@keyframes gradientAnimation {
  0% {
    background-position: 0% 50%;
  }

  50% {
    background-position: 100% 50%;
  }

  100% {
    background-position: 0% 50%;
  }
}

html {
  height: 100%;
  background: linear-gradient(-45deg, #F2F5F8, #D6DFF5, #F2F5F8, #D6DFF5);
  background-size: 400% 400%;
  animation: gradientAnimation 15s ease infinite;
}

body {
  font-family: Arial, sans-serif;
  margin: 0;
  padding: 0;
}

.container {
  background-color: #FFFFFF;
  border-radius: 16px;
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.15);
  margin: 150px auto;
  padding: 40px;
  text-align: center;
  max-width: 400px;
}

h1 {
  color: #334455;
  margin-top: 0;
}

button {
  background: linear-gradient(to bottom right, #334455, #1C2E4A);
  border: none;
  border-radius: 24px;
  color: #FFFFFF;
  cursor: pointer;
  font-size: 16px;
  padding: 12px 24px;
  margin-top: 20px;
  text-shadow: 0 1px 1px rgba(0, 0, 0, 0.3);
  transition: all 0.2s ease;
}

button:hover {
  background: linear-gradient(to bottom right, #1C2E4A, #334455);
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
  transform: translateY(-2px);
}

#popup {
  background-color: #FFFFFF;
  border-radius: 16px;
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.15);
  margin-top: 20px;
  padding: 20px;
  text-align: center;
}

.hidden {
  display: none;
}

.footer {
  margin-top: 40px;
}

.footer a {
  color: #334455;
  margin: 0 10px;
  text-decoration: none;
}

.footer a:hover {
  color: #6688AA;
}