Generated by SassMeister.com.

SassMeister-input.scss

// ----
// libsass (v3.3.2)
// ----

// Set sides and all as a list of booleans
$border-radius-list: (
    all  : (true, true, true, true),
    top  : (true true false false),
    bottom  : (false, false, true, true),
    left  : (true false false true),
    right  : (false, true, true, false),
);

@mixin border-radius ($side: all, $size: 5px) {
  // Grab Boolean list of values based on given $side parameter
  $bools: map-get($border-radius-list, $side);
  $rad-list:(); // Set value list as empty variable to be appended in each loop below
  @each $bool in $bools{
    // If value in loop is true append $rad-list with size parameter, else 0
    $rad-list: if($bool, append($rad-list,$size), append($rad-list,0px));
  }
  // Once loop is complete append the rad-list value to the corresponding property declaration.
    border-radius: $rad-list;
    -moz-border-radius: $rad-list;
    -webkit-border-radius: $rad-list;
}

#order-progress {
  display:100%;
  margin:0;
  li{
    &:first-child {
      @include border-radius(left);
    }
    &:last-child {
      @include border-radius(right);
    }
  }
}

SassMeister-output.css

#order-progress {
  display: 100%;
  margin: 0;
}

#order-progress li:first-child {
  border-radius: 5px 0px 0px 5px;
  -moz-border-radius: 5px 0px 0px 5px;
  -webkit-border-radius: 5px 0px 0px 5px;
}

#order-progress li:last-child {
  border-radius: 0px 5px 5px 0px;
  -moz-border-radius: 0px 5px 5px 0px;
  -webkit-border-radius: 0px 5px 5px 0px;
}