body {
  margin: 0;
  padding: 0;
  background-color: #333;
  font-family: Arial, sans-serif;
}

.overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.8);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.5s, visibility 0.5s;
}

.overlay.show {
  opacity: 1;
  visibility: visible;
}

.content {
  text-align: center;
  color: #fff;
}

h1 {
  font-size: 36px;
  margin-bottom: 20px;
}

p {
  font-size: 18px;
  margin-bottom: 20px;
}

.btn {
  display: inline-block;
  padding: 10px 20px;
  background-color: #fff;
  color: #333;
  text-decoration: none;
  border-radius: 4px;
  font-size: 16px;
  transition: background-color 0.3s;
}

.btn:hover {
  background-color: #f2f2f2;
}