Responsive Navigation menu not working

Question

I am trying to design a responsive nav bar. I dont know much about css3. Except for Tablet, nav bar works fine. Please help me what I am missing for tablet size. Do I need to add media query for tablet size? Or any changes needs to be done in nav tags

<nav class="clearfix">
    <ul class="clearfix">
         <li><a href="#">Home</a></li>
         <li><a href="#">Menu1</a></li>
         <li><a href="#">Menu1</a></li>
         <li><a href="#">Menu1</a></li>
         <li><a href="#">Menu1</a></li>
         <li><a href="#">Menu1</a></li> 
         <li><a href="#">Menu1</a></li> 
         <li><a href="#">Menu1</a></li> 
    </ul>
    <a href="#" id="pull">Menu</a>
</nav>

Here is the css for that nav

nav {
    height: 40px;
    width: 100%;
    background: #455868;
    font-size: 11pt;
    font-family: 'PT Sans', Arial, sans-serif;
    font-weight: bold;
    position: relative;
    border-bottom: 2px solid #283744;
}
nav ul {
    padding: 0;
    margin: 0 auto;
    width: 80%;
    height: 40px;
}
nav li {
    display: inline;
    float: left;
}
nav a {
    color: #fff;
    display: inline-block;
    width: 100px;
    text-align: center;
    text-decoration: none;
    line-height: 40px;
    text-shadow: 1px 1px 0px #283744;
}
nav li a {
    border-right: 1px solid #576979;
    box-sizing:border-box;
    -moz-box-sizing:border-box;
    -webkit-box-sizing:border-box;
}
nav li:last-child a {
    border-right: 0;
}
nav a:hover, nav a:active {
    background-color: #8c99a4;
}
nav a#pull {
    display: none;
}

/*Styles for screen 600px and lower*/
@media screen and (max-width: 600px) {
    nav { 
        height: auto;
    }
    nav ul {
        width: 100%;
        display: block;
        height: auto;
    }
    nav li {
        width: 50%;
        float: left;
        position: relative;
    }
    nav li a {
        border-bottom: 1px solid #576979;
        border-right: 1px solid #576979;
    }
    nav a {
        text-align: left;
        width: 100%;
        text-indent: 25px;
    }
}

/*Styles for screen 515px and lower*/
@media only screen and (max-width : 480px) {
    nav {
        border-bottom: 0;
    }
    nav ul {
        display: none;
        height: auto;
    }
    nav a#pull {
        display: block;
        background-color: #283744;
        width: 100%;
        position: relative;
    }
    nav a#pull:after {
        content:"";
        background: url('nav-icon.png') no-repeat;
        width: 30px;
        height: 30px;
        display: inline-block;
        position: absolute;
        right: 15px;
        top: 10px;
    }
}

/*Smartphone*/
@media only screen and (max-width : 320px) {
    nav li {
        display: block;
        float: none;
        width: 100%;
    }
    nav li a {
        border-bottom: 1px solid #576979;
    }
}
.clearfix:before,
.clearfix:after {
    content: " ";
    display: table;
}
.clearfix:after {
    clear: both;
}
.clearfix {
    *zoom: 1;

Answer 1

You could try this: http://jsfiddle.net/98jxL/2/

I have added a new media query for up to 1000px. It will distribute your menu items evenly over the screen width. This solution is based on you having 8 menu items.

/*Styles for screen 1000px and lower*/
@media screen and (max-width: 1000px) {
    nav ul {
        width: 100%;
    }

    nav li {
        width: 12.5%;
    }

    nav a {
        width: 100%;
    }
}