body {
  text-align: center;
  position: relative;
}

@keyframes rotate {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

.modal {
  display: none;
  position: fixed;
  z-index: 1;
  background-color: #fff;
  left: 0;
  right: 0;
  top: 147px;
  width: 404px;
  height: 300px;
  margin: 0 auto;
  align-items: center;
  flex-direction: column;
}
.visible {
  display: flex;
}

.checkmark {
  margin-top: 20px;
  width: 50px;
  height: 50px;
  padding: 4px;
  border: solid 3px lightgrey;
  border-radius: 50%;
  opacity: 0.5;
  animation-duration: 3s; /*here and below: keyframes are declared in index.html in the <head>*/
}

.modal-header {
  font-size: 24px;
  font-weight: 700;
  color: #4a4a4a;
  letter-spacing: -1px;
  animation-delay: 1s;
}

 .modal-exclamation {
  font-size: 18px;
  letter-spacing: -1px;
  color: #4a4a4a;
  animation-delay: 2s;
}

.modal-play-again {
  margin-top: 50px;
  width: 180px;
  height: 30px;
  background-color: #02ccba;
  color: #fff;
  text-align: center;
  padding: 8px 0;
  font-size: 22px;
  font-weight: bold;
  border-radius: 6px;
  box-shadow: 3px 3px 5px 0px rgba(0,0,0,0.25);
  animation-delay: 3s;
  float: right;
  cursor: pointer;
}