What this does is extend the margin on the top of the cleared box, pushing it down until it "clears" the bottom of the float.

这是将被清除盒的顶部边距扩展，将其向下推直到清理浮动的底部。

youdao

What this does is extend the margin on the top of the cleared box, pushing it down until it "clears" the bottom of the float.

这是将被清除盒的顶部边距扩展，将其向下推直到清理浮动的底部。

youdao