Add empty space between div's content and bottom border

Question

I am attempting to add a bottom border to a div for the purpose of a navigation bar. The effect I am trying to achieve:

Answer 1

demo

new css:

.container {
}

.container .item {
  float: left;
  list-style-type: none;
  margin: 0 1px;
  border-bottom: 8px solid red;  
}

  .container .item a {
    color: black;
    text-decoration: none;
    background-color: green;
    width: 50px;
    font-size: 13px;
    text-align: center;
    font-weight: bold;
    display: table-cell;
    vertical-align: middle;
    height: 40px; 
          border-bottom: 4px solid white;  
  }

    .container .item a.current {
    }