/* THE SHEET + Tonal Spine (owner B). Palette tokens only (base.css); #000 / #fff appear solely as
   blend operands of the tonal veil, never as visible colour. Geometry is inline, from layout.js. */

/* ------------------------------------------------------------------ sheet + sections */

#sheet {
  position: relative;
  width: 100%;
  overflow-x: clip;
  touch-action: pan-y pinch-zoom;
}
/* frozen: the camera is the viewport; clipping keeps its layer viewport-sized during the move */
#cam.is-frozen { position: fixed; inset: 0; overflow: hidden; transform-origin: 0 0; }

.s-sec {
  position: absolute; left: 0; width: 100%;
  margin: 0; padding: 0;
  content-visibility: auto;
}
#sheet.is-intro .s-sec:not(.s-sec-front) { visibility: hidden; }

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

/* ------------------------------------------------------------------ figures (§5.4–5.5) */

.s-fig, .s-band { position: absolute; margin: 0; }
.s-link {
  position: absolute; inset: 0; display: block;
  overflow: hidden; isolation: isolate;
  background: var(--paper);
  cursor: default;                                   /* §5.8: no cursor change, marks do the talking */
  -webkit-tap-highlight-color: transparent;
  -webkit-touch-callout: none;
}
.s-link:focus-visible { outline: none; }
/* an intro-skipping tap or click must not also open what lies under it (§4.1) */
html.intro-live .s-link, html.intro-run .s-link { pointer-events: none; }
/* paper: V's edges fade into the page across the empty pad (widths per side from sheet.js, never
   over ink), so a scan whose paper sits a hair off --paper shows no rectangle (§10.1 ②) */
.s-fig[data-ground="paper"] > .s-link {
  -webkit-mask-image:
    linear-gradient(to right, transparent, #000 var(--fl, 0px), #000 calc(100% - var(--fr, 0px)), transparent),
    linear-gradient(to bottom, transparent, #000 var(--ft, 0px), #000 calc(100% - var(--fb, 0px)), transparent);
  -webkit-mask-composite: source-in;
  mask-image:
    linear-gradient(to right, transparent, #000 var(--fl, 0px), #000 calc(100% - var(--fr, 0px)), transparent),
    linear-gradient(to bottom, transparent, #000 var(--ft, 0px), #000 calc(100% - var(--fb, 0px)), transparent);
  mask-composite: intersect;
}
.s-img {
  position: absolute; display: block; max-width: none; margin: 0;
  mix-blend-mode: multiply;                          /* scan white × paper = paper */
  user-select: none; -webkit-user-select: none; -webkit-user-drag: none;
}
.s-fig[data-wk] .s-img, .s-band[data-wk] .s-img { filter: brightness(var(--wk, 1)); }
/* Not yet revealed: the plate is not painted at all (the paper veil hides it anyway). Under the
   camera's fractional scale (detail close, §6.3) the veil's anti-aliased edge let a 1 px sliver of
   the scan's edge through, a hairline the height of the figure. The frontispiece stays painted under
   its cover (LCP, base.css). */
.s-fig:not(.s-v-front):not(.is-revealing):not(.is-revealed) .s-img,
.s-band:not(.is-revealing):not(.is-revealed) .s-img { visibility: hidden; }
[data-ground="toned"] > .s-link > .s-img,
[data-ground="dark"] > .s-link > .s-img { mix-blend-mode: normal; filter: none; }
.s-fig[data-ground="toned"] > .s-link,
.s-fig[data-ground="dark"] > .s-link {             /* a physical sheet lying on the sheet */
  box-shadow: 0 1px 1px rgba(0, 0, 0, .08), 0 14px 32px -18px rgba(0, 0, 0, .45);
  transition: box-shadow var(--d-240) var(--ease-out);
}

/* tonal ceiling (§5.7): result = max(img·paper, veil) per channel; the veil darkens to #000
   (sheet.js runs it on WAAPI; the classes below are the end states) */
.s-veil {
  position: absolute; inset: 0;
  background-color: var(--paper);
  mix-blend-mode: lighten;
  pointer-events: none;
}
[data-ground="dark"] > .s-link > .s-veil {        /* dark paper: min(img, veil), light strokes emerge */
  mix-blend-mode: darken;
  background-color: var(--ground, var(--night));
}
.is-revealing > .s-link > .s-veil { background-color: #000; }
.is-revealing[data-ground="dark"] > .s-link > .s-veil { background-color: #fff; }
.is-revealed > .s-link > .s-veil { display: none; }

/* crop marks: placeholder in --2h until the reveal, drawn in --ink on hover / focus (§5.8) */
.s-marks { position: absolute; overflow: visible; fill: none; pointer-events: none; }
.s-mk { stroke-width: 1px; vector-effect: non-scaling-stroke; stroke-linecap: butt; }
.s-mk-ph { stroke: var(--2h); transition: opacity var(--d-160) linear; }
.is-revealing .s-mk-ph, .is-revealed .s-mk-ph { opacity: 0; }
.s-mk-hv {
  stroke: var(--ink);
  stroke-dasharray: 0 1;                             /* pathLength = 4: one unit per L */
  transition: stroke-dasharray var(--d-160) var(--ease-out);
}
.s-link:focus-visible ~ .s-marks .s-mk-hv { stroke-dasharray: 1 0; }
@media (hover: hover) and (pointer: fine) {              /* no sticky hover after a touch */
  .s-link:hover ~ .s-marks .s-mk-hv { stroke-dasharray: 1 0; }
}

/* keyboard focus: inverted catalogue number over the top-left corner */
.s-tag {
  position: absolute; z-index: 1;
  padding: 3px 6px;
  font: 500 11px/16px var(--mono); letter-spacing: .08em; text-transform: uppercase; font-feature-settings: "tnum";
  white-space: nowrap;
  background: var(--ink); color: var(--paper);
  opacity: 0; pointer-events: none;
  transition: opacity var(--d-160) linear;
}
.s-link:focus-visible ~ .s-tag { opacity: 1; }

/* ------------------------------------------------------------------ captions */

.s-cap {
  position: absolute; margin: 0;
  color: var(--ink);
  opacity: 0;
  transition: opacity var(--d-240) var(--ease-out);
}
.is-revealing > .s-cap, .is-revealed > .s-cap { opacity: 1; }
.s-cap[data-valign="bottom"] { transform: translateY(-100%); }
/* Set line by line while the drawing develops: each line rises out of its own baseline mask, the
   frontispiece's gesture (§4.1: 480, 80 apart). Only a veiled reveal plays it; an instant one (same
   session, detail target) has no .is-revealing and simply stands there. */
@media (prefers-reduced-motion: no-preference) {
  .s-fig:not(.is-revealing):not(.is-revealed) > .s-cap > :is(.s-l1, .s-t, .s-l3, .s-l4),
  .s-band:not(.is-revealing):not(.is-revealed) > .s-bcap {
    transform: translateY(calc(100% + .3em));
    clip-path: inset(0 -.3em 100% -.3em);
  }
  /* opacity keeps .s-l3's own 160 ms fade (materials on hover / focus) */
  .is-revealing > .s-cap > :is(.s-l1, .s-t, .s-l3, .s-l4), .s-band.is-revealing > .s-bcap {
    clip-path: inset(-.3em);
    transition: opacity var(--d-160) linear,
      transform var(--d-480) var(--ease-out) var(--cd, 0ms), clip-path var(--d-480) var(--ease-out) var(--cd, 0ms);
  }
  .s-band.is-revealing > .s-bcap { transition-duration: var(--d-240), var(--d-480), var(--d-480); transition-timing-function: var(--ease-out); }
  .is-revealing > .s-cap > .s-t { --cd: 80ms; }
  .is-revealing > .s-cap > .s-l3 { --cd: 160ms; }
  .is-revealing > .s-cap > .s-l4 { --cd: 240ms; }
}
.s-cap[data-align="right"] { text-align: right; }
.s-cap[data-align="right"] .s-t { margin-left: auto; }
.s-l1, .s-l3, .s-bcap {
  display: block;
  font: 400 11px/16px var(--mono); letter-spacing: .08em; text-transform: uppercase;
  font-feature-settings: "tnum";
  color: var(--graphite);
  overflow-wrap: anywhere;
}
.s-t {
  display: block; max-width: 22ch; margin: 6px 0;
  font: italic 400 20px/22px var(--serif); letter-spacing: -.01em;
  text-wrap: balance; overflow-wrap: break-word;
}
.s-l3 { opacity: 0; transition: opacity var(--d-160) linear; }
.s-link:focus-visible ~ .s-cap .s-l3 { opacity: 1; }
@media (hover: hover) and (pointer: fine) {
  .s-link:hover ~ .s-cap .s-l3 { opacity: 1; }
}

.s-cap-solo .s-l1 { margin-bottom: 10px; }
.s-cap-solo .s-t {
  max-width: none; margin: 0 0 12px;
  font: 400 var(--fs, 44px)/.95 var(--serif); letter-spacing: -.01em;
}
.s-cap-solo .s-l3 { opacity: 1; }
.s-cap-solo .s-l4 {
  display: block; margin-top: 4px;
  font: 400 12px/18px var(--mono); font-feature-settings: "tnum"; color: var(--graphite);
}

.s-cap-cell {
  font: italic 400 15px/16px var(--serif); letter-spacing: -.01em;
  display: -webkit-box; -webkit-box-orient: vertical; -webkit-line-clamp: 2; overflow: hidden;
}
.s-day {
  position: absolute; pointer-events: none;
  font: 400 11px/14px var(--mono); font-feature-settings: "tnum"; letter-spacing: .04em;
  color: var(--graphite);
}
#sheet[data-bp="xs"] .s-day { font-size: 9px; line-height: 10px; letter-spacing: 0; }

/* ------------------------------------------------------------------ bands (§5.8) */

.s-bimg { transform: translate3d(0, 0, 0); }
.s-bcap { position: absolute; margin: 0; }

/* ------------------------------------------------------------------ block decorations */

.s-front, .s-ch, .s-shead, .s-cal, .s-colo { position: absolute; left: 0; width: 100%; }

.s-more {
  position: absolute; margin: 0;
  display: flex; flex-direction: column; align-items: center; gap: 8px;
  transform: translateX(-50%);
  font: 400 12px/16px var(--mono); font-feature-settings: "tnum"; color: var(--graphite);
  white-space: nowrap; pointer-events: none;
  opacity: 0;
  transition: opacity var(--hd, 320ms) var(--ease-out);
}
.s-more i {
  display: block; width: 1px; height: 40px; background: var(--ink);
  transform: scaleY(0); transform-origin: 50% 0;
  transition: transform var(--hd, 320ms) var(--ease-out);
}
.s-more.is-in { opacity: 1; }
.s-more.is-in i { transform: none; }
#sheet.is-intro .s-more { visibility: hidden; }

.s-year {
  position: absolute; margin: 0;
  font-family: var(--serif); font-weight: 400; line-height: 1; letter-spacing: -.02em;
  color: var(--numeral);
  white-space: nowrap; user-select: none; -webkit-user-select: none;
}
.s-count {
  position: absolute; margin: 0;
  font: 400 11px/16px var(--mono); letter-spacing: .08em; text-transform: uppercase; font-feature-settings: "tnum";
  color: var(--graphite); white-space: nowrap;
}

.s-stitle {
  position: absolute; margin: 0;
  font-family: var(--serif); font-weight: 400; letter-spacing: -.01em;
  text-wrap: balance;
}
.s-smeta, .s-cal-meta {
  position: absolute; margin: 0;
  font: 400 11px/16px var(--mono); letter-spacing: .08em; text-transform: uppercase; font-feature-settings: "tnum";
  color: var(--graphite);
}
.s-sdesc {
  position: absolute; margin: 0;
  font: italic 400 20px/22px var(--serif); letter-spacing: -.01em;
  color: var(--graphite);
  text-wrap: pretty;
}

.s-cal-title {
  position: absolute; margin: 0;
  font-family: var(--serif); font-weight: 400; letter-spacing: -.01em; white-space: nowrap;
}
.s-wd { position: absolute; left: 0; width: 100%; }
.s-wd span {
  position: absolute; top: 8px;
  font: 400 11px/16px var(--mono); letter-spacing: .08em; color: var(--graphite);
}
.s-cal.is-xs .s-wd span { font-size: 9px; letter-spacing: .02em; }
.s-miss { position: absolute; }
.s-miss .s-day { left: 0; top: 0; }
.s-dash {
  position: absolute; inset: 0;
  display: grid; place-items: center;
  font: 400 20px/1 var(--serif); color: var(--2h);
}
.s-cal.is-xs .s-dash { font-size: 14px; }

.s-colo {
  box-sizing: border-box;
  display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 10px;
  padding: 0 var(--m);
  text-align: center;
}
.s-colo::before {                                    /* the sheet's last hairline */
  content: ""; position: absolute; top: 0; left: var(--m); right: var(--m);
  height: var(--hair-w); background: var(--hair);
}
.s-colo-mark {
  display: inline-block;
  font: 400 64px/1 var(--serif); letter-spacing: -.01em;
  transform: rotate(180deg);                         /* "ykcu7" turned reads ㄥnɔʞʎ (§2.2) */
  transition: transform var(--d-480) var(--ease-io);
}
/* the sheet ends where it began: the mark turns back (as the header logo does) and leads to the top */
.s-colo-top {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 44px; min-height: 44px; margin-bottom: 18px; padding: 4px 8px;
  color: var(--ink); text-decoration: none;
}
.s-colo-top:focus-visible .s-colo-mark { transform: rotate(0deg); }
@media (hover: hover) and (pointer: fine) {
  .s-colo-top:hover .s-colo-mark { transform: rotate(0deg); }
}
.s-nw { white-space: nowrap; }
.s-colo-l {
  margin: 0; text-wrap: balance;
  font: 400 11px/16px var(--mono); letter-spacing: .08em; text-transform: uppercase; font-feature-settings: "tnum";
  color: var(--graphite);
}
.s-colo-a {
  display: inline-flex; align-items: center; min-height: 44px;
  color: var(--ink); text-decoration: none;
}
.s-colo-a:focus-visible {
  text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: 4px;
}
@media (hover: hover) and (pointer: fine) {
  .s-colo-a:hover { text-decoration: underline; text-decoration-thickness: 1px; text-underline-offset: 4px; }
}
.s-rot { display: inline-block; transform: rotate(180deg); font-family: var(--serif); font-size: 15px; letter-spacing: 0; text-transform: none; }

/* ------------------------------------------------------------------ focus mode (camera, §5.12) */

#sheet .s-fade { transition: opacity var(--fm, 320ms) var(--ease-io) var(--fmd, 0ms); }
#sheet.is-focus .s-fade { opacity: 0; pointer-events: none; }
#sheet.is-focus .s-fig.is-target { opacity: 1; }
#sheet.is-focus .is-target > .s-cap,
#sheet.is-focus .is-target > .s-marks,
#sheet.is-focus .is-target > .s-tag,
#sheet.is-focus .is-target > .s-day { opacity: 0; transition: opacity var(--fm, 480ms) var(--ease-io) var(--fmd, 0ms); }
#sheet.is-focus .s-more { opacity: 0; }

/* ------------------------------------------------------------------ reduced motion (§8.2) */

@media (prefers-reduced-motion: reduce) {
  .s-veil { display: none; }
  .s-link { opacity: 0; }                            /* 0 → 1 over 160 ms on WAAPI (sheet.js) */
  .is-revealed > .s-link { opacity: 1; }
  .s-mk-hv, .s-more, .s-more i, .s-cap, .s-l3, .s-colo-mark { transition-duration: 0ms; }
  .s-bimg { transform: none !important; }
}

/* ------------------------------------------------------------------ Tonal Spine (§5.9) */

#spine.s-spine { position: fixed; z-index: 30; pointer-events: none; }
.s-spine[data-orient="v"] { top: 64px; right: 0; bottom: 32px; width: 48px; }
.s-spine[data-orient="h"] {
  left: max(16px, env(safe-area-inset-left)); right: max(16px, env(safe-area-inset-right));
  bottom: calc(env(safe-area-inset-bottom, 0px) + 10px); height: 44px;
}
/* the strip rests on paper: text and art passing the bottom edge fade out under it, never
   under the ticks (layout.js keeps the first screen above it) */
.s-spine[data-orient="h"]::before {
  content: ""; position: absolute; pointer-events: none;
  left: calc(-1 * max(16px, env(safe-area-inset-left))); right: calc(-1 * max(16px, env(safe-area-inset-right)));
  top: -18px; bottom: calc(-10px - env(safe-area-inset-bottom, 0px));
  background: linear-gradient(to top, var(--paper) 58%, transparent);
}
.s-spine-canvas { position: absolute; inset: 0; width: 100%; height: 100%; display: block; }
.s-spine[data-orient="h"] .s-spine-canvas { opacity: .35; transition: opacity var(--d-240) var(--ease-out); }
.s-spine[data-orient="h"].is-active .s-spine-canvas { opacity: 1; transition-duration: var(--d-160); }
.s-spine-track {
  position: absolute; pointer-events: auto;
  touch-action: none; user-select: none; -webkit-user-select: none;
  -webkit-tap-highlight-color: transparent;
  outline: none;
}
.s-spine[data-orient="v"] .s-spine-track { top: 0; right: 0; bottom: 0; width: 32px; }
.s-spine[data-orient="h"] .s-spine-track { inset: 0; }
.s-spine-track:focus-visible { outline: 1px solid var(--ink); outline-offset: 3px; }
.s-spine-no {                                        /* a flag on the range bracket (x = 10) */
  position: absolute; top: 0; left: 10px;
  padding: 0 4px 0 3px;
  font: 400 11px/16px var(--mono); letter-spacing: .04em; font-feature-settings: "tnum";
  color: var(--ink); background: var(--paper);
  box-shadow: inset 1px 0 var(--ink);
  pointer-events: none; white-space: nowrap;
}
.s-spine-card {
  position: absolute; top: 0;
  display: flex; flex-direction: column; gap: 8px;
  width: max-content; max-width: 240px; padding: 10px;
  background: var(--paper);
  border: var(--hair-w) solid var(--hair);
  opacity: 0; pointer-events: none;
  transition: opacity var(--d-160) linear;
}
.s-spine[data-orient="v"] .s-spine-card { right: 52px; }
.s-spine[data-orient="h"] .s-spine-card { top: auto; left: 0; bottom: 52px; }
.s-spine-card.is-on { opacity: 1; }
.s-spine-card img {
  display: block; width: 96px; height: 96px;
  object-fit: contain; object-position: 0 50%;
  mix-blend-mode: multiply;
}
.s-spine-card span {
  font: 400 11px/16px var(--mono); letter-spacing: .04em; font-feature-settings: "tnum";
  color: var(--ink);
  text-wrap: balance; overflow-wrap: break-word;
}
@media (prefers-reduced-motion: reduce) {
  .s-spine[data-orient="h"] .s-spine-canvas, .s-spine-card { transition-duration: 0ms; }
}