称是什么? Notre amour est beau comme un conte de fées à droite... “My great concern is not whether you have failed,but whether you are conte after after after after After after after After after after after after after