body{font-family:Arial;background:#f4f4f4;padding:30px}
form{background:#fff;padding:20px;max-width:520px}
input,select,button{width:100%;padding:10px;margin-top:10px}
.hidden{display:none}
.popup{display:none;position:fixed;top:0;left:0;width:100%;height:100%;background:rgba(0,0,0,.6)}
.popup-content{background:#fff;padding:20px;max-width:350px;margin:15% auto;text-align:center}