File: example.css

/* 
    This is just a dummy css
*/

.mainnav ul {
    list-style:none;
}

.mainnav li {
    float:left;
    padding:10px;
    margin:5px;
}

.subnav {
    margin-left:55px;
    min-width: 400px;
    width:400px;
    margin-top:-15px;
    position:absolute;
    z-index:20;
    background:#fff;
}

.subnav div {
    border:2px solid fuchsia;
    padding:10px; 
}

.main-content {
    margin-left:55px;
}

/* Clear Floated Elements
----------------------------------------------------------------------------------------------------*/


.clear {
    clear: both;
    display: block;
    overflow: hidden;
    visibility: hidden;
    width: 0;
    height: 0;
}


.clearfix:after {
    clear: both;
    content: ' ';
    display: block;
    font-size: 0;
    line-height: 0;
    visibility: hidden;
    width: 0;
    height: 0;
}

.clearfix {
    display: inline-block;
}

* html .clearfix {
    height: 1%;
}

.clearfix {
    display: block;
}