*{
    margin: 0;
    padding: 0;
}
html, body { height: 100%;}
body {
    background: -moz-linear-gradient(left bottom, rgb(153,217,234) 40%,
    rgb(36,147,174) 70%, rgb(17,68,81) 95%);
    background: -ms-linear-gradient(left bottom, rgb(153,217,234) 40%,
    rgb(36,147,174) 70%, rgb(17,68,81) 95%);
    background: -o-linear-gradient(left bottom, rgb(153,217,234) 40%,
    rgb(36,147,174) 70%, rgb(17,68,81) 95%);
    background: -webkit-linear-gradient(left bottom, rgb(153,217,234) 40%,
    rgb(36,147,174) 70%, rgb(17,68,81) 95%);
    background: linear-gradient(left bottom, rgb(153,217,234) 40%, rgb(36,147,174)
    70%, rgb(17,68,81) 95%);
    color: white;
    font-family: Arial;
    font-size: 16px;
    margin: 0;
    text-shadow: 1px 1px 0 rgba(0,0,0,.3);
}
/* Estilos para el área donde se mostrará la imagen de la figura geométrica */
#figura {
margin-top: 10%;
}
header {
margin-top: 5%;
}
div {
display: block;
height: 120px;
margin: 0 auto;
width: 120px;
}
header h1 {
color: #fff;
font: Bold 3.2em Tahoma,Helvetica,"Liberation Sans",sans-serif;
text-align:center;
text-shadow: 0 0 2px #ccc,
-1px -1px 0 hsl(80, 70%, 35%),
-2px -2px 1px hsl(80, 70%, 35%),
-2px -2px 2px hsl(80, 10%, 15%);
}
img{
display: block;
height: 400px;
margin: 0 auto;
width: 600px;
}