#added-to-cart {
  position: fixed;
  /** will always stay in place even when the page scrolls */
  
  width: 50%;
  /** give it a width so the element doesn't take 100% of the viewport (you may alternatively "col-*" classes to it to maintain responsiveness) */

  right: 0;
  left: 0;
  margin: auto;
  /** 
  * the above 3 rules center the element horizontally.
  * the "right" and "left" rules must have a value of "0" or else the element cannot be centered using the "margin" rule;
  */
  
  /*
top: 50%;
  transform: translate3d(0, -50%, 0);
*/
  /** the above 2 rules center the elemnt vertically */
  
  top:0;
  /* Horizontally center at top only */

  text-align: center;
  z-index: 9999;
  
  border:3px white solid;
  border-radius:15px;
}

/** just to visually showcase the demo */
/* height: 300vh; /** to simulate a long page 
body {
  height: 300vh; 
  background-image: linear-gradient(to bottom, #afafaf, #fafafa)!important;
}
*/
/** "!important" is not required but since SO applies a background rule to the body elemnt on snippets we must override it */