body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  max-width: 1100px;
  margin: 2rem auto;
  padding: 0 1.5rem;
  color: #222;
  line-height: 1.5;
}

header h1 { margin-bottom: 0.25rem; }
.subtitle { margin-top: 0; }

section { margin: 2rem 0; }
section[hidden] { display: none; }

h2 {
  border-bottom: 1px solid #ddd;
  padding-bottom: 0.25rem;
  margin-bottom: 1rem;
}

section.collapsible h2 {
  cursor: pointer;
  user-select: none;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
}

section.collapsible h2::after {
  content: '▲';
  font-size: 0.7em;
  color: #aaa;
  margin-left: 0.5rem;
  flex-shrink: 0;
}

section.collapsible.collapsed h2 {
  border-bottom-color: transparent;
  margin-bottom: 0;
}

section.collapsible.collapsed h2::after {
  content: '▼';
}

section.collapsible.collapsed > *:not(h2) {
  display: none;
}

.scroll-x { overflow-x: auto; }

table {
  border-collapse: collapse;
  font-size: 0.9rem;
}

th, td {
  border: 1px solid #ddd;
  padding: 0.4rem 0.6rem;
  text-align: left;
  white-space: nowrap;
}

th { background: #f6f6f6; }

#column-controls {
  max-width: 560px;
}

.col-row {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.35rem 0;
  border-bottom: 1px solid #f0f0f0;
}

.col-row label {
  flex: 1;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.9rem;
}

.col-row select {
  min-width: 180px;
  padding: 0.3rem;
}

input[type="file"] {
  padding: 0.5rem;
  border: 1px dashed #aaa;
  border-radius: 4px;
  background: #fafafa;
}

.actions {
  margin-top: 1rem;
}

button {
  font: inherit;
  padding: 0.5rem 1rem;
  background: #2563eb;
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
}

button:hover { background: #1d4ed8; }

.cleaning-card {
  border: 1px solid #ddd;
  border-radius: 4px;
  padding: 1rem;
  margin-bottom: 1.5rem;
  background: #fff;
}

.cleaning-card .card-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 0.75rem;
}

.cleaning-card h3 {
  margin: 0;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 1rem;
}

.card-controls {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.card-controls select {
  padding: 0.25rem;
  margin-left: 0.25rem;
}

.map-status {
  color: #666;
  font-size: 0.9rem;
}

.mapping-table {
  width: 100%;
  font-size: 0.9rem;
}

.mapping-table .num {
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.mapping-table .map-input {
  width: 70px;
  padding: 0.2rem 0.3rem;
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
}

.mapping-table tr.unmapped td {
  background: #fff4f4;
}

.mapping-table tr.unmapped .map-input {
  border: 1px solid #d33;
}

.comparison-controls {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  max-width: 560px;
}

.block-label {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  font-size: 0.95rem;
}

.block-label select,
.block-label input[type="number"] {
  padding: 0.3rem;
  font: inherit;
}

.hint {
  color: #666;
  font-size: 0.85rem;
  margin: 0.25rem 0 0;
}

.hint-inline {
  color: #666;
  font-size: 0.85rem;
  font-weight: normal;
}

.warning {
  color: #b00;
  font-size: 0.9rem;
  margin: 0.25rem 0 0;
}

.num {
  text-align: right;
  font-variant-numeric: tabular-nums;
}

#results table {
  margin-top: 0.5rem;
}

#results h3 {
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
  font-size: 1rem;
}

.num.sig {
  color: #067a3d;
  font-weight: 600;
}

.num.n-small {
  color: #b87f00;
  font-weight: 600;
}

.num.n-tiny {
  color: #c0392b;
  font-weight: 700;
}

.warning-banner {
  background: #fff8e1;
  border-left: 4px solid #f59e0b;
  padding: 0.6rem 1rem;
  margin: 0 0 1rem;
  border-radius: 2px;
  font-size: 0.92rem;
}

.warning-banner p {
  margin: 0;
}

.warning-banner p + p {
  margin-top: 0.4rem;
}

.interpretation-panel {
  background: #f0f9ff;
  border-left: 4px solid #2563eb;
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  border-radius: 2px;
}

.interpretation-panel h3 {
  margin: 0 0 0.5rem;
  font-size: 1rem;
  color: #1e40af;
}

.interpretation-panel p {
  margin: 0.5rem 0;
  line-height: 1.55;
}

.interpretation-panel p.callout {
  background: #fef3c7;
  border-left: 3px solid #f59e0b;
  padding: 0.6rem 0.85rem;
  margin-top: 0.75rem;
  font-size: 0.92rem;
  border-radius: 2px;
}

.interpretation-panel p.callout em {
  font-style: italic;
}

.prompt-row {
  margin-top: 1rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.copy-prompt {
  font-size: 0.85rem;
  padding: 0.4rem 0.8rem;
  background: #475569;
}

.copy-prompt:hover {
  background: #334155;
}

.prompt-row .hint {
  margin: 0;
}

#loading-overlay {
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  background: rgba(20, 20, 20, 0.92);
  color: white;
  padding: 1rem 1.5rem;
  border-radius: 6px;
  z-index: 1000;
  max-width: 420px;
  text-align: center;
  font-size: 0.95rem;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

#loading-overlay[hidden] {
  display: none;
}

button:disabled {
  background: #94a3b8;
  cursor: not-allowed;
}

.chart-block {
  margin-top: 1.5rem;
}

.chart-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.5rem;
}

.chart-header h3 {
  margin: 0;
}

.export-png {
  padding: 0.3rem 0.7rem;
  font-size: 0.85rem;
  background: #475569;
}

.export-png:hover {
  background: #334155;
}

.chart {
  width: 100%;
  height: 420px;
  border: 1px solid #eee;
  border-radius: 4px;
  background: #fff;
}

/* Small-sample dialog */
#small-sample-dialog {
  border: 1px solid #ddd;
  border-radius: 8px;
  padding: 1.5rem;
  max-width: 480px;
  width: 90vw;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.18);
}

#small-sample-dialog::backdrop {
  background: rgba(0, 0, 0, 0.45);
}

#small-sample-dialog h3 {
  margin: 0 0 0.75rem;
  font-size: 1.05rem;
  color: #92400e;
}

#ssd-list {
  margin: 0.25rem 0 0.75rem 1.25rem;
  padding: 0;
  font-size: 0.92rem;
}

#ssd-list li {
  margin-bottom: 0.2rem;
}

.ssd-note {
  font-size: 0.88rem;
  color: #555;
  margin: 0 0 1.25rem;
}

.dialog-actions {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
  align-items: center;
}

.btn-secondary {
  background: #64748b;
}

.btn-secondary:hover {
  background: #475569;
}

.btn-ghost {
  background: transparent;
  color: #555;
  border: 1px solid #ccc;
  padding: 0.45rem 0.9rem;
}

.btn-ghost:hover {
  background: #f1f5f9;
  color: #222;
}

/* ============================================================
   Scale guide (collapsible reference in step 4)
   ============================================================ */

.scale-guide {
  font: inherit;
  margin: 0.75rem 0 1.25rem;
  max-width: 1100px;
}

.scale-guide summary {
  cursor: pointer;
  font-size: 0.88rem;
  color: #2563eb;
  user-select: none;
  list-style: none;
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
}

.scale-guide summary::-webkit-details-marker { display: none; }

.scale-guide summary::before {
  content: '▶';
  font-size: 0.65em;
  transition: transform 0.15s;
}

.scale-guide[open] summary::before {
  transform: rotate(90deg);
}

.scale-guide-body {
  font: inherit;
  margin-top: 1rem;
  max-width: 680px;
}

.scale-section {
  padding: 0.75rem 0;
}

.scale-section-title {
  margin: 0 0 0.15rem;
  font-size: 1rem;
}

.scale-guide .scale-diagram {
  display: block;
  margin: 0.5rem 0 0.25rem;
}

/* Labels aligned under the SVG circles (x=80 to x=620 in a 680-wide viewBox) */
.scale-point-labels {
  display: flex;
  justify-content: space-between;
  padding: 0 8.8% 0 11.8%;
  font-size: 0.82rem;
  color: #666;
}

.scale-point-labels--three {
  padding: 0 8% 0 10%;
}

.scale-direction-label {
  text-align: center;
  margin: 0.2rem 0 0;
}

.scale-direction-row {
  display: flex;
  justify-content: space-between;
  padding: 0.2rem 18% 0;
  font-size: 0.85rem;
}

.scale-section-divider {
  border: none;
  border-top: 1px dashed #ddd;
  margin: 0.25rem 0;
}

/* ============================================================
   Scale diagram styles
   ============================================================ */

.scale-diagram {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  --diagram-text-primary:   #222;
  --diagram-text-secondary: #666;
  --diagram-border:         rgba(0, 0, 0, 0.15);

  --diagram-teal-50:   #e1f5ee;
  --diagram-teal-400:  #1d9e75;
  --diagram-teal-600:  #0f6e56;
  --diagram-teal-800:  #085041;

  --diagram-coral-50:  #faece7;
  --diagram-coral-400: #d85a30;
  --diagram-coral-600: #993c1d;
  --diagram-coral-800: #712b13;

  --diagram-gray-50:   #f1efe8;
  --diagram-gray-400:  #888780;
  --diagram-gray-600:  #5f5e5a;
}

@media (prefers-color-scheme: dark) {
  .scale-diagram {
    --diagram-text-primary:   #e0e0e0;
    --diagram-text-secondary: #999;
    --diagram-border:         rgba(255, 255, 255, 0.15);
  }
}

.scale-diagram .sd-num {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  font-size: 13px;
  font-weight: 600;
  fill: var(--diagram-text-primary);
}

.scale-diagram .c-teal  > circle,
.scale-diagram .c-teal  > rect {
  fill:   var(--diagram-teal-400);
  stroke: var(--diagram-teal-600);
}

.scale-diagram .c-coral > circle,
.scale-diagram .c-coral > rect {
  fill:   var(--diagram-coral-400);
  stroke: var(--diagram-coral-600);
}

.scale-diagram .c-gray  > circle,
.scale-diagram .c-gray  > rect {
  fill:   var(--diagram-gray-50);
  stroke: var(--diagram-gray-600);
}


.scale-diagram .arrow-teal {
  stroke: var(--diagram-teal-600);
  stroke-width: 1;
  fill: none;
}

.scale-diagram .arrow-neutral {
  stroke: var(--diagram-gray-600);
  stroke-width: 1;
  fill: none;
}

.scale-diagram .divider {
  stroke: var(--diagram-border);
  stroke-width: 0.5;
  stroke-dasharray: 4 4;
}