/* ==========================================================================
   Sections
   ========================================================================== */

/* Sections are opaque and sit above the pinned cover, so Issue #01 rises over
   it instead of the cover scrolling away. They all paint one variable, which
   backdrop.js lerps between each section's mood -- so the ground travels with
   you and there is no seam anywhere to hide. */
main > section,
.colophon {
  position: relative;
  z-index: 1;
  background: var(--bg-live, var(--bg));
}

.hero {
  background: #0b0b0b;
}

/* The join between two sections, drawn rather than hidden: a hairline that
   grows out of the centre as the boundary crosses the screen. */
.seam {
  position: relative;
  z-index: 2;
  height: 0;
  overflow: visible;
}

.seam::before {
  content: '';
  position: absolute;
  inset-inline: 0;
  inset-block-start: -0.5px;
  height: 1px;
  background: linear-gradient(
    to right,
    transparent,
    var(--accent) 50%,
    transparent
  );
  opacity: calc(var(--grow, 0) * 0.5);
  transform: scaleX(calc(0.15 + var(--grow, 0) * 0.85));
}

/* A sheet of paper has an edge, so the interlude keeps one -- but it is bled
   at top and bottom so the arrival still feels like a fade of light. */
.on-paper {
  --bg-live: #e8e4d8;
}

.on-paper::before,
.on-paper::after {
  content: '';
  position: absolute;
  inset-inline: 0;
  height: clamp(2rem, 5vh, 4rem);
  pointer-events: none;
}

.on-paper::before {
  inset-block-start: 0;
  background: linear-gradient(to bottom, rgba(15, 15, 15, 0.32), transparent);
}

.on-paper::after {
  inset-block-end: 0;
  background: linear-gradient(to top, rgba(15, 15, 15, 0.32), transparent);
}

/* ---- #01 origin --------------------------------------------------------- */

.origin-grid {
  display: grid;
  gap: var(--s-7);
  grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
  align-items: start;
}

@media (max-width: 52rem) {
  .origin-grid {
    grid-template-columns: 1fr;
  }
}

/* The route strip. Two nodes and a line, the way a pass prints it. */
.route {
  display: grid;
  grid-template-columns: auto 1fr auto;
  align-items: center;
  gap: var(--s-4);
  padding: var(--s-5);
  border: 1px solid var(--rule);
  border-radius: var(--r-lg);
  background: color-mix(in oklab, var(--bg-raised) 70%, transparent);
}

.route-node {
  display: flex;
  flex-direction: column;
  gap: 2px;
  text-align: center;
}

.route-code {
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  color: var(--accent-fg);
}

.route-place {
  font-weight: 600;
  font-size: var(--fs-small);
}

.route-sub {
  color: var(--fg-faint);
  max-width: 9rem;
}

.route-line {
  position: relative;
  height: 1px;
  background: repeating-linear-gradient(
    to right,
    var(--rule-strong) 0 4px,
    transparent 4px 9px
  );
}

.route-plane {
  position: absolute;
  inset-block-start: 50%;
  inset-inline-start: 0;
  width: 10px;
  height: 10px;
  margin-block-start: -5px;
  background: var(--accent);
  /* A paper dart, pointing the way. */
  clip-path: polygon(0 0, 100% 50%, 0 100%, 22% 50%);
  /* Position driven by scroll progress in JS. */
  translate: calc(var(--flight, 0) * (100cqw - 10px)) 0;
}

.route-line {
  container-type: inline-size;
}


/* ---- #02 four scales ---------------------------------------------------- */

.scales {
  position: relative;
}

/* Sticky readout: the scale you are currently looking at. */
.scale-readout {
  position: sticky;
  inset-block-start: calc(env(safe-area-inset-top, 0px) + var(--s-4));
  z-index: 5;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  padding-block: var(--s-3);
  pointer-events: none;
  /* Screen on the dark ground; multiply where the page turns to paper. */
  mix-blend-mode: screen;
}

.on-paper .scale-readout,
:root[data-theme='light'] .scale-readout {
  mix-blend-mode: multiply;
}

.scale-value {
  font-size: clamp(2.5rem, 9vw, 5rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.04em;
  color: color-mix(in oklab, var(--accent) 42%, transparent);
}

.scale-unit {
  color: var(--fg-faint);
}

.papers {
  counter-reset: paper;
  margin-block-start: calc(var(--s-8) * -1);
}

.paper {
  display: grid;
  grid-template-columns: 6.5rem minmax(0, 1fr);
  gap: var(--s-5);
  padding-block: var(--s-8);
  border-block-end: 1px solid var(--rule);
  align-items: start;
  /* Rows lift on hover; JS writes --lift so the spring, not a transition,
     owns the motion. */
  translate: 0 calc(var(--lift, 0) * -6px);
}

.paper:last-child {
  border-block-end: none;
}

@media (max-width: 44rem) {
  .paper {
    grid-template-columns: 1fr;
    gap: var(--s-3);
    padding-block: var(--s-7);
  }
}

.paper-scale {
  font-size: 1.6rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--fg-faint);
  padding-block-start: 0.15em;
  transition: color 400ms ease;
}

.paper.is-current .paper-scale {
  color: var(--accent);
}

.paper h3 {
  margin-block: var(--s-2);
  max-width: 34rem;
  font-weight: 600;
}

.paper-note {
  color: var(--fg-muted);
  max-width: 34rem;
}

.authors {
  margin-block-start: var(--s-3);
  color: var(--fg-faint);
  max-width: 34rem;
}

.authors b {
  color: var(--fg);
  font-weight: 650;
}

.sub-papers {
  margin-block-start: var(--s-4);
  border-inline-start: 1px solid var(--rule);
  padding-inline-start: var(--s-4);
  display: grid;
  gap: var(--s-3);
  max-width: 34rem;
}

.sub-papers li {
  display: grid;
  gap: 2px;
}

.sub-venue {
  color: var(--fg-faint);
  font-size: 0.72rem;
}

.paper-links {
  margin-block-start: var(--s-3);
}

.paper--quantum {
  position: relative;
}


/* ---- #03 the open system ------------------------------------------------ */

.open-system {
  position: relative;
  overflow: hidden;
  isolation: isolate;
}

.os-grid {
  display: grid;
  gap: var(--s-7);
  grid-template-columns: minmax(0, 1.15fr) minmax(0, 1fr);
  align-items: start;
}

@media (max-width: 52rem) {
  .os-grid {
    grid-template-columns: 1fr;
  }
}

.quip b {
  color: var(--accent-fg);
  font-weight: 600;
}

.abstract {
  margin: 0;
  padding: var(--s-5);
  border-inline-start: 2px solid var(--accent);
  background: color-mix(in oklab, var(--bg-raised) 55%, transparent);
  border-radius: 0 var(--r-md) var(--r-md) 0;
}

.abstract p {
  font-size: var(--fs-small);
  line-height: 1.72;
  color: var(--fg-muted);
}

.abstract footer {
  margin-block-start: var(--s-3);
  color: var(--fg-faint);
}

/* the interactive model */
.lab {
  margin: var(--s-8) 0 0;
  padding: var(--s-5);
  border: 1px solid var(--rule);
  border-radius: var(--r-lg);
  background: color-mix(in oklab, var(--bg-raised) 45%, transparent);
}

.lab-head {
  max-width: 40rem;
  margin-block-end: var(--s-5);
}

.lab-head p {
  color: var(--fg-muted);
  margin-block-start: var(--s-2);
}

.lab-plot {
  position: relative;
  border-radius: var(--r-md);
  background: var(--bg-sunk);
  overflow: hidden;
}

#lab-canvas {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 900 / 420;
  touch-action: pan-y;
}

.lab-legend {
  position: absolute;
  inset-block-start: var(--s-3);
  inset-inline-end: var(--s-4);
  display: flex;
  gap: var(--s-4);
}

.key::before {
  content: '';
  display: inline-block;
  width: 14px;
  height: 2px;
  margin-inline-end: 6px;
  vertical-align: middle;
}

.key--charger {
  color: var(--fg-muted);
}
.key--charger::before {
  background: var(--fg-muted);
}

.key--battery {
  color: var(--charge);
}
.key--battery::before {
  background: var(--charge);
}

.lab-controls {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(13rem, 1fr));
  gap: var(--s-4);
  margin-block-start: var(--s-5);
}

.ctrl {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: var(--s-2) var(--s-3);
  align-items: center;
}

.ctrl-name {
  grid-column: 1 / -1;
  color: var(--fg-muted);
}

.ctrl-name i {
  font-family: var(--font-display);
  font-style: italic;
  text-transform: none;
  letter-spacing: 0;
  font-size: 1.05em;
}

.ctrl output {
  font-size: var(--fs-small);
  color: var(--accent-fg);
  min-width: 3ch;
  text-align: right;
}

input[type='range'] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  /* Full-height target: the thumb is small, the thing you can grab is not. */
  height: 44px;
  background: none;
  cursor: grab;
  touch-action: pan-y;
}

input[type='range']:active {
  cursor: grabbing;
}

input[type='range']::-webkit-slider-runnable-track {
  height: 3px;
  border-radius: 2px;
  background: var(--rule-strong);
}

input[type='range']::-moz-range-track {
  height: 3px;
  border-radius: 2px;
  background: var(--rule-strong);
}

input[type='range']::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 22px;
  height: 22px;
  margin-block-start: -9.5px;
  border-radius: 50%;
  background: var(--fg);
  border: 5px solid var(--bg-raised);
  box-shadow: var(--shadow-sm);
  transition: transform 120ms ease-out, background-color 160ms ease;
}

input[type='range']::-moz-range-thumb {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--fg);
  border: 5px solid var(--bg-raised);
  box-shadow: var(--shadow-sm);
}

input[type='range']:active::-webkit-slider-thumb {
  transform: scale(1.18);
  background: var(--charge);
}

input[type='range']:active::-moz-range-thumb {
  background: var(--charge);
}

.lab-readout {
  margin-block-start: var(--s-4);
  font-size: var(--fs-small);
  color: var(--charge-soft);
}

.lab-caveat {
  margin-block-start: var(--s-2);
  color: var(--fg-faint);
  max-width: 40rem;
}


/* ---- #04 superposition -------------------------------------------------- */

.superposition {
  position: relative;
}

.big-quote {
  margin: 0 0 var(--s-9);
  max-width: 40rem;
}

.big-quote p {
  font-family: var(--font-display);
  font-size: clamp(1.35rem, 2.6vw, 2rem);
  line-height: 1.34;
  letter-spacing: -0.018em;
  max-width: none;
}

.big-quote p + p {
  margin-block-start: var(--s-5);
  color: var(--fg-muted);
}

.big-quote footer {
  margin-block-start: var(--s-5);
  color: var(--fg-faint);
  font-family: var(--font-mono);
  letter-spacing: 0.04em;
}

.measure-lab {
  display: grid;
  grid-template-columns: minmax(0, 20rem) minmax(0, 1fr);
  gap: var(--s-7);
  align-items: start;
}

@media (max-width: 46rem) {
  .measure-lab {
    grid-template-columns: 1fr;
  }
}

.measure-card {
  position: relative;
  aspect-ratio: 4 / 5;
  display: grid;
  place-items: center;
  padding: var(--s-5);
  border: 1px solid var(--rule-strong);
  border-radius: var(--r-xl);
  background: color-mix(in oklab, var(--bg-raised) 60%, transparent);
  overflow: hidden;
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
  -webkit-tap-highlight-color: transparent;
  touch-action: none;
  /* JS writes --squeeze while held: the state is being compressed onto an
     eigenbasis. */
  scale: calc(1 - var(--squeeze, 0) * 0.03);
}

.measure-label {
  position: absolute;
  inset-block-start: var(--s-4);
  inset-inline-start: var(--s-5);
}

.measure-hint {
  position: absolute;
  inset-block-end: var(--s-4);
  inset-inline: var(--s-5);
  text-align: center;
  color: var(--fg-faint);
  transition: opacity 260ms ease;
}

/* the superposed states, ghosted on top of each other */
.measure-stack {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  opacity: calc(1 - var(--collapsed, 0));
}

.eigen {
  grid-area: 1 / 1;
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 4vw, 2.4rem);
  letter-spacing: -0.02em;
  color: var(--fg);
  opacity: var(--amp);
  filter: blur(var(--smear, 2px));
  translate: var(--ex, 0) var(--ey, 0);
  will-change: translate, opacity;
}

.measure-result {
  grid-area: 1 / 1;
  display: grid;
  justify-items: center;
  gap: var(--s-2);
  text-align: center;
  opacity: var(--collapsed, 0);
}

.measure-result[hidden] {
  display: none;
}

.measure-word {
  font-family: var(--font-display);
  font-size: clamp(2rem, 6vw, 3.2rem);
  line-height: 1;
  letter-spacing: -0.03em;
  color: var(--accent-fg);
}

.measure-gloss {
  color: var(--fg-faint);
}

/* histogram of outcomes -- the Born rule, accumulated by hand */
.histogram {
  display: grid;
  gap: var(--s-2);
  margin-block: var(--s-5);
}

.histogram li {
  display: grid;
  grid-template-columns: 7rem 1fr 2.5rem;
  gap: var(--s-3);
  align-items: center;
  font-size: var(--fs-small);
}

.histo-bar {
  position: relative;
  height: 8px;
  border-radius: 4px;
  background: color-mix(in oklab, var(--fg) 10%, transparent);
  overflow: hidden;
}

.histo-bar span {
  position: absolute;
  inset: 0;
  transform-origin: left center;
  transform: scaleX(var(--p, 0));
  background: var(--accent);
  border-radius: 4px;
}

.histo-count {
  text-align: right;
  color: var(--fg-faint);
  font-family: var(--font-mono);
  font-size: 0.72rem;
}

.measure-count {
  margin-block-end: var(--s-4);
}

.measure-stats > .small {
  color: var(--fg-muted);
}


/* ---- #05 boarding passes ------------------------------------------------ */

.passes {
  overflow: hidden;
  --pass-w: min(30rem, 82vw);
}

.deck {
  margin-block-start: var(--s-7);
  /* Vertical panning still belongs to the page; we only claim horizontal. */
  touch-action: pan-y;
  cursor: grab;
}

.deck:active {
  cursor: grabbing;
}

.deck-track {
  display: flex;
  gap: var(--s-5);
  padding-inline: var(--gutter);
  will-change: transform;
}

.pass {
  flex: 0 0 auto;
  width: var(--pass-w);
  /* JS writes these: the card leans toward the pointer and lifts on hover. */
  transform: perspective(1200px) rotateX(var(--rx, 0deg)) rotateY(var(--ry, 0deg))
    translateZ(var(--tz, 0px));
  transform-style: preserve-3d;
}

.pass-face {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 4.5rem;
  min-height: 17rem;
  border-radius: var(--r-lg);
  overflow: hidden;
  background: var(--paper);
  color: var(--ink);
  box-shadow: var(--shadow-md);
  isolation: isolate;
}

/* Gold foil: a specular highlight that tracks the pointer across the card. */
.pass-face::after {
  content: '';
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: radial-gradient(
    26rem 26rem at var(--sx, 50%) var(--sy, 0%),
    color-mix(in oklab, #fff 46%, transparent),
    transparent 62%
  );
  opacity: var(--sheen, 0);
  mix-blend-mode: soft-light;
  transition: opacity 320ms ease;
}

/* His own artwork, both sides, the way he posted it. */
.pass-face--image {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--s-3);
  min-height: 0;
  background: none;
  box-shadow: none;
  border-radius: 0;
  overflow: visible;
}

.pass-face--image::after {
  content: none;
}

.pass-face--image img {
  width: 100%;
  height: auto;
  border-radius: var(--r-md);
  box-shadow: var(--shadow-md);
}

.pass-main {
  padding: var(--s-5);
  display: flex;
  flex-direction: column;
  gap: var(--s-3);
}

.pass-kicker {
  color: color-mix(in oklab, var(--ink) 55%, transparent);
}

.pass-route {
  display: flex;
  align-items: center;
  gap: var(--s-4);
}

.pass-code {
  font-size: clamp(1.9rem, 5vw, 2.6rem);
  font-weight: 700;
  letter-spacing: -0.01em;
}

.pass-code--unknown {
  color: var(--gold);
  filter: blur(0.7px);
}

.pass-arrow {
  flex: 1;
  height: 1px;
  background: repeating-linear-gradient(
    to right,
    color-mix(in oklab, var(--ink) 40%, transparent) 0 4px,
    transparent 4px 8px
  );
  position: relative;
}

.pass-arrow::after {
  content: '';
  position: absolute;
  inset-inline-end: -1px;
  inset-block-start: 50%;
  width: 8px;
  height: 8px;
  margin-block-start: -4px;
  background: var(--gold);
  clip-path: polygon(0 0, 100% 50%, 0 100%, 22% 50%);
}

.pass-title {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.22;
}

.pass-fields {
  display: grid;
  gap: var(--s-3);
  margin: 0;
  font-size: var(--fs-small);
}

.pass-fields > div {
  display: grid;
  gap: 1px;
}

.pass-fields dt {
  color: color-mix(in oklab, var(--ink) 52%, transparent);
}

.pass-fields dd {
  margin: 0;
  font-weight: 550;
  line-height: 1.4;
}

.pass-quip {
  color: var(--gold);
  font-weight: 550;
}

.pass-stub {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between;
  gap: var(--s-3);
  padding: var(--s-4) var(--s-2);
  background: color-mix(in oklab, var(--ink) 92%, transparent);
  color: var(--paper);
  /* The perforation. */
  border-inline-start: 2px dashed color-mix(in oklab, var(--paper) 45%, transparent);
}

.pass-stub .label {
  color: color-mix(in oklab, var(--paper) 78%, transparent);
  writing-mode: vertical-rl;
  rotate: 180deg;
}

.pass-barcode {
  width: 100%;
  flex: 1;
  min-height: 5rem;
  background: repeating-linear-gradient(
    to bottom,
    var(--paper) 0 2px,
    transparent 2px 4px,
    var(--paper) 4px 5px,
    transparent 5px 9px,
    var(--paper) 9px 12px,
    transparent 12px 14px
  );
  opacity: 0.85;
}

.pass-barcode--fuzzy {
  filter: blur(1.4px);
  opacity: 0.5;
}

.status-boarding {
  color: var(--gold);
  font-weight: 700;
}

.pass-caption {
  margin-block-start: var(--s-3);
  color: var(--fg-faint);
}

.pass--open .pass-face {
  background: repeating-linear-gradient(
      135deg,
      var(--paper) 0 12px,
      color-mix(in oklab, var(--paper) 92%, var(--gold)) 12px 24px
    );
}

.deck-ui {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--s-4);
  margin-block-start: var(--s-5);
}

.deck-dots {
  display: flex;
  /* No gap: each dot carries its own hit area, and the areas should touch. */
  gap: 0;
  margin-inline-start: -5px;
}

/* The dot you see is 8px; the target you press is 44px tall. */
.deck-dot {
  display: grid;
  place-items: center;
  width: 26px;
  height: 44px;
  border-radius: var(--r-sm);
}

.deck-dot::before {
  content: '';
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--rule-strong);
  transition: background-color 260ms ease,
    scale 260ms cubic-bezier(0.2, 0.8, 0.2, 1);
}

.deck-dot[aria-current='true']::before {
  background: var(--accent);
  scale: 1.4;
}

@media (hover: hover) and (pointer: fine) {
  .deck-dot:hover::before {
    background: var(--fg-muted);
  }
}

.deck-hint {
  color: var(--fg-faint);
}


/* ---- #06 power set ------------------------------------------------------ */

.plate {
  display: grid;
  grid-template-columns: minmax(0, 15rem) minmax(0, 1fr);
  gap: var(--s-7);
  align-items: start;
  padding: var(--s-6);
  border: 1px solid var(--rule);
  border-radius: var(--r-xl);
  background: color-mix(in oklab, var(--bg-raised) 55%, transparent);
  position: relative;
  overflow: hidden;
}

/* the plate gets the foil too */
.plate::after {
  content: '';
  position: absolute;
  inset: 0;
  pointer-events: none;
  background: radial-gradient(
    30rem 30rem at var(--sx, 50%) var(--sy, 0%),
    color-mix(in oklab, var(--gold) 26%, transparent),
    transparent 60%
  );
  opacity: var(--sheen, 0);
  transition: opacity 380ms ease;
}

@media (max-width: 46rem) {
  .plate {
    grid-template-columns: 1fr;
    padding: var(--s-5);
  }
}

.plate-portrait img {
  width: 100%;
  border-radius: var(--r-lg);
  box-shadow: var(--shadow-md);
}

.plate-alias {
  margin-block: var(--s-2) var(--s-5);
  color: var(--accent-fg);
}

.status-list {
  display: grid;
  gap: var(--s-2);
  margin-block-end: var(--s-6);
  font-size: var(--fs-small);
}

.status-list li {
  display: flex;
  gap: var(--s-3);
  align-items: baseline;
}

.status-list span {
  color: var(--fg-muted);
  min-width: 9rem;
}

.status-list .ok {
  color: var(--charge);
}

.plate-cols {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(13rem, 1fr));
  gap: var(--s-6);
  margin-block-end: var(--s-6);
}

.record {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-6);
  margin: 0;
  padding-block-start: var(--s-5);
  border-block-start: 1px solid var(--rule);
}

.record > div {
  display: grid;
  gap: 2px;
}

.record dd {
  margin: 0;
  font-size: 1.9rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1;
  color: var(--accent-fg);
}


/* ---- colophon ----------------------------------------------------------- */

.colophon {
  padding-block: var(--s-8);
  border-block-start: 1px solid var(--rule);
  background: var(--bg-sunk);
}

.colophon-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr));
  gap: var(--s-6);
}

.colophon-grid .label {
  margin-block-end: var(--s-3);
}

.colophon-grid .small {
  color: var(--fg-muted);
}

.colophon-note {
  margin-block-start: var(--s-2);
  color: var(--fg-faint);
}

.colophon-foot {
  margin-block-start: var(--s-8);
  padding-block-start: var(--s-5);
  border-block-start: 1px solid var(--rule);
  color: var(--fg-faint);
  font-size: 0.72rem;
  letter-spacing: 0.03em;
}