<p>example</p>
p{ width:150px; height:50px; color:#fff; background-color:#ccc; text-align:center; line-height:50px; margin:20px ; -webkit-transition: all 1s ease-in-out ; -moz-transition: all 1s ease-in-out ; -o-transition: all 1s ease-in-out ; transition: all 1s ease-in-out ; } p:hover{ width: 350px; }