/* ==========================================================================
   OPTIK — An exploded atlas of the camera
   Museum exhibit / field manual on paper.
   Palette per tools/CONTRACT.md:
   paper #f2efe8 · ink #191512 · hairline #d8d2c4 · signal red #c1432f · amber #b07d2b
   ========================================================================== */

:root {
  --paper: #f2efe8;
  --paper-deep: #eae6db;
  --ink: #191512;
  --ink-soft: #4a443c;
  --ink-faint: #6e675b; /* 4.9:1 on paper — WCAG AA for small mono text */
  --hairline: #d8d2c4;
  --hairline-strong: #c4bcab;
  --accent: #c1432f;
  --accent-deep: #9c3524; /* darkened accent: ≥4.5:1 on paper for small text */
  --amber: #b07d2b;

  --serif: "Iowan Old Style", "Palatino", "Palatino Linotype", Georgia, "Times New Roman", serif;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;

  --pad: clamp(16px, 2.4vw, 32px);
  --rail-w: 300px;
  --rail-w-info: 340px;

  --focus-ring: 0 0 0 2px var(--paper), 0 0 0 4px var(--accent);
}

/* ---------- Reset-ish ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3, h4, p, ul, ol { margin: 0; }
ul, ol { padding: 0; list-style: none; }
button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
}
kbd {
  font-family: var(--mono);
  font-size: 0.62rem;
  border: 1px solid var(--hairline-strong);
  border-bottom-width: 2px;
  border-radius: 3px;
  padding: 0.05em 0.4em;
  color: var(--ink-soft);
  background: var(--paper);
  white-space: nowrap;
}

.visually-hidden {
  position: absolute !important;
  width: 1px; height: 1px;
  margin: -1px; padding: 0; border: 0;
  clip: rect(0 0 0 0);
  clip-path: inset(50%);
  overflow: hidden;
  white-space: nowrap;
}

.skip-link {
  position: absolute;
  top: -100px;
  left: 12px;
  z-index: 60;
  background: var(--ink);
  color: var(--paper);
  font-family: var(--mono);
  font-size: 0.75rem;
  padding: 8px 14px;
  text-decoration: none;
  transition: top 120ms ease;
}
.skip-link:focus-visible { top: 8px; }

:focus-visible {
  outline: none;
  box-shadow: var(--focus-ring);
  border-radius: 1px;
}

::selection { background: var(--accent); color: var(--paper); }

/* ==========================================================================
   Layout — three rails on desktop; folds to a single column on small screens
   ========================================================================== */

.layout {
  display: grid;
  min-height: 100vh;
  min-height: 100dvh;
  grid-template-columns: var(--rail-w) minmax(0, 1fr) var(--rail-w-info);
  grid-template-rows: auto 1fr auto;
  grid-template-areas:
    "header header header"
    "catalog stage  info"
    "footer footer footer";
  column-gap: 0;
}

/* Desktop: kiosk behavior — viewport-locked, rails scroll independently */
@media (min-width: 1280px) {
  .layout { height: 100vh; height: 100dvh; }
  .rail, .stage { min-height: 0; }
}

/* ---------- Header ---------- */
.site-header {
  grid-area: header;
  border-bottom: 1px solid var(--ink);
  padding: calc(var(--pad) * 0.9) var(--pad) calc(var(--pad) * 0.7);
}
.site-header__row {
  display: flex;
  align-items: baseline;
  gap: 18px;
  flex-wrap: wrap;
}
.wordmark {
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(2rem, 3.4vw, 2.9rem);
  letter-spacing: 0.22em;
  line-height: 1;
}
.wordmark::first-letter { color: var(--accent); }
.site-subtitle {
  font-style: italic;
  font-size: clamp(0.95rem, 1.4vw, 1.1rem);
  color: var(--ink-soft);
}
.site-edition {
  margin-left: auto;
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
.site-intro {
  max-width: 72ch;
  margin-top: 14px;
  font-size: 0.92rem;
  color: var(--ink-soft);
}

/* ---------- Rails (shared) ---------- */
.rail {
  min-width: 0;
  background: var(--paper);
  overflow-y: auto;
  overscroll-behavior: contain;
}
.rail--catalog {
  grid-area: catalog;
  border-right: 1px solid var(--hairline);
  padding: var(--pad) 0 var(--pad) var(--pad);
}
.rail--info {
  grid-area: info;
  border-left: 1px solid var(--hairline);
  padding: var(--pad) var(--pad) var(--pad) 0;
  overflow-y: auto;
}
.rail-fold { /* <details> wrapper kept visible on desktop */ }
.rail-fold > summary {
  display: none; /* shown only in the collapsible breakpoints */
}
.rail-fold__body > section + section { margin-top: 26px; }
.rail--catalog .rail-fold__body { padding-right: calc(var(--pad) * 0.75); }
.rail--info .rail-fold__body { padding-left: calc(var(--pad) * 0.75); }

.rail-heading {
  font-family: var(--mono);
  font-size: 0.66rem;
  font-weight: 500;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--ink-faint);
  padding-bottom: 8px;
  border-bottom: 1px solid var(--hairline);
  margin-bottom: 4px;
}
.rail-heading .fig {
  color: var(--accent-deep);
}

/* ==========================================================================
   Catalog rows — figure plates, numbered
   ========================================================================== */

.cat-list { display: flex; flex-direction: column; }

.cat-item {
  display: grid;
  grid-template-columns: 3.4em 1fr;
  gap: 2px 10px;
  align-items: baseline;
  width: 100%;
  text-align: left;
  padding: 11px 8px 11px 2px;
  border-bottom: 1px solid var(--hairline);
  position: relative;
  transition: background-color 140ms ease;
}
.cat-item::before { /* index tick */
  content: "";
  position: absolute;
  left: -1px; top: 14px; bottom: 14px;
  width: 2px;
  background: var(--accent);
  transform: scaleY(0);
  transform-origin: top;
  transition: transform 180ms ease;
}
.cat-item:hover { background: var(--paper-deep); }
.cat-item[aria-pressed="true"] { background: var(--paper-deep); }
.cat-item[aria-pressed="true"]::before { transform: scaleY(1); }

.cat-item__no {
  grid-row: span 2;
  font-family: var(--mono);
  font-size: 0.66rem;
  letter-spacing: 0.08em;
  color: var(--ink-faint);
  align-self: start;
  padding-top: 3px;
}
.cat-item[aria-pressed="true"] .cat-item__no { color: var(--accent-deep); }
.cat-item__name {
  font-size: 1.02rem;
  line-height: 1.25;
}
.cat-item__meta {
  font-family: var(--mono);
  font-size: 0.64rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
.cat-item:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}
.cat-item:disabled:hover { background: none; }

/* ---------- Bench controls ---------- */
.controls { display: flex; flex-direction: column; }
.ctl {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  padding: 10px 8px 10px 2px;
  border-bottom: 1px solid var(--hairline);
  font-size: 0.92rem;
  text-align: left;
  transition: background-color 140ms ease;
}
.ctl:hover { background: var(--paper-deep); }
.ctl:disabled { opacity: 0.42; cursor: not-allowed; }
.ctl:disabled:hover { background: none; }
.ctl[aria-pressed="true"] .ctl__label { color: var(--accent-deep); font-style: italic; }
.controls-note {
  margin-top: 10px;
  font-size: 0.78rem;
  color: var(--ink-faint);
  line-height: 1.9;
}

/* ==========================================================================
   Stage
   ========================================================================== */

.stage {
  grid-area: stage;
  position: relative;
  min-height: 420px;
  overflow: hidden;
  background:
    /* registration marks */
    url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='240' height='240' viewBox='0 0 240 240'%3E%3Cg stroke='%23d8d2c4' stroke-width='1' fill='none'%3E%3Cpath d='M12 0v10M0 12h10M228 0v10M240 12h-10M12 240v-10M0 228h10M228 240v-10M240 228h-10'/%3E%3C/g%3E%3Cg stroke='%23d8d2c4' stroke-width='1' opacity='.5'%3E%3Cpath d='M120 110v20M110 120h20'/%3E%3C/g%3E%3C/svg%3E"),
    /* faint technical grid */
    repeating-linear-gradient(0deg, transparent 0 59px, rgba(216, 210, 196, 0.35) 59px 60px),
    repeating-linear-gradient(90deg, transparent 0 59px, rgba(216, 210, 196, 0.35) 59px 60px),
    var(--paper);
  background-position: center, center, center;
  touch-action: none; /* pointer-drag orbit owns the gesture */
}

#stage-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  cursor: grab;
}
#stage-canvas.is-dragging { cursor: grabbing; }
#stage-canvas.is-hovering-part { cursor: pointer; }
#stage-canvas:focus-visible { box-shadow: inset var(--focus-ring); }

/* Leader lines + labels overlay */
.leaders, .labels {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  overflow: visible;
}
.leaders line {
  stroke: var(--ink-soft);
  stroke-width: 1;
  opacity: 0.75;
}
.leaders line.is-active { stroke: var(--accent); }
.leaders circle { fill: var(--ink-soft); }
.leaders circle.is-active { fill: var(--accent); }

.part-label {
  position: absolute;
  top: 0; left: 0;
  pointer-events: auto;
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink);
  background: color-mix(in srgb, var(--paper) 88%, transparent);
  border: 1px solid var(--hairline-strong);
  padding: 3px 7px 2px;
  white-space: nowrap;
  transform: translate(-50%, -50%);
  transition: color 120ms ease, border-color 120ms ease;
  will-change: transform;
}
.part-label:hover { border-color: var(--ink-soft); }
.part-label.is-active {
  color: var(--paper);
  background: var(--accent);
  border-color: var(--accent);
}
.part-label .part-label__no { opacity: 0.6; margin-right: 0.5em; }
.part-label.is-active .part-label__no { opacity: 0.85; }

/* ---------- Stage caption (catalog line under the specimen) ---------- */
.stage-caption {
  position: absolute;
  left: 50%;
  bottom: 14px;
  transform: translateX(-50%);
  max-width: 86%;
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-faint);
  text-align: center;
  pointer-events: none;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

/* ---------- Failure / loading plate ---------- */
.plate {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  text-align: center;
  padding: 24px;
  background:
    repeating-linear-gradient(0deg, transparent 0 59px, rgba(216, 210, 196, 0.35) 59px 60px),
    repeating-linear-gradient(90deg, transparent 0 59px, rgba(216, 210, 196, 0.35) 59px 60px),
    var(--paper);
  z-index: 5;
}
.plate[hidden] { display: none; }
.plate__art {
  width: 110px;
  height: 110px;
  color: var(--ink-soft);
}
.plate__kicker {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--accent-deep);
}
.plate__note {
  max-width: 40ch;
  font-size: 0.9rem;
  font-style: italic;
  color: var(--ink-soft);
}
.plate__retry {
  margin-top: 6px;
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  border: 1px solid var(--ink);
  padding: 8px 18px;
  transition: background-color 140ms ease, color 140ms ease;
}
.plate__retry:hover { background: var(--ink); color: var(--paper); }
.plate--loading .plate__kicker { color: var(--ink-faint); animation: plate-pulse 1.6s ease-in-out infinite; }
@keyframes plate-pulse { 0%, 100% { opacity: 0.45; } 50% { opacity: 1; } }

/* ==========================================================================
   Info panel — the wall text
   ========================================================================== */

.info-kicker {
  font-family: var(--mono);
  font-size: 0.64rem;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--accent-deep);
  margin-bottom: 8px;
}
.info-title {
  font-size: 1.5rem;
  font-weight: 500;
  line-height: 1.15;
}
.info-meta {
  font-family: var(--mono);
  font-size: 0.66rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-top: 6px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--ink);
}
.info-tagline {
  font-style: italic;
  font-size: 1rem;
  color: var(--ink-soft);
  margin-top: 12px;
}
.info-desc { margin-top: 10px; font-size: 0.94rem; }

.info-block { margin-top: 20px; }
.info-block > h3 {
  font-family: var(--mono);
  font-size: 0.64rem;
  font-weight: 500;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--ink-faint);
  padding-bottom: 6px;
  border-bottom: 1px solid var(--hairline);
  margin-bottom: 10px;
}
.info-block p { font-size: 0.88rem; color: var(--ink-soft); }

.spec-list { display: flex; flex-direction: column; }
.spec-list li {
  display: grid;
  grid-template-columns: 1.6em 1fr;
  gap: 8px;
  padding: 7px 0;
  font-size: 0.86rem;
  border-bottom: 1px solid var(--hairline);
}
.spec-list li::before {
  content: counter(spec, decimal-leading-zero);
  counter-increment: spec;
  font-family: var(--mono);
  font-size: 0.62rem;
  color: var(--ink-faint);
  padding-top: 3px;
}
.spec-list { counter-reset: spec; }
.spec-list--tradeoffs li::before { color: var(--accent-deep); }
.spec-list--tradeoffs li { color: var(--ink-soft); }

/* Parts glossary list (also the a11y alternative to raycasting) */
.parts-list { display: flex; flex-direction: column; }
.part-row {
  display: grid;
  grid-template-columns: 2.6em 1fr;
  gap: 8px;
  align-items: baseline;
  width: 100%;
  text-align: left;
  padding: 8px 6px 8px 2px;
  border-bottom: 1px solid var(--hairline);
  transition: background-color 140ms ease;
}
.part-row:hover { background: var(--paper-deep); }
.part-row[aria-pressed="true"] { background: var(--paper-deep); }
.part-row[aria-pressed="true"] .part-row__name { color: var(--accent-deep); }
.part-row__no {
  font-family: var(--mono);
  font-size: 0.64rem;
  color: var(--ink-faint);
}
.part-row[aria-pressed="true"] .part-row__no { color: var(--accent-deep); }
.part-row__name {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.part-blurb {
  margin-top: 16px;
  padding: 14px 14px 12px;
  border: 1px solid var(--ink);
  border-left: 3px solid var(--accent);
}
.part-blurb__name {
  font-family: var(--mono);
  font-size: 0.68rem;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--accent-deep);
  margin-bottom: 8px;
}
.part-blurb__text { font-size: 0.9rem; }

/* Empty-state wall text */
.info-empty__rules {
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--hairline);
  padding: 14px 0;
  margin-top: 12px;
  font-size: 0.9rem;
  color: var(--ink-soft);
}
.info-empty__rules li { padding: 4px 0; display: grid; grid-template-columns: 2em 1fr; gap: 8px; }
.info-empty__rules kbd { justify-self: start; }

/* ---------- Footer / colophon ---------- */
.site-footer {
  grid-area: footer;
  border-top: 1px solid var(--ink);
  padding: 14px var(--pad);
  font-family: var(--mono);
  font-size: 0.64rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-faint);
  text-align: center;
}

/* ==========================================================================
   Breakpoints
   ========================================================================== */

/* 768–1280: rails become collapsible folds over a full-width stage */
@media (max-width: 1279px) {
  .layout {
    grid-template-columns: 1fr;
    grid-template-rows: auto auto 1fr auto auto;
    grid-template-areas:
      "header"
      "catalog"
      "stage"
      "info"
      "footer";
  }
  .stage { min-height: 52vh; }
  .rail--catalog, .rail--info {
    border: 0;
    border-bottom: 1px solid var(--hairline);
    padding: 0 var(--pad);
    overflow: visible;
  }
  .rail--info { border-top: 1px solid var(--hairline); }
  .rail-fold > summary {
    display: flex;
    align-items: center;
    gap: 10px;
    cursor: pointer;
    list-style: none;
    padding: 13px 0;
    font-family: var(--mono);
    font-size: 0.7rem;
    letter-spacing: 0.26em;
    text-transform: uppercase;
    color: var(--ink-soft);
  }
  .rail-fold > summary::-webkit-details-marker { display: none; }
  .rail-fold > summary::before {
    content: "";
    width: 8px; height: 8px;
    border-right: 1px solid var(--ink-soft);
    border-bottom: 1px solid var(--ink-soft);
    transform: rotate(-45deg);
    transition: transform 160ms ease;
  }
  .rail-fold[open] > summary::before { transform: rotate(45deg); }
  .rail-fold > summary:hover { color: var(--ink); }
  .rail-fold__body { padding: 0 0 20px; }
  .rail--catalog .rail-fold__body, .rail--info .rail-fold__body { padding-left: 0; padding-right: 0; }
  .rail--catalog .rail-fold__body {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0 28px;
  }
  .rail--catalog .rail-fold__body > section + section { margin-top: 0; }
  .rail--catalog .controls-section { grid-column: 1 / -1; margin-top: 22px; }
  .controls { flex-direction: row; flex-wrap: wrap; gap: 0 22px; }
  .ctl { border-bottom: 0; border-top: 1px solid var(--hairline); flex: 1 1 160px; }
}

/* <768: single column, stage first, catalog as horizontal scroll chips */
@media (max-width: 767px) {
  .layout {
    grid-template-areas:
      "header"
      "stage"
      "catalog"
      "info"
      "footer";
    grid-template-rows: auto 62vh auto auto auto;
  }
  .site-header { padding-top: 18px; }
  .site-edition { display: none; }
  .rail--catalog .rail-fold__body { display: block; }
  .cat-list {
    flex-direction: row;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
    margin: 0 calc(var(--pad) * -1);
    padding: 4px var(--pad) 10px;
  }
  .cat-list::-webkit-scrollbar { display: none; }
  .cat-item {
    flex: 0 0 auto;
    width: auto;
    grid-template-columns: auto;
    gap: 2px;
    border: 1px solid var(--hairline-strong);
    padding: 9px 14px;
    margin-right: 8px;
    min-width: 128px;
  }
  .cat-item::before { display: none; }
  .cat-item[aria-pressed="true"] { border-color: var(--accent); }
  .cat-item__no { grid-row: auto; padding-top: 0; }
  .part-label { font-size: 9px; padding: 2px 5px 1px; }
}

/* ==========================================================================
   Reduced motion — print-like, instant
   ========================================================================== */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  #stage-canvas { cursor: default; }
}