Aquí teneis el codigo.
Código HTML:
body {
background: #007d7d;
filter:progid:DXImageTransform.Microsoft.Gradient(GradientType=0, StartColorStr='#007d7d', EndColorStr='#005697');
background: -moz-linear-gradient(top, #007d7d, #005697);
background: -webkit-gradient(linear, left top, left bottom, from(#007d7d), to(#005697));
background: -o-linear-gradient(#007d7d, #005697);
background: linear-gradient(top, #007d7d, #005697);
width: 100%;
height: 100%;
}