border: 10px solid #25C063;
border-top: 10px solid #25C063; border-right: 10px solid #25C063; border-buttom: 0px solid #25C063; border-left: 0px solid #25C063;
<div class="box a2z_border"></div>
<style>
.box{
height:150px;
width:250px;
background-color:#283e8a;
}
.a2z_border{
border: 10px solid #25C063;
border-top: 10px solid #25C063;
border-right: 10px solid #25C063;
border-buttom: 0px solid #25C063;
border-left: 0px solid #25C063;
}
</style>