.refund-checker {
  width: 100%;
  max-width: 100%;
  box-sizing: border-box;
  background: #f9f9f9;
  padding: 1.5em;
  border: 1px solid #ddd;
  border-radius: 8px;
  margin: 1em 0;
}

.refund-checker form {
  display: flex;
  flex-direction: column;
  gap: 1em;
}

.refund-checker label {
  font-weight: bold;
}

.refund-checker input,
.refund-checker select,
.refund-checker button {
  padding: 0.5em;
  font-size: 1em;
  border-radius: 4px;
  border: 1px solid #ccc;
  width: 100%;
  box-sizing: border-box;
}

.refund-checker button {
  background-color: #0073aa;
  color: white;
  border: none;
  cursor: pointer;
  transition: background-color 0.3s;
}

.refund-checker button:hover {
  background-color: #005f8d;
}

.refund-result {
  margin-top: 1em;
  font-size: 1.1em;
}

@media (min-width: 768px) {
  .refund-checker {
    max-width: 600px;
    margin: 1em auto;
  }
}