.c-ontainer {
position: relative;
height: 200px;
width: 300px;
background-color: black;
color: white;
font-size: 24px;
line-height: 200px;
text-align: center;
}
.line {
position: absolute;
height: 1px;
width: 100%;
background-color: white;
animation: move 2s linear infinite;
animation-timing-function: cubic-bezier(0.1, 0.4, 0.5, 0.1);
}
@keyframes move {
from { top: 200px; }
to { top: 0px; }
}
/*--???布局--*/