JSFiddle - React, Tailwind, and code Playground

HTML

<div id="message-1" class="msgbox" style="display: none;"><div class="guestwarn"><a href="#" class="close" onclick="closeBox('message-1'); return false;" title="Close"></a>
Testo</div></div>

CSS

div.guestwarn {
    background: {vb:raw vboptions.guest_warn_color};
    color: {vb:raw vboptions.guest_warn_text_color};
    max-width:280px;
    min-height:18px;
    padding:0 5px 3px;
    position:fixed;
    right: {vb:raw vboptions.guest_var_width}%;
    top: {vb:raw vboptions.guest_var_height}%;
    padding: 10px 15px;
    position: fixed;
    z-index: 10;
    font-size:12px;
    -moz-border-radius: 8px;
    -webkit-border-radius: 8px;
    filter:alpha(opacity={vb:raw vboptions.guest_var_opacity}); 
    -moz-opacity:.{vb:raw vboptions.guest_var_opacity};
    opacity:.{vb:raw vboptions.guest_var_opacity};
    -moz-box-shadow:5px 5px 5px #191919;
    -webkit-box-shadow:5px 5px 5px #191919;
     box-shadow:5px 5px 5px #191919;
 /*display: none;*/
}
}
.close {
    float: right;
    background: transparent url({vb:raw vboptions.guest_warn_image});
    width: 22px;
    height: 22px;
}

JavaScript

function closeBox(toClose) {
    document.getElementById(toClose).style.display = "none";
    setCookie(toClose, "closed", 50);
}
function setCookie(cName, value, expiredays) {
    var expDate = new Date();expDate.setDate(expDate.getDate()+expiredays);
    document.cookie=cName + "=" + escape(value) + ";expires=" + expDate.toGMTString();
}
function loadMsg(msgClass) {
    msg = document.getElementsByTagName("div");
    for (i=0; i<msg.length; i++){
        if(msg[i].className == msgClass) {
            if(document.cookie.indexOf(msg[i].id) == -1) {
                msg[i].style.display = "block";
            }
        }
    }
}
window.onload=function(){
    loadMsg('msgbox'); 
                        }