border radius .less doesn't work - html

Question

I have a site and I want to use .less instead of .css but I have a problem with border radius, if I copy the same code into a css file work in .less doens.'t work, It doesn't take my radius and the div is rectangular. I have used a compiler and It gives me 0 error. I don't know if is a problem of compatibility. this is my code that doesn't work in less but in
css work:
.colLeft{
position:absolute;
top:0;
left:0;
background:#fff;
height:100%;
width:24%;
z-index:0;
}
.colCenter{
position:absolute;
top:0;
left:18%;
height: 100%;
width: 68%;
background: #ccc;
border-left: 1px solid #333;
border-radius: 50px 0px 0px 50px / 250px 0px 0px 250px;
z-index:100;
overflow:hidden;
-moz-box-shadow: 1px 1px 1px #000;
-webkit-box-shadow: 1px 1px 1px #000;
box-shadow: 1px 1px 1px #000;
}
.colRight{
position:absolute;
top:0;
left:81%;
background:#fff;
height:100%;
width:18%;
z-index:1000;
border-left: 1px solid #333;
border-radius: 50px 0px 0px 50px / 250px 0px 0px 250px;
}
Html:
<div class="colLeft" id="one">
</div>
<div class="colCenter" id="two">
<div class="content">
<div class="img_background">
<img src="img/sfondi/<?php echo (basename($_SERVER['HTTP_REFERER'],'.php')); ?>.jpg" alt="" class="old_img"/>
</div>
</div>
</div>
</div>
<div class="colRight" id="three">
index
NEXT
</div>

Answer 1

border-radius: 50px 0px 0px 50px / 250px 0px 0px 250px;
should be
border-radius: 50px 0px 0px ~"50px / 250px" 0px 0px 250px;
otherwise you get a division.
Less is in the process of introducing a policy of only doing division inside brackets so that valid css is unaltered, but this will be in a future release (e.g. maybe 1.4.0)