<div class="tanjiro">
  <h1>竈門炭治郎</h1>
</div>

body {
    margin: 0;
}
body > div {
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: -1;
}
.tanjiro {
	background: 
	linear-gradient(45deg, #3cc 25%, transparent 25%, transparent 75%, #3cc 75%) 0 0 / 60px 60px,
	linear-gradient(45deg, #3cc 25%, transparent 25%, transparent 75%, #3cc 75%) 30px 30px / 60px 60px,
	#222;
}
h1 {
	background: #fff;
	padding: .5em 1em;
  border-radius: .5em;
}