.background {
  background-color: black;
  position: relative;
  width: 100vw;
  height: 100vh;
  margin: auto;
}

.bgm-cd {
	position: fixed;
	width: 56px;
	height: 56px;
	border-radius: 50%;
	right: 2%;
	bottom: 2%;
	border: 5px white solid;
	overflow: hidden;
	background-color: rgba(255, 255, 255, 0.25);
	backdrop-filter: blur(3px);
	display: none;
	transition: 0.5s ease opacity;
	animation-name: hide;
	animation-fill-mode: forwards;
	animation-duration: 0.5s;
	animation-delay: 5s;
	animation-timing-function: ease;
}
.bgm-cd::before {
	content: '';
	position: absolute;
	width: 100%;
	height: 100%;
	left: 0;
	right: 0;
	top: 0;
	bottom: 0;
	margin: auto;
	transform: translateY(100%);
	background-color: deepskyblue;
	animation: 5s linear forwards waiting;
}
@keyframes hide {
	from {
		opacity: 1;
	}
	to {
		opacity: 0;
	}
}
@keyframes waiting {
	from {
		transform: translateY(100%);
	}
	to {
		transform: translateY(0%);
	}
}