.calculator {
  background: #fff;
  padding: 25px;
  border-radius: 15px;
  max-width: 480px;
  width: 100%;
  margin: 0 auto;
  border: 2px solid #ddd;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.05);
  display: flex;
  flex-direction: column;
  gap: 20px; /* spacing between children */
}

.hec-heading {
  margin-top: 0;
  font-size: 22px;
  padding-bottom: 6px;
  border-bottom: 2px solid #eee;
  margin-bottom: 20px;
  color: #222;
}

label {
  display: block;
  margin-bottom: 6px;
  color: #555;
  font-weight: 600;
}

select, input, button {
  width: 100%;
  padding: 10px;
  font-size: 16px;
  border: 1px solid #ccc;
  border-radius: 10px;
  margin-bottom: 10px;
}

button {
  background-color: #007bff;
  color: #fff;
  font-weight: bold;
  cursor: pointer;
  transition: background-color 0.3s ease;
}

button:hover {
  background-color: #0056b3;
}

.result {
  margin-top: 20px;
  font-size: 20px;
  text-align: center;
  font-weight: bold;
  color: #222;
}

.result .icon {
  font-size: 24px;
  color: #4db6ac;
  margin-right: 8px;
}