.box {
    display:inline-block;
    }
    
.content {
    width:300px;
    height:200px;
    border:solid black 1px;
    }
    
.rb {
    width:6px;
    height:6px;
    border:solid black 1px;
    background-color:white;
}
    
.tl {
    position:absolute;
        margin-left:-3px;
    margin-top:-3px;
    cursor:nw-resize;
    }

.tr {
    float:right;
    border:solid;
    }