Pure CSS Circle

HTML

<div class="circleBase type1">
    <div class="circle-text"></div>
</div>

CSS

.circleBase {
    -webkit-border-radius: 999px;
    -moz-border-radius: 999px;
    border-radius: 999px;
    behavior: url(PIE.htc);
}

.type1 {
    width: 100px;
    height: 100px;
    background: yellow;
    border: 1px solid black;
}

.circle-text {
    margin-left: auto;
    margin-right: auto;
}