径向渐变

        #box {
            width: 200px;
            height: 200px;
            background-image: radial-gradient(farthest-side at 50% 50%, red, yellow , green);
        }

image.png

        #box {
            width: 200px;
            height: 200px;
            background-image: repeating-radial-gradient(farthest-side at 50% 50%, red, yellow 10%, green 15%);
        }

image.png