how to make two Div same height

HTML

<div class="container">
    <div class="column-one">Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.
    </div>
    <div class="column-two">When an unknown printer took a galley of type and scrambled it to make a type specimen book.
    </div>
</div>


<div class="container2">
    <div class="column-one-1">Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book.
    </div>
    <div class="column-two-2">When an unknown printer took a galley of type and scrambled it to make a type specimen book.
    </div>
</div>

CSS

.container{
    display:flex; /* make child div same height */
}

.container div{
    float:left;
    width:49%;
    border:1px solid #666666
}

.column-one{
    margin-right:1%;
}

.container2{
    display:table; /* make child div same height */
}

.container2 div{
    display:table-cell;
    float:none;
    width:49%;
    border:1px solid #666666;
    vertical-align: top;
}

.column-one-1{
    margin-right:1%;
}