Flexible width of a button

Flexible width of a button

I am using below CSS for my button
.ui-button-text {
background-color:#3e9cbf !important;
font-family: Verdana, Arial, Helvetica, sans-serif;
font-size: 12px;
color: #F0F8FF !important;
width: 50px;
}
Here if you will check ,i am using width: 50px; but i want the width of
button shuold be flexible it should change width according to text size if
button text is Submit then button width will small but if text is
something like this Post Your Question now button width should change. How
can we achieve this with css