:root {
  --bg-dark: #000;
  --fg-dark: #f5f5f7;
  --muted-dark: #86868b;
  --bg-light: #f5f5f7;
  --fg-light: #1d1d1f;
  --muted-light: #6e6e73;
  --accent: #23e6ff;
  --maxw: 1040px;
  --copyw: 560px;
  --gutter: 48px;
  --bar-h: 56px;
  --ease: cubic-bezier(0.25, 0.1, 0.25, 1);
  --fs-hero: 112px;
  --fs-head: 72px;
  --fs-copy: 26px;
  --fs-fig: 70px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  background: var(--bg-dark);
}

body {
  margin: 0;
  background: var(--bg-dark);
  color: var(--fg-dark);
  font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
  font-size: 21px;
  line-height: 1.5;
  letter-spacing: -0.003em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

body.is-locked {
  overflow: hidden;
}

[hidden] {
  display: none !important;
}

::selection {
  background: rgba(35, 230, 255, 0.3);
}

a {
  color: inherit;
  text-decoration: none;
}

img,
video {
  display: block;
  max-width: 100%;
}

a:focus-visible,
button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

main {
  position: relative;
}

/* Sticky frosted bar ------------------------------------------------------ */

.bar {
  position: fixed;
  inset: 0 0 auto;
  z-index: 100;
  height: var(--bar-h);
  background: rgba(0, 0, 0, 0.66);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  backdrop-filter: saturate(180%) blur(20px);
  color: var(--fg-dark);
  transition: background-color 0.4s var(--ease), color 0.4s var(--ease);
}

.bar.is-light {
  background: rgba(245, 245, 247, 0.7);
  color: var(--fg-light);
}

.bar-inner {
  height: 100%;
  padding-inline: 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.bar-brand {
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.pill {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--accent);
  color: #000;  /* black on cyan reads better (human, 2026-10-28) */
  border-radius: 980px;
  font-weight: 600;
  line-height: 1;
  letter-spacing: -0.01em;
  transition: filter 0.25s var(--ease), transform 0.25s var(--ease);
}

.pill:hover {
  filter: brightness(1.08);
}

.pill:active {
  transform: scale(0.98);
}

.pill--small {
  font-size: 13px;
  padding: 7px 17px;
}

.pill--large {
  margin-top: 44px;
  font-size: 21px;
  padding: 18px 52px;
}

/* Hero -------------------------------------------------------------------- */

.hero {
  position: relative;
  height: 100vh;
  min-height: 720px;
  background: var(--bg-dark);
  overflow: hidden;
}

#hero-stage {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.hero-copy {
  position: relative;
  z-index: 1;
  padding: calc(var(--bar-h) + 6vh) var(--gutter) 0;
  text-align: center;
  pointer-events: none;
}

.hero-title {
  margin: 0;
  font-size: var(--fs-hero);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.025em;
}

.hero-sub {
  margin: 14px 0 0;
  font-size: 30px;
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.015em;
  color: var(--muted-dark);
}

.hero-authors {
  margin: 34px 0 0;
  font-size: 16px;
  line-height: 1.6;
  color: var(--muted-dark);
}

.hero-authors a {
  color: var(--fg-dark);
  transition: color 0.25s var(--ease);
  pointer-events: auto;
}

.hero-authors a:hover {
  color: var(--accent);
}

.hero-affil {
  margin: 2px 0 0;
  font-size: 16px;
  line-height: 1.6;
  color: var(--muted-dark);
}

.hero-copy .pill--large {
  pointer-events: auto;
}

/* Shared type ------------------------------------------------------------- */

.copy {
  margin: 0;
  font-size: var(--fs-copy);
  line-height: 1.42;
  letter-spacing: -0.011em;
  max-width: var(--copyw);
}

.copy--narrow {
  max-width: 460px;
  font-size: 23px;
}


/* Fades: one gradient per element, so a photo can dissolve on all four edges
   without mask compositing. Put fade-x on the frame and fade-y on the media. */

.fade-x {
  -webkit-mask-image: linear-gradient(to right, transparent 0%, #000 16%, #000 84%, transparent 100%);
  mask-image: linear-gradient(to right, transparent 0%, #000 16%, #000 84%, transparent 100%);
}

.fade-y {
  -webkit-mask-image: linear-gradient(to bottom, transparent 0%, #000 14%, #000 86%, transparent 100%);
  mask-image: linear-gradient(to bottom, transparent 0%, #000 14%, #000 86%, transparent 100%);
}

/* A wider fade for stills that must melt into the section colour. */

.fade-soft-x {
  -webkit-mask-image: linear-gradient(to right, transparent 0%, #000 26%, #000 74%, transparent 100%);
  mask-image: linear-gradient(to right, transparent 0%, #000 26%, #000 74%, transparent 100%);
}

.fade-soft-y {
  -webkit-mask-image: linear-gradient(to bottom, transparent 0%, #000 22%, #000 78%, transparent 100%);
  mask-image: linear-gradient(to bottom, transparent 0%, #000 22%, #000 78%, transparent 100%);
}

/* Long colour transitions between sections -------------------------------- */

/* Each tone is a smoothstep ramp sampled in 17 steps: both ends leave and
   arrive slowly, so the dissolve has no band and no kink (human, 2026-10-28).
   sec-page.css sets every tone's height; this file owns the two ramps. */

.tone {
  height: 58vh;
  pointer-events: none;
}

.tone--dark-to-light {
  background: linear-gradient(
    180deg,
    #000000 0%,
    #030303 1.12305%,
    #0b0b0b 4.29688%,
    #171717 9.22852%,
    #262627 15.625%,
    #393939 23.1934%,
    #4e4e4e 31.6406%,
    #646464 40.6738%,
    #7a7a7c 50%,
    #919193 59.3262%,
    #a7a7a9 68.3594%,
    #bcbcbe 76.8066%,
    #cfcfd0 84.375%,
    #dedee0 90.7715%,
    #eaeaec 95.7031%,
    #f2f2f4 98.877%,
    #f5f5f7 100%
  );
}

.tone--light-to-dark {
  background: linear-gradient(
    180deg,
    #f5f5f7 0%,
    #f2f2f4 1.12305%,
    #eaeaec 4.29688%,
    #dedee0 9.22852%,
    #cfcfd0 15.625%,
    #bcbcbe 23.1934%,
    #a7a7a9 31.6406%,
    #919193 40.6738%,
    #7a7a7c 50%,
    #646464 59.3262%,
    #4e4e4e 68.3594%,
    #393939 76.8066%,
    #262627 84.375%,
    #171717 90.7715%,
    #0b0b0b 95.7031%,
    #030303 98.877%,
    #000000 100%
  );
}

/* Film -------------------------------------------------------------------- */

.film {
  background: var(--bg-dark);
  padding: 4vh 0 10vh;
}

.film-still {
  position: relative;
  width: min(1320px, calc(100% - var(--gutter) * 2));
  margin-inline: auto;
  aspect-ratio: 21 / 9;
  cursor: pointer;
}

.film-frame {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: 50% 100%;
  filter: brightness(0.62) contrast(1.05) saturate(0.95);
  opacity: 0;
  transition: opacity 0.8s var(--ease);
}

.film-still.is-ready .film-frame {
  opacity: 1;
}

.film-play {
  position: absolute;
  left: 50%;
  top: 50%;
  width: 96px;
  height: 96px;
  margin: -48px 0 0 -48px;
  padding: 0;
  border: 0;
  border-radius: 50%;
  background: rgba(245, 245, 247, 0.16);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  cursor: pointer;
  transition: background-color 0.3s var(--ease), transform 0.3s var(--ease);
}

.film-play:hover {
  background: rgba(245, 245, 247, 0.28);
  transform: scale(1.04);
}

.film-play__icon {
  position: absolute;
  left: 50%;
  top: 50%;
  width: 0;
  height: 0;
  margin: -17px 0 0 -10px;
  border-style: solid;
  border-width: 17px 0 17px 28px;
  border-color: transparent transparent transparent #f5f5f7;
}

/* Perch ------------------------------------------------------------------- */

.perch {
  height: 280vh;
  background: var(--bg-light);
  color: var(--fg-light);
}

.perch-pin {
  position: sticky;
  top: 0;
  height: 100vh;
  display: grid;
  grid-template-columns: minmax(0, 1.12fr) minmax(360px, 0.88fr);
  align-items: center;
  gap: 3vw;
  padding: 0 6vw;
}

.perch.is-empty {
  height: auto;
  padding: 14vh 0 6vh;
}

.perch.is-empty .perch-pin {
  position: static;
  height: auto;
  grid-template-columns: 1fr;
}

.perch.is-empty .perch-media {
  display: none;
}

.perch-media {
  position: relative;
  height: 78vh;
}

.perch-media canvas {
  width: 100%;
  height: 100%;
  mix-blend-mode: multiply;
}

.perch-copy {
  padding-bottom: 4vh;
}

/* Mounts ------------------------------------------------------------------ */

.mounts {
  height: 380vh;
  background: var(--bg-light);
  color: var(--fg-light);
}

.mounts-pin {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow: hidden;
}

#mounts-stage {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.mounts-copy {
  position: absolute;
  left: 6vw;
  bottom: 11vh;
  z-index: 3;
  display: flex;
  flex-direction: column;
  gap: 22px;
  width: min(520px, 38vw);
  pointer-events: none;
}

.mounts-copy .copy {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.9s var(--ease), transform 0.9s var(--ease);
}

.mounts-copy .copy.is-on {
  opacity: 1;
  transform: none;
}

/* Inside the sensor ------------------------------------------------------- */

.inside {
  height: 340vh;
  background: var(--bg-dark);
  color: var(--fg-dark);
}

.inside-pin {
  position: sticky;
  top: 0;
  height: 100vh;
  overflow: hidden;
}

#inside-stage {
  position: absolute;
  inset: 0;
  z-index: 0;
}

.inside-copy {
  position: absolute;
  left: 6vw;
  top: 15vh;
  z-index: 3;
  width: min(380px, 27vw);
  pointer-events: none;
}

.inside-copy .copy {
  font-size: 21px;
  line-height: 1.42;
}

.inside-copy .copy {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.9s var(--ease), transform 0.9s var(--ease);
}

.inside-copy .copy.is-on {
  opacity: 1;
  transform: none;
}

/* Numbers ----------------------------------------------------------------- */

.numbers {
  background: var(--bg-dark);
  color: var(--fg-dark);
  padding: 24vh 6vw 22vh;
}

.numbers-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10vh 3vw;
  align-items: end;
  max-width: 1400px;
  margin-inline: auto;
}

.stat--mass {
  grid-area: 1 / 1;
}

.stat--price {
  grid-area: 1 / 2;
}

.stat--life {
  grid-area: 1 / 3;
}

.stat--dims {
  grid-area: 2 / 1 / 3 / -1;
}

.stat--force {
  grid-area: 3 / 1;
}

.stat--latency {
  grid-area: 3 / 2;
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.stat-figure {
  font-size: var(--fs-fig);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.025em;
  white-space: nowrap;
}

.stat-figure--sub {
  color: var(--muted-dark);
}

/* Surfaces ---------------------------------------------------------------- */

.surfaces {
  height: 240vh;
  background: var(--bg-light);
  color: var(--fg-light);
}

.surfaces.is-empty {
  height: auto;
  padding: 12vh 0;
}

.surfaces.is-empty .surf-pin {
  position: static;
  height: auto;
}

.surf-pin {
  position: sticky;
  top: 0;
  height: 100vh;
  display: flex;
  align-items: center;
  overflow: hidden;
}

.surf-track {
  display: flex;
  align-items: center;
  gap: 4vw;
  padding-inline: 8vw;
  will-change: transform;
}

.surfaces.is-empty .surf-track {
  padding-inline: 0;
}

.surf-item {
  flex: 0 0 auto;
  width: min(42vw, 620px);
  margin: 0;
}

.surf-frame,
.sensing-item > div {
  display: block;
}

.surf-item img {
  width: 100%;
  height: 52vh;
  object-fit: cover;
  mix-blend-mode: multiply;
}

.surf-item figcaption {
  margin-top: 14px;
  padding-left: 2px;
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.01em;
  color: var(--muted-light);
}

.surf-item.is-missing {
  display: none;
}

/* Sensing modalities ------------------------------------------------------ */

.sensing {
  background: var(--bg-light);
  color: var(--fg-light);
  padding: 8vh 6vw 20vh;
}

.sensing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 5vh 4vw;
  align-items: center;
  max-width: 1080px;
  margin-inline: auto;
}

.sensing-item {
  margin: 0;
}

.sensing-item img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  mix-blend-mode: multiply;
}

.sensing-item.is-missing {
  display: none;
}

.sensing.is-empty {
  padding-block: 12vh;
}

.sensing.is-empty .sensing-grid {
  display: none;
}

.sensing-caption {
  max-width: 760px;
  margin: 12vh auto 0;
  font-size: 24px;
  line-height: 1.4;
  letter-spacing: -0.011em;
  text-align: center;
  color: var(--muted-light);
}

/* Results ----------------------------------------------------------------- */

.results {
  background: var(--bg-dark);
  color: var(--fg-dark);
  padding: 20vh 6vw 24vh;
  display: grid;
  gap: 20vh;
  max-width: 1400px;
  margin-inline: auto;
}

.result {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 0 6vw;
  align-items: center;
}

.result-figure {
  font-size: clamp(120px, 13vw, 210px);
  font-weight: 700;
  line-height: 0.9;
  letter-spacing: -0.04em;
}

.result .copy {
  color: var(--fg-dark);
  align-self: center;
  margin-top: 24px;
}

.result .copy.copy--narrow {
  max-width: 480px;
  font-size: 22px;
  color: #a1a1a6;
}

/* Abstract ---------------------------------------------------------------- */

.abstract {
  background: var(--bg-light);
  color: var(--fg-light);
  padding: 18vh 6vw 16vh;
}

.abstract-copy {
  max-width: 980px;
  margin-inline: auto;
  font-size: 27px;
  line-height: 1.46;
  letter-spacing: -0.012em;
}

/* BibTeX ------------------------------------------------------------------ */

.bibtex {
  background: var(--bg-light);
  color: var(--fg-light);
  padding: 6vh 6vw 14vh;
}

.bibtex-inner {
  max-width: 860px;
  margin-inline: auto;
}

.bibtex-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 22px;
}

.bibtex-title {
  margin: 0;
  font-size: 26px;
  font-weight: 700;
  letter-spacing: -0.02em;
}

.bibtex-code {
  margin: 0;
  overflow-x: auto;
  font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  font-size: 14px;
  line-height: 1.75;
  color: var(--fg-light);
  letter-spacing: 0;
  opacity: 0.8;
}

.copy-button {
  padding: 9px 20px;
  border: 0;
  border-radius: 980px;
  background: var(--fg-light);
  color: #fff;
  font: inherit;
  font-size: 13px;
  font-weight: 600;
  line-height: 1;
  cursor: pointer;
  transition: background-color 0.25s var(--ease), transform 0.25s var(--ease);
}

.copy-button:hover {
  background: #000;
}

.copy-button:active {
  transform: scale(0.98);
}

.copy-button.is-copied {
  background: var(--accent);
}

/* Footer ------------------------------------------------------------------ */

.footer {
  background: var(--bg-light);
  color: var(--muted-light);
  padding: 30px 0 90px;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
  text-align: center;
}

.footer-logo {
  height: 40px;
  width: auto;
  filter: grayscale(1);
  opacity: 0.7;
}

.footer-text {
  margin: 0;
  font-size: 13px;
  line-height: 1.5;
  letter-spacing: 0;
}

.footer-text a {
  color: var(--muted-light);
  text-decoration: underline;
  text-decoration-color: rgba(110, 110, 115, 0.4);
  text-underline-offset: 2px;
  transition: color 0.25s var(--ease);
}

.footer-text a:hover {
  color: var(--fg-light);
}

/* Overlays ---------------------------------------------------------------- */

.overlay {
  position: fixed;
  inset: 0;
  z-index: 200;
  background: #000;
  opacity: 0;
  transition: opacity 0.4s var(--ease);
}

.overlay.is-open {
  opacity: 1;
}

.overlay-close {
  position: absolute;
  top: 20px;
  right: 28px;
  z-index: 4;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 0;
  border-radius: 50%;
  background: transparent;
  color: var(--fg-dark);
  font-family: inherit;
  font-size: 30px;
  font-weight: 300;
  line-height: 1;
  cursor: pointer;
  opacity: 0.6;
  transition: opacity 0.25s var(--ease);
}

.overlay-close:hover {
  opacity: 1;
}

.film-video {
  position: absolute;
  inset: 0;
  margin: auto;
  width: min(100vw, calc(100vh * 16 / 9));
  max-height: 100vh;
  background: #000;
}

.layer-stage {
  position: absolute;
  inset: 0;
}

.layer-labels {
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.layer-copy {
  position: absolute;
  left: 6vw;
  bottom: 10vh;
  z-index: 3;
  max-width: 420px;
  font-size: 21px;
  color: var(--fg-dark);
}

.layer-copy span {
  display: none;
}

.layer-copy span.is-on {
  display: block;
}

/* Layer child labels: text with a fine line, no box ----------------------- */

.layer-label {
  position: absolute;
  left: 0;
  top: 0;
  z-index: 2;
  transform: translateY(-50%);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--fg-dark);
  white-space: nowrap;
  opacity: 0;
  transition: opacity 0.5s var(--ease);
}

.layer-label.is-on {
  opacity: 1;
}

.layer-label--group {
  font-size: 19px;
  color: #fff;
}

/* Reveal on scroll -------------------------------------------------------- */

.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.9s var(--ease), transform 0.9s var(--ease);
}

.reveal.in {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .reveal,
  .mounts-copy .copy,
  .inside-copy .copy {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .bar,
  .pill,
  .copy-button,
  .hero-authors a,
  .film-play,
  .layer-label {
    transition: none;
  }
}

/* Narrower desktop windows ------------------------------------------------ */

@media (max-width: 1280px) {
  :root {
    --fs-hero: 92px;
    --fs-head: 60px;
    --fs-copy: 24px;
    --fs-fig: 64px;
  }

  .hero-sub {
    font-size: 26px;
  }
}