.formulario h2 {
    background-color: lightskyblue;
    text-shadow: 0 2px 2px darkgrey;
    border-radius: 5px;
    color: white;
 font-family: sans-serif;
 font-size: 20px;
 padding: 5px;
 width: 433px;
}
.required:after{
content: '*';
color: red;
}
/*--- estilos para los ul y li del formulario ---*/
.formulario ul {
 width:750px;
 list-style-type:none;
margin:0px;
padding:0px;
}
.formulario li{
padding:12px;
border-bottom:1px solid #eee;
}
.formulario label {
 color: #555555;
 display: inline-block;
 float: left;
 font-family: sans-serif;
 font-size: 13px;
 font-weight: bold;
 margin-top: 3px;
 padding: 3px;
 width: 90px;
}
.formulario input {
height:20px;
width:220px;
padding:5px 8px;
}
.formulario textarea {
padding:8px;
width:300px;
}
.formulario button {
margin-left:90px;
}

/*----- estilos visuales de los elementos --------*/
.formulario input, .formulario textarea {
border:1px solid #aaa;
border-radius: 5px;
color: #888;
font-size: 12px;
 /*----- para ralentiza el que se haga grande la caja --------*/
padding-right:30px;
-moz-transition: padding .25s;
-webkit-transition: padding .25s; 
-o-transition: padding .25s;
transition: padding .25s;
}
.formulario input:focus, .formulario textarea:focus {
background: #fff;
border:1px solid #555;
box-shadow: 0 0 3px #aaa;
padding-right:120px;
}
/* === Estilos de Validacion === */
.formulario input:valid, .formulario textarea:required:valid {
    box-shadow: 0 0 5px #5cd053;
    border-color: #28921f;
    }
    .formulario input:required:invalid, .formulario textarea:required:invalid {
    box-shadow: 0 0 5px #d45252;
    border-color: #b03535
    }
/* === Estilos del boton de Envio === */
button.submit {
 padding: 9px 17px;
 font-family: Helvetica, Arial, sans-serif;
 font-weight: bold;
 line-height: 1;
 color: #444;
 border: none;
 background-color: #fff;
 border: 1px solid #f1f1f1;
 border-radius: 10px;
 box-shadow: 0 1px 2px rgba(0, 0, 0, 0.5);
}
button.submit:hover {
opacity:.55;
cursor: pointer;
color: red;
}
button.submit:active {
border: 5px solid #222;
box-shadow: 0 0 10px 5px #444 inset;
}