body {
  font-family: Arial, sans-serif;
  text-align: center;
  margin: 40px;
}

.drop-zone {
  border: 3px dashed #aaa;
  border-radius: 10px;
  padding: 40px;
  cursor: pointer;
  transition: 0.2s;
}

.drop-zone.active {
  border-color: #28a745;
  background: #f9fff9;
}

button {
  padding: 10px 20px;
  margin-top: 15px;
  cursor: pointer;
}