基础设置
background-image: radial-gradient(shape size at position, start-color, ..., last-color);
background: #58a;
background-image: radial-gradient(
ellipse 90px 60px at center center,
red 5%,
green 15%,
transparent 60%
);
最后一个颜色会铺满屏幕,但是如果不希望如此可以设置transprent作为最后一个颜色