<div class="spinner" aria-label="loading..."></div>

@keyframes spin {
  from {
    transform: rotate(0);
  }
  
  to {
    transform: rotate(360deg);
  }
}

.spinner {
  animation: spin 1s linear infinite;
}

/* page styles */
*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  display: grid;
  place-items: center;
  height: 100vh;
}

.spinner {
  width: 5rem;
  height: 5rem;
  border: 0.3rem solid limegreen;
  border-top-color: transparent;
  border-radius: 999rem;
}