<div class="container">
<div class="element">
This element is centered. No matter how its size changes, it will always be centered horizontally and vertically inside its container.
</div>
</div>
body {
background-color: #F5F5F5;
color: #555;
font-size: 1.1em;
font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
}
.container {
max-width: 800px;
margin: 3em auto;
background-color: white;
height: 500px;
border: 10px solid #594255;
-webkit-display: -webkit-box;
-webkit-display: -webkit-flex;
display: -webkit-box;
display: -ms-flexbox;
display: flex;
-webkit-align-items: center;
-webkit-box-align: center;
-ms-flex-align: center;
align-items: center;
-webkit-justify-content: center;
-webkit-box-pack: center;
-ms-flex-pack: center;
justify-content: center;
}
.element {
background-color: #594255;
color: white;
width: 250px;
padding: 20px;
}