title: Can't get the CSS nth term to work
body: <p>I realise i have posted couple of questions on floating , nearly near just have one more question on the nth term..</p>
  
  <p>I am trying to adjust some responsive floats using the nth term and widths but im struggling to change the following. </p>
  
  <p>When you reduce the screen size to under 600px i need the two boxes to be displayed as 3 equally boxes, not two. I am struggling to accomplish this using widths and use of nth term.</p>
  
  <p>Im trying to achieve the following. </p>
  
  <pre class="lang-none prettyprint-override"><code>4 boxes above 900px +px
  3 boxes above 600px - 900px
  2 boxes 460px - 600px
  1 box 0- 460px
  </code></pre>
  
  <p>If anyone could help it would be great. </p>
  
  <p><a href="http://jsfiddle.net/sFApC/" rel="nofollow noreferrer">http://jsfiddle.net/sFApC/</a></p>
  
  <pre class="lang-css prettyprint-override"><code>.display-box{
    position: relative;
    clear: left;
    background: #fff;
    -webkit-border-radius: 4px;
    -moz-border-radius: 4px;
    border-radius: 4px;
    -webkit-box-shadow: 0 1px 2px rgba(0,0,0,0.09);
    -moz-box-shadow: 0 1px 2px rgba(0,0,0,0.09);
    box-shadow: 0 1px 2px rgba(0,0,0,0.09);
    padding: 10px 10px 30px 10px;
    border: 1px solid #d1d1d1;
    }
    .display-box:hover{
      -webkit-box-shadow: 0 10px 6px -6px #b5b5b5;
      -moz-box-shadow: 0 10px 6px -6px #b5b5b5;
      box-shadow: -1px 1px 11px 2px #b5b5b5;
      cursor: pointer;
      border: 1px solid #c6c6c6 ;
    }
    .display-user{
      max-width: 20px !important;
      margin-bottom: 10px;
      float: left;
    }
    .user-name{
      float: left;
      font-weight: bold;
      margin: 6px 0 0 6px;
      }
      .content-upload img{
        height: 20%;
      }
  
  #upload-container {
    width: 100%;
    max-width: 970px;
    margin: 0 auto;
    margin-top: 20px;
  }
  #upload-container ul {
    width: 100%;
    *zoom: 1;
  }
  #upload-container ul li {
    float: left;
    margin-right: -100%;
    width: 93%;
  }
  
  #upload-container ul li a:hover {
    text-decoration: none;
  }
  
  #upload-container ul li span {
    font-size: 16px;
    line-height: 22px;
    display: block;
    padding-bottom: 30px;
  }
  #upload-container ul li img {
    width: 100%;
  }
  #upload-container ul li:nth-child(1n+1) {
    margin-left: 0%;
    margin-bottom: 5.85%;
    clear: both;
    overflow: hidden;
    *zoom: 1;
  }
  
  @media screen and (min-width: 460px) {
    #upload-container ul li {
      float: left;
      margin-right: -100%;
      width: 42.08%;
    }
    #upload-container ul li span {
      padding-bottom: 10px;
    }
    #upload-container ul li:nth-child(2n+1) {
      margin-left: 0%;
      margin-bottom: 3.85%;
      clear: both;
      overflow: hidden;
      *zoom: 1;
    }
    #upload-container ul li:nth-child(2n+2) {
      margin-left: 51.93%;
      margin-bottom: 3.85%;
      clear: none;
    }
  }
  @media screen and (min-width: 600px) {
    #upload-container ul li {
      float: left;
      margin-right: -100%;
      width: 45.08%;
    }
    #upload-container ul li span {
      padding-bottom: 10px;
    }
    #upload-container ul li:nth-child(2n+1) {
      margin-left: 0%;
      margin-bottom: 3.85%;
      clear: both;
      overflow: hidden;
      *zoom: 1;
    }
    #upload-container ul li:nth-child(2n+2) {
      margin-left: 51.93%;
      margin-bottom: 3.85%;
      clear: none;
    }
  }
  
  @media screen and (min-width: 900px) {
    #upload-container ul li {
      float: left;
      margin-right: -100%;
      width: 20.8%;
    }
    #upload-container ul li span {
      padding-bottom: 0px;
    }
    #upload-container ul li:nth-child(4n+1) {
      margin-left: 0%;
      margin-bottom: 3.85%;
      clear: both;
      overflow: hidden;
      *zoom: 1;
    }
    #upload-container ul li:nth-child(4n+2) {
      margin-left: 25.96%;
      margin-bottom: 3.85%;
      clear: none;
    }
    #upload-container ul li:nth-child(4n+3) {
      margin-left: 51.93%;
      margin-bottom: 3.85%;
      clear: none;
    }
    #upload-container ul li:nth-child(4n+4) {
      margin-left: 77.89%;
      margin-bottom: 3.85%;
      clear: none;
    }
  }
  </code></pre>
  
  <p><img src="https://i.stack.imgur.com/BJeg5.png" alt="enter image description here"></p>