CSS: centering a block without a stated width

by gabrieleromanato

HTML

<div id="container">
    <div id="center">
            Lundium amet ac auctor lundium a. 
            Urna odio enim! Porttitor?
    </div>
</div>

CSS

#container {
    margin: 1em;
    text-align: center;
}

#center {
    background: silver;
    display: inline-block;
    padding: 1em;
    text-align: left;
}