.scroll-to-top-button {
   display: none;
   position: fixed;
   bottom: 20px;
   right: 30px;
   z-index: 99;
   border: none;
   outline: none;
   background-color: #000;
   color: white;
   cursor: pointer;
   padding: 4px;
   border-radius: 10px;
   font-size: 1em;
   width: 3em;
   height: 3em;
   animation: wiggle 300ms;
   transition: top 300ms ease-out,
               right 300ms ease-out,
               bottom 300ms ease-out,
               left 300ms ease-out;
}

.scroll-to-top-button:hover {
   background-color: #666;
   transition: background-color 400ms;
}