Atractivo y sencillo spinner HTML/CSS para nuestros proyectos web

<style>
    * {
        margin: 0;
        padding: 0;
      }
      
      .loader {
        display: none;
        top: 50%;
        left: 50%;
        position: absolute;
        transform: translate(-50%, -50%);
      }
      
      .loading {
        width: 150px;
        height: 150px;
        margin: -75px 0 0 -75px;
        border: 16px solid #f3f3f3;
        border-radius: 50%;
        border-top: 16px solid #3498db;
        width: 120px;
        height: 120px;
        -webkit-animation: spin 2s linear infinite;
        animation: spin 2s linear infinite;
      }
      
      @keyframes spin {
        0% {
          transform: rotate(0deg);
        }
      
        100% {
          transform: rotate(360deg);
        }
      }
</style>

<button type="submit" class="sbtn btn btn-secondary btn-c" onclick="spinner()">Log in</button>
<div class="loader">
  <div class="loading">
  </div>
</div>

        <script type="text/javascript">
            function spinner() {
                document.getElementsByClassName("loader")[0].style.display = "block";
            }
        </script>