body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: #f7f9fc;
  margin: 0;
  padding: 20px;
  color: #222;
}

.container {
  max-width: 700px;
  margin: auto;
  background: #fff;
  padding: 2rem;
  border-radius: 14px;
  box-shadow: 0 0 15px rgba(0,0,0,0.08);
}

.title {
  text-align: center;
  font-size: 2.2rem;
  margin-bottom: 1.5rem;
  font-weight: 700;
  color: #003366;
}

.section {
  margin-bottom: 2rem;
}

h2 {
  font-size: 1.4rem;
  color: #00509e;
  margin-bottom: 0.75rem;
  border-bottom: 2px solid #007bff;
  padding-bottom: 5px;
}

.item-list {
  margin-bottom: 10px;
}

.item {
  display: flex;
  gap: 10px;
  margin-bottom: 10px;
}

input[type="text"], input[type="number"] {
  flex: 1;
  padding: 0.6rem;
  border: 1px solid #bbb;
  border-radius: 6px;
  font-size: 1rem;
}

.add-btn, .calculate-btn {
  background-color: #007bff;
  color: white;
  border: none;
  padding: 0.7rem 1.5rem;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 600;
  font-size: 1rem;
  transition: background-color 0.3s ease;
  display: inline-block;
}

.add-btn:hover, .calculate-btn:hover {
  background-color: #0056b3;
}

.results {
  margin-top: 2rem;
  background: #e9f7f9;
  padding: 1.5rem;
  border-radius: 10px;
  box-shadow: 0 0 10px rgba(0,123,255,0.2);
}

.warning {
  color: #d9534f;
  font-weight: bold;
  margin-top: 1rem;
}