body {
    font-family: 'Helvetica Neue','Helvetica', Arial, sans-serif;
}
 
.main-content {
    height: 800px;
    width: 1000px;
    margin: 0 auto;
}
 
.overlay-bg {
    display: none;
    position: absolute;
    top: 0;
    left: 0;
    height:100%;
    width: 100%;
    cursor: pointer;
    z-index: 1000; /* high z-index */
    background: #000; /* fallback */
    background: rgba(0,0,0,0.75);
    
}

    .overlay-content {
        display: none;
        background: #fff;
        padding: 1%;
        width: 61%;
        position: absolute;
        top: 15%;
        left: 38%;
        margin: 0 0 0 -20%; /* add negative left margin for half the width to center the div */
        cursor: default;
        z-index: 10001;
        border-radius: 4px;
        box-shadow: 0 0 5px rgba(0,0,0,0.9);
        
    }
 
    .close-btn {
        cursor: pointer;
        border: 1px solid #333;
        padding: 1% 3%;
        background: #a9e7f9; /* fallback */
        background: -moz-linear-gradient(top,  #a9e7f9 0%, #77d3ef 4%, #05abe0 100%);
        background: -webkit-gradient(linear, left top, left bottom, color-stop(0%,#a9e7f9), color-stop(4%,#77d3ef), color-stop(100%,#05abe0));
        background: -webkit-linear-gradient(top,  #a9e7f9 0%,#77d3ef 4%,#05abe0 100%);
        background: -o-linear-gradient(top,  #a9e7f9 0%,#77d3ef 4%,#05abe0 100%);
        background: -ms-linear-gradient(top,  #a9e7f9 0%,#77d3ef 4%,#05abe0 100%);
        background: linear-gradient(to bottom,  #a9e7f9 0%,#77d3ef 4%,#05abe0 100%);
        border-radius: 4px;
        box-shadow: 0 0 4px rgba(0,0,0,0.3);
        float:right;
        margin:-30px 0 0 -20px;
        font-size:large;
        font-weight:bold;
        color:white;
    }
    .close-btn:hover {
        background: #05abe0;
        color:red;
    }








/* media query for most mobile devices */
@media only screen and (min-width: 0px) and (max-width: 480px){
 
    .overlay-content {
        width: 96%;
        margin: 0 2%;
        left: 0;
    }
}