:root {
  /* Strictly monochrome: white/gray/black only, no hue anywhere. Severity
     (ok/caution/warning) is conveyed by border weight, fill opacity, and
     an explicit text label/symbol -- never by color alone. */
  --bg: #000000;
  --card-bg: transparent;
  --text: #f0f0f0;
  --text-heading: #ffffff;
  --text-muted: #a8a8a8;
  --text-dim: #767676;
  --border: rgba(255, 255, 255, 0.14);
  --border-strong: rgba(255, 255, 255, 0.32);
  --accent: #ffffff;
  --accent-contrast: #000000;
  --grid-color: rgba(255, 255, 255, 0.09);
  --series-measured: #ffffff;
  --series-fit: #a8a8a8;
  --flag-ok-bg: rgba(255, 255, 255, 0.03);
  --flag-ok-border: rgba(255, 255, 255, 0.18);
  --flag-ok-text: #ffffff;
  --flag-warn-bg: rgba(255, 255, 255, 0.05);
  --flag-warn-border: rgba(255, 255, 255, 0.4);
  --flag-warn-text: #ffffff;
  --flag-bad-bg: rgba(255, 255, 255, 0.09);
  --flag-bad-border: rgba(255, 255, 255, 0.85);
  --flag-bad-text: #ffffff;
  --max-width: 1080px;
  font-family: -apple-system, "Segoe UI", "Helvetica Neue", Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

.page-shell {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.app-header {
  padding: 48px 0 28px;
}
.app-header h1 {
  margin: 0 0 14px;
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -0.01em;
  color: var(--text-heading);
}
.subtitle {
  margin: 0;
  color: var(--text-muted);
  font-size: 0.98rem;
  line-height: 1.6;
}

.tabs {
  display: flex;
  gap: 4px;
  margin-bottom: 28px;
  border-bottom: 1px solid var(--border);
}
.tab-btn {
  padding: 11px 4px;
  margin-right: 28px;
  border: none;
  background: transparent;
  cursor: pointer;
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-dim);
  border-bottom: 2px solid transparent;
  transition: color 0.15s ease, border-color 0.15s ease;
}
.tab-btn:hover { color: var(--text-muted); }
.tab-btn.active {
  color: var(--text-heading);
  border-bottom-color: var(--accent);
}

main { padding-bottom: 56px; }

.layout-2col {
  display: grid;
  grid-template-columns: minmax(280px, 380px) 1fr;
  gap: 20px;
  align-items: start;
}
@media (max-width: 860px) {
  .layout-2col { grid-template-columns: 1fr; }
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 24px 26px;
  margin-bottom: 20px;
}
.card h2 {
  margin: 0 0 18px;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-heading);
}

.slider-row {
  display: grid;
  grid-template-columns: 1fr auto;
  grid-template-areas: "label value" "caption caption" "grounding grounding" "track track";
  align-items: center;
  column-gap: 10px;
  margin-bottom: 20px;
  font-size: 0.9rem;
}
.slider-row label {
  grid-area: label;
  color: var(--text-muted);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.slider-row output {
  grid-area: value;
  text-align: right;
  font-variant-numeric: tabular-nums;
  font-size: 0.82rem;
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 3px 9px;
  min-width: 64px;
  background: rgba(255, 255, 255, 0.02);
}
.slider-row input[type="range"] { grid-area: track; }
.unit { font-weight: 400; color: var(--text-dim); font-size: 0.85em; text-transform: none; letter-spacing: normal; }

/* --- range slider --- */
input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 20px;
  background: transparent;
  cursor: pointer;
  margin: 4px 0;
}
input[type="range"]::-webkit-slider-runnable-track {
  height: 2px;
  background: var(--border-strong);
  border-radius: 2px;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 15px;
  height: 15px;
  margin-top: -6.5px;
  border-radius: 50%;
  background: var(--text-heading);
  border: 2px solid #000;
  box-shadow: 0 0 0 1px var(--border-strong);
}
input[type="range"]::-moz-range-track {
  height: 2px;
  background: var(--border-strong);
  border-radius: 2px;
}
input[type="range"]::-moz-range-thumb {
  width: 13px;
  height: 13px;
  border-radius: 50%;
  background: var(--text-heading);
  border: 2px solid #000;
  box-shadow: 0 0 0 1px var(--border-strong);
}

.preset-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
  margin: 20px 0 4px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
}
.preset-label {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-dim);
  width: 100%;
  margin-bottom: 4px;
}
.preset-btn, .primary-btn {
  border: 1px solid var(--border);
  background: transparent;
  color: var(--text-muted);
  border-radius: 6px;
  padding: 8px 14px;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  transition: border-color 0.15s ease, color 0.15s ease;
}
.preset-btn:hover, .primary-btn:hover { border-color: var(--accent); color: var(--accent); }
.primary-btn {
  background: var(--accent);
  color: var(--accent-contrast);
  border-color: var(--accent);
  font-size: 0.85rem;
  font-weight: 700;
  padding: 10px 18px;
  margin-top: 12px;
}
.primary-btn:hover { background: #d8d8d8; border-color: #d8d8d8; color: var(--accent-contrast); }
.primary-btn:disabled { opacity: 0.35; cursor: not-allowed; }

.noise-controls {
  margin-top: 20px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  font-size: 0.85rem;
  color: var(--text-muted);
}
.noise-controls > label { display: flex; align-items: center; gap: 8px; cursor: pointer; }
.noise-controls input[type="checkbox"] { accent-color: var(--accent); width: 15px; height: 15px; }

textarea#csv-text {
  width: 100%;
  font-family: ui-monospace, "SF Mono", Consolas, monospace;
  font-size: 0.8rem;
  background: rgba(255, 255, 255, 0.02);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 10px;
  resize: vertical;
}
textarea#csv-text::placeholder { color: var(--text-dim); }
input[type="file"] {
  margin-top: 10px;
  color: var(--text-muted);
  font-size: 0.82rem;
}

.unit-selectors {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin: 18px 0;
}
.field {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-dim);
}
.field select {
  padding: 7px 8px;
  border-radius: 6px;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.02);
  color: var(--text);
  font-size: 0.85rem;
  font-weight: 400;
  text-transform: none;
  letter-spacing: normal;
}

.hint { font-size: 0.8rem; color: var(--text-dim); margin: 0 0 10px; font-style: italic; }

/* Plain-language explanation captions -- under slider labels, form
   fields, card headings, etc. Not italic (italic is reserved for .hint's
   more technical/incidental notes) so these read as the primary
   explanation, not an aside. */
.explain {
  font-size: 0.78rem;
  color: var(--text-dim);
  margin: 0 0 14px;
  line-height: 1.45;
}
.card h2 + .explain { margin-top: -10px; }
.slider-row .explain { grid-area: caption; margin: 2px 0 6px; max-width: none; }
.field .explain { font-size: 0.7rem; font-weight: 400; text-transform: none; letter-spacing: normal; margin: 2px 0 0; color: var(--text-dim); }

/* Range grounding / in-text citations under a slider's plain-language
   explanation -- deliberately smaller and dimmer than .explain, since
   it's a supporting footnote, not the primary caption. */
.slider-row .grounding { grid-area: grounding; margin: -4px 0 8px; }
.grounding {
  font-size: 0.7rem;
  color: var(--text-dim);
  line-height: 1.45;
  margin: 0 0 10px;
}
.citation-link {
  color: var(--text-muted);
  text-decoration: none;
  border-bottom: 1px dotted var(--border-strong);
}
.citation-link:hover, .citation-link:focus { color: var(--accent); border-bottom-color: var(--accent); }

.references-card ol.ref-list {
  margin: 0;
  padding-left: 22px;
  font-size: 0.8rem;
  color: var(--text-muted);
  line-height: 1.6;
}
.references-card ol.ref-list li { margin-bottom: 12px; }
.references-card ol.ref-list li:target { color: var(--text-heading); }
.references-card code {
  font-family: ui-monospace, "SF Mono", Consolas, monospace;
  font-size: 0.92em;
  color: var(--text);
}
.references-card a { color: var(--text-muted); text-decoration: underline; }
.references-card a:hover, .references-card a:focus { color: var(--accent); }

table.data-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.83rem;
  margin: 12px 0;
}
table.data-table th, table.data-table td {
  border: 1px solid var(--border);
  padding: 7px 10px;
  text-align: right;
  color: var(--text);
}
table.data-table th:first-child, table.data-table td:first-child { text-align: left; }
table.data-table th {
  background: rgba(255, 255, 255, 0.03);
  font-weight: 700;
  font-size: 0.72rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.result-row-flag { font-size: 0.78em; color: var(--text-dim); font-style: italic; }

.flag-box {
  border-radius: 6px;
  padding: 12px 14px;
  margin: 10px 0;
  font-size: 0.86rem;
  border: 1px solid;
  color: var(--text-muted);
  line-height: 1.5;
}
/* Severity is conveyed by border weight + fill opacity + an explicit
   text label/symbol in the markup -- deliberately not by color, since
   this page never uses color at all. */
.flag-ok { background: var(--flag-ok-bg); border-color: var(--flag-ok-border); border-width: 1px; }
.flag-ok strong { color: var(--flag-ok-text); }
.flag-warn { background: var(--flag-warn-bg); border-color: var(--flag-warn-border); border-width: 1px; }
.flag-warn strong { color: var(--flag-warn-text); }
.flag-bad {
  background: var(--flag-bad-bg);
  border-color: var(--flag-bad-border);
  border-width: 2px;
  font-weight: 500;
}
.flag-bad strong { color: var(--flag-bad-text); }
.flag-box strong {
  display: block;
  margin-bottom: 4px;
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.legend {
  display: flex;
  gap: 20px;
  font-size: 0.78rem;
  color: var(--text-dim);
  margin: 0 0 10px;
}
.legend span { display: inline-flex; align-items: center; }
.legend span::before {
  content: "";
  display: inline-block;
  margin-right: 7px;
  vertical-align: middle;
}
/* Dot vs. dashed line -- the same shape distinction used in the actual
   plots -- so the legend never has to rely on color. */
.legend .legend-measured::before {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--series-measured);
}
.legend .legend-fit::before {
  width: 18px;
  height: 0;
  border-top: 2px dashed var(--series-fit);
}

.axis-label { font-size: 9px; fill: var(--text-dim); }
.axis-title { font-size: 10px; fill: var(--text-muted); font-weight: 600; }

.plot-card svg { display: block; width: 100%; height: auto; }

.app-footer {
  padding: 24px 0 48px;
  color: var(--text-dim);
  font-size: 0.8rem;
  border-top: 1px solid var(--border);
  line-height: 1.6;
}
#model-status { font-weight: 700; color: var(--text-muted); }