#icone,#janela,#titulo-janela{position:absolute}body{font-family:arial}#janela{top:50%;left:50%;width:30em;height:10em;margin-top:-5em;margin-left:-15em;border:1px solid #000;background-image:repeating-linear-gradient(blue,#00008b 10%,#00f 20%);border-radius:10px 10px 0 1px;display:none;user-select:none;padding:2em .15em .15em;z-index:1}#sub-janela{position:relative;float:left;top:50%;left:50%;transform:translate(-50%,-50%)}#titulo-janela{bottom:9em;color:#fff;padding-left:5px}#conteudo-janela{background-color:#f5f5f5;padding:1em;width:28em;height:8em}#icone{font-size:50px;float:left}#mensagem{font-size:20px;text-align:center}