JSFiddle - React, Tailwind, and code Playground

HTML

<h1>CSS: set COLUMN div heigth to 100%</h1>
<h2>stackoverflow.com/questions/13753090/css-set-div-heigth-to-100</h2>



<div class="container">
    <div class="client">Name: <br/>Phone:<br/>Emergency</div>
    <div class="contact">
        Contact 1<br/>
        Contact 2<br/>
        Contact 3<br/>
        Contact 4<br/>
        Contact 5<br/>
        Contact 6<br/>
        Contact 7<br/>
        Contact 8<br/>
    </div>
</div>

<div class="container">
    <div class="client">Name: <br/>Phone:<br/>Emergency</div>
    <div class="contact">
        Address 10<br/>
        Address 20<br/>
        Address 30<br/>
        Address 40<br/>
        Address 50<br/>
        Address 60<br/>
        Address 70<br/>
        Address 80<br/>
    </div>
</div>

CSS

.container {
    position: relative;
    display: table;
    width: 100%;
}

.container div {
    border: 2px solid red;
    vertical-align: top;
    height: 100%;
    overflow:auto;
    display: table-cell;
}
.container .client {
    width: 30%;
    display: table-cell;
 
}
.container .contact {
    width: 70%;
    display: table-cell;
}