/* ---------------------------------------------------------------- base */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; background: var(--ground); scrollbar-color: var(--control) var(--ground); }
body {
  margin: 0; min-height: 100dvh; background: var(--ground); color: var(--text);
  font: 400 var(--fs-body)/1.45 var(--font); -webkit-font-smoothing: antialiased;
}
img { display: block; max-width: 100%; }
button, input, select { font: inherit; color: inherit; }
button { cursor: pointer; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 4px; }
::selection { background: var(--accent); color: #fff; }
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-thumb { background: var(--control); border-radius: 999px; border: 2px solid var(--ground); }
::-webkit-scrollbar-track { background: transparent; }
.num { font-family: var(--mono); font-variant-numeric: tabular-nums; font-feature-settings: "tnum"; }
.muted { color: var(--muted); }
.secondary { color: var(--secondary); }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
h1, h2, h3, p { margin: 0; }
h1 { font-size: var(--fs-title); font-weight: 600; letter-spacing: -0.01em; line-height: 1.25; text-wrap: balance; }
h2 { font-size: var(--fs-section); font-weight: 600; line-height: 1.3; }
h3 { font-size: var(--fs-body); font-weight: 600; }
.small { font-size: var(--fs-small); }
a { color: var(--text); text-underline-offset: 3px; text-decoration-color: var(--control); }
a:hover { text-decoration-color: var(--text); }

/* ---------------------------------------------------------------- top bar */
.topbar {
  position: sticky; top: 0; z-index: 20; height: var(--topbar);
  display: flex; align-items: center; gap: var(--s6); padding: 0 var(--pad);
  background: var(--ground); border-bottom: 1px solid var(--border);
}
.brand { display: flex; align-items: center; gap: 10px; min-width: 0; }
.brand-name { font-weight: 600; font-size: 16px; white-space: nowrap; }
.brand-sub { color: var(--muted); font-size: var(--fs-small); white-space: nowrap; }
.tabs { display: flex; gap: var(--s6); height: 100%; }
.tab {
  position: relative; height: 100%; padding: 0; border: 0; background: none;
  color: var(--muted); font-weight: 500; transition: color var(--dur-fast) var(--ease-out);
}
.tab:hover { color: var(--secondary); }
.tab[aria-selected="true"] { color: var(--text); }
.tab[aria-selected="true"]::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -1px; height: 1px; background: var(--accent);
}
.topbar-end { margin-left: auto; display: flex; align-items: center; gap: var(--s3); min-width: 0; }

/* ---------------------------------------------------------------- pills */
.pill {
  display: inline-flex; align-items: center; gap: 6px; height: 24px; padding: 0 10px;
  border-radius: var(--radius-control); font-size: var(--fs-small); font-weight: 500; white-space: nowrap;
  background: var(--pill-neutral-bg); color: var(--pill-neutral-ink); max-width: 100%; overflow: hidden; text-overflow: ellipsis;
}
.pill.warning { background: var(--pill-warning-bg); color: var(--pill-warning-ink); }
.pill.positive { background: var(--pill-positive-bg); color: var(--pill-positive-ink); }
.pill.negative { background: var(--pill-negative-bg); color: var(--pill-negative-ink); }
.dot { width: 6px; height: 6px; border-radius: 50%; background: currentColor; flex: none; }

/* ---------------------------------------------------------------- buttons and controls */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: var(--control-height); padding: 0 16px; border-radius: var(--radius-control);
  border: 1px solid var(--control); background: transparent; color: var(--text); font-weight: 500; white-space: nowrap;
  transition: background-color var(--dur-fast) var(--ease-out), transform var(--dur-fast) var(--ease-out);
}
.btn:hover { background: var(--raised); }
.btn:active { transform: scale(0.97); }
.btn.primary { background: #fff; color: #111; border-color: #fff; }
.btn.primary:hover { background: #e8e8ea; }
.btn.text { border: 0; padding: 0 4px; height: auto; color: var(--secondary); text-decoration: underline; text-underline-offset: 3px; text-decoration-color: var(--control); }
.btn.text:hover { background: none; color: var(--text); }
.btn.icon { width: var(--control-height); padding: 0; }
.btn:disabled { opacity: 0.45; cursor: default; transform: none; }

.seg { display: flex; flex-wrap: wrap; column-gap: var(--s4); row-gap: 2px; }
.seg button {
  position: relative; border: 0; background: none; padding: 6px 0; color: var(--muted); font-weight: 500; white-space: nowrap;
  transition: color var(--dur-fast) var(--ease-out);
}
.seg button:hover { color: var(--secondary); }
.seg button[aria-pressed="true"] { color: var(--text); }
.seg button[aria-pressed="true"]::after { content: ""; position: absolute; left: 0; right: 0; bottom: 0; height: 1px; background: var(--accent); }

.select {
  height: 30px; padding: 0 28px 0 10px; border-radius: var(--radius-control); border: 1px solid var(--control);
  background: var(--surface) url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M1 1l4 4 4-4' stroke='%238a8c92' fill='none' stroke-width='1.5'/%3E%3C/svg%3E") no-repeat right 10px center;
  appearance: none; color: var(--text); font-size: 13px; font-weight: 500; max-width: 100%;
}

/* range input: a real track + fill behind a transparent native range (fill can start at 0 for +/- sliders) */
.range-wrap { position: relative; height: 28px; }
.range-wrap .track, .range-wrap .fill { position: absolute; top: 13px; height: 2px; border-radius: 2px; pointer-events: none; }
.range-wrap .track { left: 0; right: 0; background: var(--control); }
.range-wrap .fill { background: var(--secondary); }
.range-wrap .zero { position: absolute; top: 9px; width: 1px; height: 10px; background: var(--control); pointer-events: none; }
.range { position: relative; -webkit-appearance: none; appearance: none; width: 100%; height: 28px; background: none; margin: 0; cursor: pointer; }
.range::-webkit-slider-runnable-track { height: 2px; background: transparent; }
.range::-moz-range-track { height: 2px; background: transparent; }
.range::-webkit-slider-thumb {
  -webkit-appearance: none; width: 16px; height: 16px; margin-top: -7px; border-radius: 50%;
  background: #fff; border: 0; box-shadow: 0 0 0 4px var(--surface);
  transition: transform var(--dur-fast) var(--ease-out);
}
.range::-moz-range-thumb { width: 16px; height: 16px; border-radius: 50%; background: #fff; border: 0; }
.range:active::-webkit-slider-thumb { transform: scale(1.15); }
.range:focus-visible { outline: none; }
.range:focus-visible::-webkit-slider-thumb { box-shadow: 0 0 0 4px var(--surface), 0 0 0 6px var(--accent); }

/* ---------------------------------------------------------------- cards */
.card { background: var(--surface); border-radius: var(--radius-card); padding: var(--card-pad); box-shadow: var(--shadow); min-width: 0; }
.card-head { display: flex; align-items: baseline; justify-content: space-between; gap: var(--s3); margin-bottom: var(--s4); flex-wrap: wrap; }
.card-head p { color: var(--muted); font-size: var(--fs-small); }

/* ---------------------------------------------------------------- lab layout */
.lab {
  display: grid; grid-template-columns: 320px minmax(0, 1fr); gap: var(--gap);
  padding: var(--pad); align-items: start; max-width: 1680px; margin: 0 auto; width: 100%;
}
.side, .main { display: flex; flex-direction: column; gap: var(--gap); min-width: 0; }
.title-row { display: flex; align-items: flex-start; justify-content: space-between; gap: var(--s4); }
.title-row .finding { margin-top: 6px; color: var(--secondary); }
.finding strong { color: var(--text); font-weight: 600; }
.finding .up { color: var(--positive); }
.duo { display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr); gap: var(--gap); }

/* samples */
.samples { display: flex; flex-direction: column; gap: 2px; margin: 0; padding: 0; list-style: none; }
.sample {
  display: grid; grid-template-columns: 52px minmax(0, 1fr); gap: var(--s3); align-items: center; width: 100%;
  padding: 8px; border: 0; border-radius: var(--radius-card); background: none; text-align: left;
  transition: background-color var(--dur-fast) var(--ease-out);
}
.sample:hover { background: var(--raised); }
.sample[aria-pressed="true"] { background: var(--raised); }
.sample img, .sample .thumb-skel { width: 52px; height: 52px; border-radius: var(--radius-thumb); object-fit: cover; background: var(--raised); }
.sample-name { display: block; font-weight: 500; line-height: 1.3; position: relative; width: fit-content; max-width: 100%; }
.sample[aria-pressed="true"] .sample-name::after { content: ""; position: absolute; left: 0; right: 0; bottom: -2px; height: 1px; background: var(--accent); }
.sample-meta { display: block; color: var(--muted); font-size: var(--fs-small); margin-top: 2px; }

.drop {
  display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 4px; text-align: center;
  min-height: 96px; margin-top: var(--s4); padding: var(--s4); border: 1px dashed var(--control); border-radius: var(--radius-card);
  color: var(--secondary); transition: border-color var(--dur-fast) var(--ease-out), background-color var(--dur-fast) var(--ease-out);
  cursor: pointer; width: 100%; background: none;
}
.drop:hover, .drop.over { border-color: var(--secondary); background: var(--raised); }
.drop strong { color: var(--text); font-weight: 600; }
.drop .small { color: var(--muted); }

/* simulator */
.slider { display: grid; gap: 2px; }
.slider + .slider { margin-top: var(--s3); }
.slider-top { display: flex; justify-content: space-between; align-items: baseline; gap: var(--s3); }
.slider-top label { font-weight: 500; }
.slider-ends { display: flex; justify-content: space-between; color: var(--muted); font-size: var(--fs-tiny); }
.sim-foot { display: flex; justify-content: space-between; align-items: center; margin-top: var(--s4); padding-top: var(--s4); border-top: 1px solid var(--rule); gap: var(--s3); flex-wrap: wrap; }

/* ---------------------------------------------------------------- viewer */
.viewer-head { display: flex; align-items: center; gap: var(--s2); flex-wrap: wrap; margin-bottom: var(--s3); }
.viewer-head .spacer { flex: 1; }
.well { position: relative; background: var(--inset); border-radius: var(--radius-thumb); overflow: hidden; }
.compare {
  position: relative; margin: 0 auto; width: 100%; user-select: none; -webkit-user-select: none;
  touch-action: pan-y; cursor: crosshair; overflow: hidden;
}
.compare img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: contain; transition: opacity var(--dur) var(--ease-out); }
.compare .layer-b { clip-path: inset(0 0 0 var(--split, 50%)); }
.compare.busy img { opacity: 0.55; }
.split-line { position: absolute; top: 0; bottom: 0; left: var(--split, 50%); width: 1px; background: rgba(255, 255, 255, 0.85); pointer-events: none; }
.split-handle {
  position: absolute; top: 50%; left: var(--split, 50%); width: 36px; height: 36px; margin: -18px 0 0 -18px;
  border-radius: 50%; background: #fff; color: #111; border: 0; display: grid; place-items: center;
  box-shadow: var(--shadow-float); cursor: ew-resize; touch-action: none;
  transition: transform var(--dur-fast) var(--ease-out);
}
.split-handle:active { transform: scale(0.94); }
.split-handle::before { content: ""; position: absolute; inset: -6px; } /* 48px hit area */
.corner {
  position: absolute; top: 10px; padding: 3px 8px; border-radius: 4px; font-size: var(--fs-small); font-weight: 500;
  background: rgba(14, 14, 17, 0.78); color: #fff; pointer-events: none; white-space: nowrap;
}
.corner.left { left: 10px; }
.corner.right { right: 10px; }
.corner.right.hybrid { box-shadow: inset 0 -1px 0 var(--accent); }
.lens-box { position: absolute; border: 1px solid #fff; box-shadow: 0 0 0 1px rgba(0, 0, 0, 0.6); pointer-events: none; }
.progress { position: absolute; left: 0; right: 0; top: 0; height: 2px; overflow: hidden; z-index: 3; }
.progress::after { content: ""; position: absolute; top: 0; bottom: 0; width: 30%; background: #fff; animation: slide 1.1s var(--ease-out) infinite; }
@keyframes slide { from { left: -30%; } to { left: 100%; } }
.status-chip { position: absolute; right: 10px; bottom: 10px; z-index: 3; }
.viewer-error {
  position: absolute; inset: 0; z-index: 4; display: grid; place-items: center; padding: var(--s6);
  background: rgba(14, 14, 17, 0.86); text-align: center;
}
.viewer-error .box { max-width: 380px; display: grid; gap: var(--s2); justify-items: center; }
.viewer-error .err-mark { width: 8px; height: 8px; border-radius: 50%; background: var(--negative); }

/* loupe */
.loupe-head { display: flex; justify-content: space-between; align-items: baseline; gap: var(--s3); margin: var(--s4) 0 var(--s2); flex-wrap: wrap; }
.loupe { display: grid; grid-template-columns: repeat(var(--n, 3), minmax(0, 1fr)); gap: var(--s3); }
.loupe figure { margin: 0; min-width: 0; }
.lens {
  aspect-ratio: 3 / 2; width: 100%; border-radius: var(--radius-thumb); background-color: var(--inset);
  background-repeat: no-repeat; image-rendering: pixelated; image-rendering: crisp-edges;
}
.loupe figcaption { display: flex; justify-content: space-between; gap: var(--s2); margin-top: 6px; font-size: var(--fs-small); color: var(--muted); }
.loupe figcaption b { color: var(--text); font-weight: 500; position: relative; }
.loupe figure.hybrid figcaption b::after { content: ""; position: absolute; left: 0; right: 0; bottom: -2px; height: 1px; background: var(--accent); }

/* ---------------------------------------------------------------- metrics table */
.table { width: 100%; border-collapse: collapse; }
.table th { font-size: var(--fs-tiny); font-weight: 400; color: var(--muted); text-align: left; padding: 0 0 8px; }
.table td { height: var(--row-height); border-top: 1px solid var(--rule); padding: 0; }
.table th.num, .table td.num { text-align: right; padding-left: var(--s3); }
.table td.best { font-weight: 600; }
.table tr.hybrid td:first-child { box-shadow: inset 1px 0 0 var(--accent); padding-left: 10px; }
.table td:first-child { font-weight: 500; }
.table .unit { color: var(--muted); font-size: 11px; margin-left: 2px; }
.table .dash { color: var(--muted); }
.table-note { margin-top: var(--s3); color: var(--muted); font-size: var(--fs-small); }

/* route card */
.figures { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); margin-bottom: var(--s4); }
.figure { padding: 0 var(--s3); border-left: 1px solid var(--rule); min-width: 0; }
.figure:first-child { padding-left: 0; border-left: 0; }
.figure .label { color: var(--muted); font-size: var(--fs-tiny); display: block; }
.figure .value { font-size: 18px; display: block; margin-top: 2px; white-space: nowrap; }
.reasons { margin: 0; padding: 0; list-style: none; display: grid; gap: 8px; }
.reasons li { display: grid; grid-template-columns: 14px minmax(0, 1fr); gap: 8px; color: var(--secondary); }
.reasons li::before { content: ""; width: 5px; height: 5px; border-radius: 50%; background: var(--control); margin-top: 8px; }
.route-pill { margin-bottom: var(--s3); }

/* pipeline strip */
.timebar { display: flex; height: 6px; border-radius: 3px; overflow: hidden; gap: 1px; margin: var(--s2) 0 var(--s4); background: var(--rule); }
.timebar span { display: block; min-width: 2px; background: var(--control); }
.timebar span.core { background: var(--accent); }
.stages { display: grid; grid-auto-flow: column; grid-auto-columns: 196px; gap: var(--s3); overflow-x: auto; scroll-snap-type: x mandatory; padding-bottom: var(--s2); overscroll-behavior-x: contain; }
.stage { scroll-snap-align: start; margin: 0; min-width: 0; }
.stage .shot { aspect-ratio: 4 / 3; width: 100%; border-radius: var(--radius-thumb); background: var(--inset); object-fit: cover; }
.stage .shot.mosaic { image-rendering: pixelated; }
.stage-top { display: flex; justify-content: space-between; gap: var(--s2); margin-top: 8px; }
.stage-top b { font-weight: 500; font-size: 13px; }
.stage-top .num { color: var(--secondary); font-size: var(--fs-tiny); white-space: nowrap; }
.stage p { color: var(--muted); font-size: var(--fs-small); margin-top: 2px; }
.stage .step { color: var(--muted); font-size: 11px; }

/* skeletons (flat, no shimmer) */
.skel { background: var(--raised); border-radius: 4px; }

/* notes */
.notes { margin-top: var(--s3); display: grid; gap: 4px; color: var(--muted); font-size: var(--fs-small); }

/* ---------------------------------------------------------------- results */
.results { padding: var(--pad); max-width: 1180px; margin: 0 auto; width: 100%; display: grid; gap: var(--gap); }
.results .grid2 { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: var(--gap); }
.results .grid3 { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: var(--gap); }
@media (max-width: 1180px) { .results .grid3 { grid-template-columns: minmax(0, 1fr); } }
.pending { display: grid; gap: var(--s3); }
.pending ul { margin: 0; padding-left: 18px; color: var(--secondary); display: grid; gap: 4px; }
.chart text { fill: var(--muted); font: 11px var(--mono); }
.chart .gridline { stroke: var(--grid); stroke-width: 1; }
.legend { display: flex; gap: var(--s4); flex-wrap: wrap; font-size: var(--fs-small); color: var(--secondary); }
.legend span { display: inline-flex; align-items: center; gap: 6px; }
.legend i { width: 10px; height: 2px; display: inline-block; }
.bars { display: grid; gap: var(--s3); }
.bar-row { display: grid; grid-template-columns: 150px minmax(0, 1fr) 84px; gap: var(--s3); align-items: center; }
.bar-track { height: 8px; background: var(--rule); border-radius: 4px; overflow: hidden; }
.bar-fill { height: 100%; background: var(--chart-neutral-2); border-radius: 4px; }
.bar-fill.accent { background: var(--accent); }
.gallery { display: grid; grid-template-columns: minmax(0, 1fr); gap: var(--s8); }
.gallery figure { margin: 0; }
.gallery img { border-radius: var(--radius-thumb); width: 100%; height: auto; background: var(--inset); }
.strip-labels { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); margin-top: 6px; text-align: center; }

footer.foot { padding: var(--s6) var(--pad) var(--s8); color: var(--muted); font-size: var(--fs-small); max-width: 1680px; margin: 0 auto; width: 100%; }
footer.foot p + p { margin-top: 4px; }

/* ---------------------------------------------------------------- responsive */
@media (max-width: 1180px) {
  .duo { grid-template-columns: minmax(0, 1fr); }
}
@media (max-width: 900px) {
  .brand-sub { display: none; }
  .lab { display: flex; flex-direction: column; align-items: stretch; }
  .side, .main { display: contents; }
  .o-title { order: 1; } .o-input { order: 2; } .o-viewer { order: 3; } .o-duo { order: 4; }
  .o-sim { order: 5; } .o-router { order: 6; } .o-pipe { order: 7; }
  .samples { flex-direction: row; overflow-x: auto; gap: var(--s2); scroll-snap-type: x mandatory; padding-bottom: 4px; }
  .samples li { flex: 0 0 132px; scroll-snap-align: start; }
  .sample { grid-template-columns: minmax(0, 1fr); padding: 6px; }
  .sample img, .sample .thumb-skel { width: 100%; height: 84px; }
  .figures { grid-template-columns: repeat(2, minmax(0, 1fr)); row-gap: var(--s3); }
  .figure:nth-child(3) { padding-left: 0; border-left: 0; }
  .results .grid2, .results .grid3, .gallery { grid-template-columns: minmax(0, 1fr); }
  .bar-row { grid-template-columns: 110px minmax(0, 1fr) 72px; }
}
@media (max-width: 640px) {
  .topbar { gap: var(--s4); }
  .topbar .model-pill { display: none; }
  .title-row { flex-direction: column; }
  .title-row .btn { align-self: stretch; height: 44px; }
  .viewer-head .select { flex: 1 1 40%; height: 36px; }
  .loupe { gap: var(--s3); grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .btn { min-height: 40px; }
  .seg button { min-height: 40px; }
  /* the stage strip becomes a list of thumbnail rows: every stage visible, nothing scrolls sideways */
  .stages { grid-auto-flow: row; grid-auto-columns: auto; grid-template-columns: minmax(0, 1fr); overflow: visible; scroll-snap-type: none; gap: var(--s3); }
  .stage { display: grid; grid-template-columns: 104px minmax(0, 1fr); column-gap: var(--s3); align-items: start; }
  .stage .shot { grid-row: span 2; }
  .stage-top { margin-top: 0; }
}

/* tab switch: a short crossfade (the sticky top bar stays put) */
.topbar { view-transition-name: topbar; }
::view-transition-old(root), ::view-transition-new(root) { animation-duration: 160ms; animation-timing-function: var(--ease-out); }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition-duration: 0ms !important; animation: none !important; scroll-behavior: auto !important; }
  .progress::after { left: 0; width: 100%; opacity: 0.6; }
}

/* ---------------------------------------------------------------- ux preflight */
/* #13 hit targets: on touch screens every control is at least 44px tall (sliders included) */
@media (pointer: coarse) {
  .btn, .seg button, .select, .tab { min-height: 44px; }
  .btn.text { min-height: 44px; padding: 0 8px; }
  .range-wrap, .range { height: 44px; }
  .range-wrap .track, .range-wrap .fill { top: 21px; }
  .range-wrap .zero { top: 17px; }
  .sample { min-height: 44px; }
}

/* #14 safe areas (index.html sets viewport-fit=cover): nothing sits under a notch or the home bar */
.topbar { padding-left: max(var(--pad), env(safe-area-inset-left)); padding-right: max(var(--pad), env(safe-area-inset-right)); }
.lab, .results { padding-left: max(var(--pad), env(safe-area-inset-left)); padding-right: max(var(--pad), env(safe-area-inset-right)); }
footer.foot { padding-left: max(var(--pad), env(safe-area-inset-left)); padding-right: max(var(--pad), env(safe-area-inset-right));
  padding-bottom: max(var(--s8), calc(env(safe-area-inset-bottom) + var(--s4))); }

/* #17 balanced headings, no orphan words in paragraphs */
h1, h2, h3 { text-wrap: balance; }
p, li, figcaption { text-wrap: pretty; }

/* #18 continuous (squircle) corners where supported; others keep the plain radius */
.card, .well, .drop, .sample, .lens, .stage .shot, .gallery img { corner-shape: squircle; }