<div class="button06">ボタン06</div>
.button06 {
overflow: hidden;
position: relative;
z-index: 1;
background: #313131;
color: #fff;
}
.button06:before {
content: "";
width: 100%;
height: 100%;
background: #006400;
position: absolute;
z-index: -1;
top: 0;
right: 100%;
animation: btn06 1.5s ease-in-out infinite;
}
@keyframes btn06 {
0% {
right: 100%;
}
50% {
right: 0%;
}
100% {
right: 0%;
}
}