* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #f4f6f8;
  color: #222;
}

.success-box {
  padding: 15px;
  background: #e9f8ee;
  border: 1px solid #34a853;
  border-radius: 10px;
}

.error-box {
  padding: 15px;
  background: #fdeaea;
  border: 1px solid #d93025;
  color: #b00020;
  border-radius: 10px;
  font-weight: 600;
}

button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}