/* CSS */
body{
    background-color: #CCC;
    font-family: "Trebuchet MS", Verdana, Arial, Helvetica, sans-serif;
}
#login{
    width: 400px;
    height: 200px;
    border-radius: 10px;
    -ms-border-radius: 10px;
    -moz-border-radius: 10px;
    -webkit-border-radius: 10px;
    -khtml-border-radius: 10px;
    background-color: #FAFAFA;
    -moz-box-shadow: 0px 0px 10px 2px #888;
    -webkit-box-shadow: 0px 0px 10px 2px #888;
    box-shadow: 0px 0px 10px 2px #888;
    margin: 0 auto;
    position: relative;
    padding: 15px;
    /*opacity: 0;*/
}
#login .rectangle{
    background: #888;
    height: 50px;
    width: 400px;
    position: relative;
    left:-30px;
    float: left;
    -moz-box-shadow: 0px 0px 4px rgba(0,0,0,0.55);
    -khtml-box-shadow: 0px 0px 4px rgba(0,0,0,0.55);
    -webkit-box-shadow: 0px 0px 4px rgba(0,0,0,0.55);
    z-index: 100;
}
#login .rectangle h1, #login .rectangle h2{
    color: #FFF;
    font-size: 20px;
    text-shadow: #666 1px 1px 1px;
    padding-top: 6px;
    padding-left: 20px;
}
#login .rectangle h2{
    font-size: 14px;
    padding-top: 2px;
}
#login .triangle {
    border-color: transparent #888 transparent transparent;
    border-style: solid;
    border-width: 15px;
    height: 0px;
    width: 0px;
    position: relative;
    left: -45px;
    top: 35px;
    z-index: 1;
}

/* HTML */

<div id="login">

    <div class="rectangle">
        <h1>Accesso</h1>
        <h2>Por favor inicia sesión</h2>
    </div>
    <div class="triangle"></div>
    <div id="inputs">

    </div>

    <div id="footer">

    </div>

</div>