编程2.7为什么动不了 应该怎么做

<style type="text/css">
div{
width: 800px;
height: 400px;
border: 1px solid black;
border-radius: 50%;
animation-name: inner;
animation-duration: 5s;
animation-delay: 2s;
animation-timing-function: linear;
}
p{
margin-top: 150px;
font-size: 48px;
font-weight: bolder;
text-align: center;
}
@keyframes inner{
from { transform: translateX(0)};
to { transform: translateX(25px) };
}

</style>