1.

 

.clearfix:after {

content: ".";

display: block;

height: 0;

clear: both;

visibility: hidden;

}

/* Hides from IE-mac \*/

* html .clearfix {height: 1%;}

/* End hide from IE-mac */

2.

给父容器增加属性:overflow:hidden

3.

给父容器增加属性:display:table

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