我正在尝试使用@keyframes 为背景交换设置动画。背景是径向渐变。背景发生变化，但没有动画。
#mydiv {
background: radial-gradient(circle at 90% 80%, #ff0000, #4d0019);
width: 100%;
height: 1246px;
position: relative;
overflow: hidden;
animation: background-gradient 5s;
animation-iteration-count: infinite;
backface-visibility: hidden;
animation-timing-function: ease-in-out;
}
@-webkit-keyframes background-gradient {
0% {background: radial-gradient(circle at 90% 80%, #ff0000, #4d0019);}
25% {background: radial-gradient(circle at 90% 80%, #993399, #4d0019);}
50% {background: radial-gradient(circle at 90% 80%, #3333cc, #4d0019);}
75% {background: radial-gradient(circle at 90% 80%, #00ffcc, #4d0019);}
100% {background: radial-gradient(circle at 90% 80%, #cc9900, #4d0019);}
}
@keyframes background-gradient {
0% {background: radial-gradient(circle at …