/* ここはレイアウトなのでボタンとは関係ない */
* {
  margin: 0;
}

.layout {
  display: flex;
  justify-content: center;
  align-items: center;
  flex-direction: column;
  gap: 50px;
  width: 100%;
  height: 100vh;
}

/* ここからボタンのCSS */
@keyframes left-circle {
  0% {
    left: -20px;
    width: 20px;
    height: 20px;
  }
  50% {
    left: 50%;
    width: 20px;
    height: 20px;
  }
  100% {
    left: 50%;
    width: calc(240px * 1.5);
    height: calc(240px * 1.5);
  }
}

@keyframes right-circle {
  0% {
    right: -20px;
    width: 20px;
    height: 20px;
  }
  50% {
    right: 50%;
    width: 20px;
    height: 20px;
  }
  100% {
    right: 50%;
    width: calc(240px * 1.5);
    height: calc(240px * 1.5);
  }
}

.button {
	a {
		position: relative;
		display: flex;
		justify-content: center;
		align-items: center;
		width: 240px;
		height: 50px;
		font-size: 16px;
		text-decoration: none;
		color: #5cc0ef;
		border: 1px solid #5cc0ef;
		overflow: hidden;
		//hoverを辞めたときのアニメーション速度
		transition: all 0.5s;

		&::before,
		&::after {
			content: '';
			position: absolute;
			z-index: -1;
			top: 50%;
			width: 20px;
			height: 20px;
			background-color: #5cc0ef;
			border-radius: 50%;
			transform: translate(-50%, -50%);
		}

		&::before {
			left: -20px;
		}

		&::after {
			right: -20px;
			transform: translate(50%, -50%);
		}

		&:hover {
			color: #fff;
			//hoverしたときのアニメーション速度
			transition: all 0.4s 0.4s;

			&::before {
				animation: left-circle 0.8s both alternate;
			}

			&::after {
				animation: right-circle 0.8s both alternate;
			}
		}
	}
}