:root {
  --bg: #f6f7f9;
  --card-bg: #ffffff;
  --border: #e2e5ea;
  --text: #1a1d23;
  --text-muted: #5b6270;
  --accent: #2563eb;
  --radius: 10px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.45;
}

.page-header {
  padding: 28px 24px 16px;
  max-width: 1080px;
  margin: 0 auto;
}

.page-header h1 {
  margin: 0 0 4px;
  font-size: 1.6rem;
}

.subtitle {
  margin: 0;
  color: var(--text-muted);
}

main {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px 48px;
}

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 24px;
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
  margin-bottom: 20px;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.control-label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
}

.pill-group {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.pill {
  border: 1px solid var(--border);
  background: #fff;
  border-radius: 999px;
  padding: 6px 14px;
  font-size: 0.88rem;
  cursor: pointer;
  user-select: none;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
}

.pill[aria-pressed="true"] {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.pill.grade-pill[aria-pressed="true"] {
  color: #fff;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px 24px 24px;
  margin-bottom: 20px;
}

.card h2 {
  margin: 0 0 4px;
  font-size: 1.1rem;
}

.card-hint {
  margin: 0 0 16px;
  color: var(--text-muted);
  font-size: 0.88rem;
  max-width: 70ch;
}

.table-wrap,
.chart-scroll {
  overflow-x: auto;
}

table {
  border-collapse: collapse;
  width: 100%;
  font-size: 0.88rem;
}

th, td {
  padding: 6px 10px;
  border-bottom: 1px solid var(--border);
  text-align: right;
  white-space: nowrap;
}

th:first-child, td:first-child {
  text-align: left;
}

thead th {
  color: var(--text-muted);
  font-weight: 600;
  border-bottom: 2px solid var(--border);
}

tbody tr:hover {
  background: #fafbfc;
}

.grade-row-header td {
  font-weight: 700;
  background: #f9fafb;
}

.page-footer {
  color: var(--text-muted);
  font-size: 0.8rem;
  margin-top: 8px;
}

svg text {
  font-family: inherit;
  fill: var(--text);
}

.band-bar-bg {
  fill: #eef1f5;
}

.overlap-region {
  fill: #fde68a;
  opacity: 0.55;
}

.axis-line {
  stroke: var(--border);
  stroke-width: 1;
}

.grid-line {
  stroke: var(--border);
  stroke-width: 1;
  stroke-dasharray: 2 3;
}

.effective-date-note {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.chart-tooltip {
  position: fixed;
  pointer-events: none;
  background: #1a1d23;
  color: #fff;
  padding: 8px 12px;
  border-radius: 6px;
  font-size: 0.8rem;
  line-height: 1.4;
  z-index: 1000;
  max-width: 260px;
  max-height: 70vh;
  overflow-y: auto;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
}

.tooltip-steps {
  display: grid;
  grid-template-columns: auto auto;
  column-gap: 14px;
  row-gap: 2px;
  margin-top: 6px;
  font-variant-numeric: tabular-nums;
}

.tooltip-steps span:nth-child(odd) {
  color: #cbd5e1;
}

.tooltip-steps span:nth-child(even) {
  text-align: right;
  font-weight: 600;
}

.chart-tooltip[hidden] {
  display: none;
}

.chart-hit {
  cursor: pointer;
}

.calculator {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  align-items: flex-end;
}

.calc-field {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.calc-field select,
.calc-field input {
  font-family: inherit;
  font-size: 1rem;
  padding: 8px 10px;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: #fff;
  color: var(--text);
  min-width: 140px;
}

.calc-result {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 10px 18px;
  border-radius: 8px;
  background: #eff6ff;
  border: 1px solid #bfdbfe;
}

.calc-result .calc-amount {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent);
}

.calc-result .calc-label {
  font-size: 0.78rem;
  color: var(--text-muted);
}

@media (max-width: 640px) {
  .page-header { padding: 20px 16px 12px; }
  main { padding: 0 16px 40px; }
  .card { padding: 16px 16px 18px; }
  .pill { padding: 6px 11px; font-size: 0.82rem; }
  .calculator { flex-direction: column; align-items: stretch; }
  .calc-field select, .calc-field input { min-width: 0; width: 100%; }
  .calc-result { align-items: flex-start; }
  table { font-size: 0.8rem; }
  th, td { padding: 5px 6px; }
}