.nav_menu{
    width: 100%;
    background-color: #42b5eb;
    height: 40px;
}

.nav_menu ul a{
    float: left;
    width: 100px;
    padding:0px 8px;
    height: 40px;
    text-align: center;
    line-height: 40px;
    vertical-align: middle;
    text-decoration: none;
    list-style-type: none;
    display: inline-block;
    color: #ffffff;
}

.nav_menu ul a:hover{
    color: 42b5eb;
    background-color: #F1F1F1;
}