你可以用radial-gradient.
body, html {
width: 100%;
height: 100%;
margin: 0;
background: -webkit-radial-gradient(center, ellipse, #2D84A7 5%, #0D354E);
background: -moz-radial-gradient(center, ellipse, #2D84A7 5%, #0D354E);
background: radial-gradient(center, ellipse, #2D84A7 5%, #0D354E);
}Run Code Online (Sandbox Code Playgroud)