I think this is what you are looking for..
.border1{
width:100px;
height:100px;
border-left: 10px solid #ccc;
}
.border2{
width: 100px;
height: 100px;
display: block;
margin-left: 15px;
border-left: 3px solid #ccc;
}
<div class="border1">
<div class="border2"></div>
</div>
Check it and let me know if you want any thing else..
2
solved How to make double border on left only with thick outside and thin inside [duplicate]