Inner left-floating div's do not expand the container div vertically

Question

I have a container div with the following attributes:

#cat_container{
margin:0;
padding:5px;
border:1px solid red;
min-height:200px;
}

Insi

Answer 1

container{
    overflow: auto;
}

Insert the following at the end, before the enclosing the container

The container will automatically expand to the the last clear:both