Edit in JSFiddle

/*
Techonolgy Quest;
creating a Circular menu is simple and completely depends on the 
"border-radius".
While creating circular menu always keep same value for height, width and border-radius.

Following id will define the dimensions for the menu, margin, padding width, height.
*/
#menucontainer {
    margin: 0px;
    padding: 0px;
    width: 100%;
    height: 90px;
}

/* Following selectors will define the color and the border radius for the menu*/
#menucontainer ul {
    list-style: none;
    margin: 0px;
    padding: 0px;
    
    
}
/* Following selector will define the style for individual menu or li tags. The following style gives them a look when the menus are not selected.
note that the position proerty is set to relative and dispaly is inline.
*/
#menucontainer ul li {
    list-style: none;
    margin: 10px;
    padding: 0px;
    background-color:#2CDF7B;
    position: relative;
    display: inline;
    text-align: center;
    /*Setting the height and width for the menu*/
    width: 90px;
    cursor:pointer;
    height: 90px;
    /*Setting the border-radius for the menu
    various prefix are added so it is supported in older version of
    browsers. For IE supported from IE-9+
    IMPORTANT: to keep the border radius height and width same to get circle.
    */
      -moz-border-radius: 90px;
    -webkit-border-radius: 90px;
    -khtml-border-radius: 90px;
    border-radius: 90px;
    /*Adding the box shadow to the menu*/
 box-shadow: 0 0 10px black;   
    -moz-box-shadow: 0 0 10px black;   
    -webkit-box-shadow: 0 0 10px black;   
    float: left;
}
/* Style for the anchor tag defined in the menu. 
*/
#menucontainer ul li a {
    
    margin: 10px;
    padding: 10px;
        background-color:transparent;
    display: block;
    text-decoration: none;
    text-align: center;
    font-family:"Times New Roman", "Arabic";
    font-size: 18px;
    color: #E3E3C0;


}
/* The hover effect is defined using the below selectors
For the opacity is used to create a semi-transperant look as a hover effect
*/

#menucontainer ul li:hover {
       list-style: none;
    margin: 10px;
    padding: 0px;
    opacity: 0.7;
    background-color:#2CDF7B;
    position: relative;
    display: block;
    width: 90px;
    text-align: center;
    cursor:pointer;
    height: 90px;
        /*Setting the border-radius for the menu
    various prefix are added so it is supported in older version of
    browsers. For IE supported from IE-9+
    IMPORTANT: to keep the border radius height and width same to get circle.
    */
      -moz-border-radius: 90px;
    -webkit-border-radius: 90px;
    -khtml-border-radius: 90px;
    border-radius: 90px;
 -moz-box-shadow: inset 0 0 10px black;   
    box-shadow: inset 0 0 10px black; 
    -webkit-box-shadow: inset 0 0 10px black; 
}
#menucontainer ul li:hover a {
    
    margin: 10px;
    padding: 10px;
        background-color:transparent;
    display: block;
    text-decoration: none;
    text-align: center;
    font-family:"Times New Roman", "Arabic";
    font-size: 18px;
    color: white;
}