<ul class="example">
	<li>1</li>
	<li>2</li>
	<li>3</li>
	<li>4</li>
</ul>

* {
	box-sizing: border-box;
}
body {
	min-height: 100vh;
	margin: 0;
	padding: 0;
	display: flex;
	justify-content: center;
	align-items: center;
}
ul {
	padding: 0;
	margin: 0;
}
li {
	line-height: 50px;
	width: 50px;
	background: #eee;
	margin: 10px 0;
	text-align: center;
	list-style-type: none;
}
li:nth-child(1) {
	background: #a0dde2;
}
li:nth-child(2) {
	background: #e2a0b4;
}
li:nth-child(3) {
	background: #eec496;
}
li:nth-child(4) {
	background: #a0e2c2;
}

.example {
	display: -webkit-box;
	display: -ms-flexbox;
	display: flex;
	-webkit-box-orient: vertical;
	-webkit-box-direction: normal;
	-ms-flex-direction: column;
	flex-direction: column;;
}