.hidden {
  display: none;
}
.popup {
  z-index: 289; 
  position: fixed; 
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  display: flex;
  flex-direction:column; 
  justify-content: center; /* center horizontally */
  align-items: center;     /* center vertically */
  height: 100vh;           /* full viewport height */
  margin: 0;               /* remove default margin */
}

a:hover {
 color: pink; 
}

.popupContent {
  border: 2px solid #a1b2d7;
  background-color: #d7deee;
  border-radius: 8px; 
  padding: 60px;
  width: 500px;
  text-align: center; 
  position: relative; 
}

#closeWindowButton {
  width: 30px; 
  position: absolute; 
  top: 7px; 
  right: 7px;
}