/* Body with sky-to-snow gradient */
body {
  font-family: Arial, sans-serif;
  text-align: center;
  background: linear-gradient(to bottom, #87ceeb, #ffffff);
  margin: 0;
  height: 100vh;
  overflow: hidden;
}

h1 {
  margin-top: 20px;
}

/* Popup overlay */
#popup {
  position: fixed;
  top:0; left:0; right:0; bottom:0;
  display:flex;
  justify-content:center;
  align-items:center;
  background: rgba(0, 0, 0, 0.7);
}

.popup-content {
  background: #f9f9f9;
  padding: 20px;
  border-radius: 15px;
  box-shadow: 0 0 20px rgba(0,0,0,0.5);
  border: 3px solid #0077ff;
  display: flex;
  flex-direction: column;
  align-items: center;
}

/* Close button */
#close-btn {
  background: #ff4b4b;
  color: white;
  border: none;
  padding: 8px 12px;
  border-radius: 8px;
  font-size: 14px;
  cursor: pointer;
  margin-top: 10px;
  transition: 0.2s;
}

#close-btn:hover {
  background: #ff0000;
}