CSS3のみでモーダルを作成

	/*モーダルウィンドウを動かしているcss*/

　.modal-wrapper:not(:target) {
		opacity: 0;
		visibility: hidden;
		transition: opacity .3s, visibility .3s;
	}

	.modal-wrapper:target {
		opacity: 1;
		visibility: visible;
		transition: opacity .4s, visibility .4s;
	}

<section>

	<style>
		a.modal-btn{
			color: #fff !important;
	  		background-color: #37b507;
	  		border-radius: 100vh;
	  		padding: 0.5em 3em;
		}

		.modal-btn:hover,
		a.modal-btn:hover {
			color: #fff !important;
			background: #8e8e8e;
		}

		.modal-wrapper {
			z-index: 999;
			position: fixed;
			top: 0;
			right: 0;
			bottom: 0;
			left: 0;
			padding: 40px 10px;
			text-align: center
		}

		.modal-wrapper:not(:target) {
			opacity: 0;
			visibility: hidden;
			transition: opacity .3s, visibility .3s;
		}

		.modal-wrapper:target {
			opacity: 1;
			visibility: visible;
			transition: opacity .4s, visibility .4s;
		}

		.modal-wrapper::after {
			display: inline-block;
			height: 100%;
			margin-left: -.05em;
			vertical-align: middle;
			content: ""
		}

		.modal-wrapper .modal-window {
			box-sizing: border-box;
			display: inline-block;
			z-index: 20;
			position: relative;
			width: 70%;
			max-width: 600px;
			padding: 30px 30px 15px;
			border-radius: 2px;
			background: #fff;
			box-shadow: 0 0 30px rgba(0, 0, 0, .6);
			vertical-align: middle
		}

		.modal-wrapper .modal-window .modal-content {
			max-height: 80vh;
			overflow-y: auto;
			text-align: left
		}

		.modal-overlay {
			z-index: 10;
			position: absolute;
			top: 0;
			right: 0;
			bottom: 0;
			left: 0;
			background: rgba(0, 0, 0, .8)
		}

		.modal-wrapper .modal-close {
			z-index: 20;
			position: absolute;
			top: 0;
			right: 0;
			width: 35px;
			color: #95979c !important;
			font-size: 20px;
			font-weight: 700;
			line-height: 35px;
			text-align: center;
			text-decoration: none;
			text-indent: 0
		}

		.modal-wrapper .modal-close:hover {
			color: #2b2e38 !important
		}

	</style>

	<a href="#modal-01" class="modal-btn">
		Clickして確認
	</a>
	<div class="modal-wrapper" id="modal-01">
		<a href="#!" class="modal-overlay"></a>
		<div class="modal-window">
			<div class="modal-content">
				<h4>Modal window</h4>
				<p>
				Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. 
				</p>
			</div>
			<a href="#!" class="modal-close">×</a>
		</div>
	</div>

</section>