background: linear-gradient(to right,red,orange,yellow, green, blue,indigo,violet); 

background: linear-gradient(top,#ccc, #000);

background: radial-gradient(red, yellow, rgb(30, 144, 255));
　　　　　　radial-gradient(center, ellipse cover, #5170ad 0%, #355493 100%)
　　　　　　

background-image: radial-gradient(ellipse farthest-corner at 45px 45px , #00FFFF 0%, rgba(0, 0, 255, 0) 50%, #0000FF 95%);

background-image: radial-gradient(16px at 60px 50% , #000000 0%, #000000 14px, rgba(0, 0, 0, 0.3) 18px, rgba(0, 0, 0, 0) 19px);

background: repeating-linear-gradient(to top left, red, red 5px, white 5px, white 10px);

gradient