Nice CSS only spinner "Waitig for page load"

layout:

<div class="overlay" style="display: none;">
    <div class="spinner" id="spinner"></div>
</div>

<script>

 // Spinner
  document.addEventListener("DOMContentLoaded", function () {
      const elements = document.querySelector(".big_button");
      // Too many false positives?
      //const elements = document.querySelector("a, input[type=submit]");
      const overlay = document.querySelector(".overlay");

      if (elements) {
          elements.addEventListener("click", function () {

              // event.preventDefault();
              // event.stopImmediatePropagation();

              setTimeout(function () {
                  overlay.style.display = "flex";
              }, 750);

          });
      }
  });

</script>

css:

/* Spinner */
.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.3);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 9999;
}

.spinner {
    border: 10px solid white;
    border-top: 10px solid #ef7f01;
    border-radius: 50%;
    width: 50px;
    height: 50px;
    animation: spin 1.5s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}