.container {
background:#cddde3; /* background of round piece */
color:#fff; /* background outside of corner */
margin:0 15px; /* left and right margin */
}

.rtop, .rbottom{
display:block;
background:#fff;
}
.rtop *, .rbottom *{
display: block;
height: 1px;
overflow: hidden;
background:#cddde3;
}

.r1{margin: 0 5px}
.r2{margin: 0 3px}
.r3{margin: 0 2px}
.r4{margin: 0 1px; height: 2px}