/* 清除浮动塌陷问题 */
.clearfix:after {
 clear: both;
}

.clearfix:after,
.clearfix:before {
 content: " ";
 display: table;
}

/* 清除浮动塌陷问题 */ .clearfix:after { clear: both; } .clearfix:after, .clearfix:before { content: " "; display: table; }

HTML清楚塌陷问题