*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: #f4f6f9;
  color: #222;
  margin: 0;
  padding: 2rem 1rem;
  line-height: 1.5;
}

.container {
  max-width: 720px;
  margin: 0 auto;
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 2px 12px rgba(0, 0, 0, 0.08);
  padding: 2rem 2.5rem;
}

h1 {
  margin: 0 0 0.25rem;
  font-size: 1.6rem;
}

.subtitle {
  color: #555;
  margin: 0 0 1.5rem;
}

fieldset {
  border: 1px solid #ddd;
  border-radius: 6px;
  padding: 1rem 1.25rem;
  margin-bottom: 1.25rem;
}

legend {
  font-weight: 600;
  padding: 0 0.4rem;
  font-size: 0.95rem;
}

.checkbox-group label {
  display: block;
  margin-bottom: 0.4rem;
  cursor: pointer;
}

.checkbox-group input[type="checkbox"] {
  margin-right: 0.4rem;
}

.form-row {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.form-group {
  flex: 1;
  min-width: 160px;
  margin-bottom: 0.5rem;
}

.form-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: 0.3rem;
  color: #444;
}

input[type="number"],
select {
  width: 100%;
  padding: 0.45rem 0.6rem;
  border: 1px solid #ccc;
  border-radius: 4px;
  font-size: 0.95rem;
}

input[type="number"]:focus,
select:focus {
  outline: none;
  border-color: #4a90d9;
  box-shadow: 0 0 0 2px rgba(74, 144, 217, 0.2);
}

button[type="submit"] {
  display: block;
  width: 100%;
  padding: 0.7rem;
  font-size: 1rem;
  font-weight: 600;
  color: #fff;
  background: #2a6cb6;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background 0.15s;
}

button[type="submit"]:hover {
  background: #1d5595;
}

/* Results */
.results {
  margin-top: 2rem;
  border-top: 2px solid #e0e0e0;
  padding-top: 1.5rem;
}

.results h2 {
  margin: 0 0 1rem;
  font-size: 1.3rem;
}

.result-section {
  margin-bottom: 1.5rem;
}

.result-section h3 {
  font-size: 1rem;
  margin: 0 0 0.6rem;
  color: #2a6cb6;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 0.75rem;
}

th, td {
  text-align: left;
  padding: 0.45rem 0.6rem;
  border-bottom: 1px solid #e8e8e8;
}

th {
  background: #f7f9fc;
  font-size: 0.85rem;
  font-weight: 600;
  color: #555;
}

td {
  font-size: 0.95rem;
}

#cost-results p {
  margin: 0.35rem 0;
}

.highlight {
  font-weight: 600;
  color: #1a7a3a;
}

.highlight-warn {
  font-weight: 600;
  color: #b85c00;
}

.hidden {
  display: none;
}

#loading {
  text-align: center;
  padding: 1rem;
  color: #666;
  font-style: italic;
}

#error {
  color: #c0392b;
  background: #fdecea;
  padding: 0.75rem 1rem;
  border-radius: 4px;
  margin-top: 1rem;
}