Center a DIV and content horizontally and vertically

by Nivin NV

HTML

<div class="main1">
<div class="content">hello</div>
</div>

CSS

.main1 {
	width: 100%;
	height: 100%;	
	height: 100vh;
	background-color: #555;

	
	margin: auto;
	display: flex;
    justify-content: center;
    align-items: center;
    resize: both;
    padding-top: 0px !important;}

.content{ 
        background: #868686;
    width: 300px;
    height: 300px;
    
    	margin: auto;
	display: flex;
    justify-content: center;
    align-items: center;
    resize: both;
    padding-top: 0px !important;}