<div class="divShape"></div>

.divShape {
  display: block;
  width: 500px;
  height: 500px;
  background: #222;
  filter: drop-shadow(3px 5px 2px rgb(0 0 0 / 0.4)); 
}

/* 見た目用 */
body {
  background: #666;
}

div, svg {
  display: block;
  margin: 0 auto;
}

p {
  color: white;
}