<div class="hashnode"></div>

body {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
}
.hashnode {
  width: 5em;
  height: 5em;
  border-radius: 1.25em;
  background: #2962ff;
  transform: rotate(45deg);
  display: grid;
  place-items: center;
  &:before {
    content: '';
    border-radius: 50%;
    background: white;
    height: 2em;
    width: 2em;
  }
}