.popup__wrapper {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100%;
  min-height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 1;
}

.popup {
  position: relative;
  margin: 10px;
  padding: 30px;
  text-align: center;
  color: #fff;
  background: linear-gradient(120deg, #3498db, #8e44ad, #3498db);
  background-size: 200%;
  transition: 0.5s;
}
.popup:hover {
  background-position: right;
}
.close {
  position: absolute;
  top: -5px;
  right: 5px;
  color: lightpink;
  font-size: 30px;
  font-weight: 900;
  cursor: pointer;
}
.close:hover {
  font-size: 40px;
  transition: 0.5s;
  animation: spin 1s linear;
}
@keyframes spin {
  100% {
    transform: rotate(360deg);
  }
}
.popup__title {
  font-size: 24px;
  text-transform: uppercase;
  animation-name: stretch;
  animation-duration: 2s;
  animation-timing-function: ease-in;
  animation-direction: alternate;
  animation-iteration-count: infinite;
  animation-play-state: running;
}
.win {
  font-size: 30px;
  font-weight: 900;
}

@keyframes stretch {
  0% {
    color: rgb(146, 231, 146);
  }

  50% {
    color: rgb(241, 194, 106);
  }

  100% {
    color: rgb(230, 124, 124);
  }
}

.btn-wrapper {
  margin: 10px;
  display: flex;
  justify-content: center;
  align-items: center;
}

.btn {
  position: relative;
  display: inline-block;
  margin: 10px;
  padding: 15px 30px;
  background-color: transparent;
  text-transform: uppercase;
  letter-spacing: 4px;
  text-decoration: none;
  font-size: 24px;
  overflow: hidden;
  transition: 0.5s;
  outline: none;
  border: none;
}

.again,
.correct {
  color: lightgreen;
}

.btn:hover {
  color: #fff;
  transition-delay: 1s;
}

.again:hover {
  background-color: lightgreen;
  box-shadow: 0 0 10px lightgreen, 0 0 40px lightgreen, 0 0 80px lightgreen;
}

.btn span {
  position: absolute;
  display: block;
}

.btn span:nth-child(1) {
  top: 0;
  left: -100%;
  width: 100%;
  height: 2px;
}
.again span:nth-child(1) {
  background: linear-gradient(90deg, transparent, lightgreen);
}
.btn:hover span:nth-child(1) {
  left: 100%;
  transition: 1s;
}

.btn span:nth-child(2) {
  top: -100%;
  right: 0;
  width: 2px;
  height: 100%;
}
.again span:nth-child(2) {
  background: linear-gradient(180deg, transparent, lightgreen);
}
.btn:hover span:nth-child(2) {
  top: 100%;
  transition: 1s;
  transition-delay: 0.25s;
}

.btn span:nth-child(3) {
  bottom: 0;
  right: -100%;
  width: 100%;
  height: 2px;
}
.again span:nth-child(3) {
  background: linear-gradient(270deg, transparent, lightgreen);
}
.btn:hover span:nth-child(3) {
  right: 100%;
  transition: 1s;
  transition-delay: 0.5s;
}

.btn span:nth-child(4) {
  bottom: -100%;
  left: 0;
  width: 2px;
  height: 100%;
}
.again span:nth-child(4) {
  background: linear-gradient(360deg, transparent, lightgreen);
}
.btn:hover span:nth-child(4) {
  bottom: 100%;
  transition: 1s;
  transition-delay: 0.75s;
}

.hidden {
  display: none;
}

@media (max-width: 768px) {
  .btn-wrapper {
    flex-wrap: wrap;
  }
}