/* RopeFormer project page */
@font-face {
  font-family: 'DejaVu Sans Mono';
  src: url('../fonts/DejaVuSansMono-Bold.woff2') format('woff2');
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: 'LM Mono';
  src: url('../fonts/lmmono10-regular.woff2') format('woff2');
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

:root {
  --bg: #0b0b0c;
  --fg: #f4f2ee;
  --muted: #b9b3a8;
  --accent: #ff8a4c;
  --accent-ink: #1a0d05;
  --paper: #faf9f5;
  --paper-2: #f2efe8;
  --line: #e3ded4;
  --ink: #141413;
  --ink-2: #2b2925;
  --ink-3: #5f5a52;
  --ink-4: #7a7368;
  --gut: clamp(16px,4vw,56px);
  --bar: 72px;
  --col: 760px;
  --wide: 1200px;
  --rail: 220px;
  --sans: 'IBM Plex Sans',system-ui,-apple-system,'Segoe UI',sans-serif;
  --display: 'Manrope',var(--sans);
  --tt: 'LM Mono','Latin Modern Mono',ui-monospace,Menlo,Consolas,monospace;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--bar) + 28px);
}

html.locked {
  overflow: hidden;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: inherit;
}

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

sup {
  font-size: .6em;
  line-height: 0;
}

.tt {
  font-family: var(--tt);
  font-size: 1.04em;
  letter-spacing: 0;
}

/* ---------- hero stage ---------- */
.hero {
  position: fixed;
  inset: 0;
  z-index: 20;
  color: var(--fg);
  overflow: hidden;
}

.hero.closed {
  pointer-events: none;
}

.hero .bg {
  position: absolute;
  inset: 0;
  background: var(--bg);
}

.hero .bg img,.hero .bg video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: 60% 18%;
}

.hero .bg .shade {
  position: absolute;
  inset: 0;
  background: linear-gradient(180deg,rgba(0,0,0,.15),rgba(0,0,0,.35) 45%,rgba(0,0,0,.84));
}

.stack {
  position: absolute;
  left: var(--gut);
  right: var(--gut);
  bottom: 56px;
  display: flex;
  flex-direction: column;
  gap: 22px;
  max-width: 1040px;
}

.markbox {
  height: calc(clamp(64px,12.5vw,180px)*1.12);
}

.mark {
  font-family: var(--display);
  font-weight: 800;
  font-size: clamp(64px,12.5vw,180px);
  line-height: .9;
  letter-spacing: -.05em;
  color: var(--accent);
  display: flex;
  width: max-content;
  white-space: nowrap;
  transform-origin: 0 0;
  will-change: transform;
  cursor: pointer;
}

.mark .l {
  display: inline-block;
  opacity: 0;
  filter: blur(14px);
  transform: translateY(.35em) scale(.96);
}

.play .mark .l {
  animation: emerge .9s cubic-bezier(.2,.7,.2,1) forwards;
  animation-delay: calc(var(--i)*.07s);
}

@keyframes emerge {
  60% {
    filter: blur(0);
  }
  to {
    opacity: 1;
    filter: blur(0);
    transform: none;
  }
}

.t {
  opacity: 0;
  will-change: opacity,transform;
}

.hero h1 {
  margin: 0;
  font-family: var(--display);
  font-weight: 500;
  font-size: clamp(22px,2.8vw,40px);
  line-height: 1.2;
  letter-spacing: -.015em;
  max-width: 980px;
  text-wrap: balance;
}

.authors {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 22px;
  font-size: 18px;
  color: #e6e2da;
}

.authors a {
  text-decoration: none;
  border-bottom: 1px solid rgba(230,226,218,.35);
}

.authors a:hover {
  border-color: #e6e2da;
}

.affil {
  font-size: 15px;
  color: var(--muted);
  line-height: 1.6;
}

.ctabox {
  height: 44px;
}

.cta {
  width: max-content;
  max-width: calc(100vw - 2 * var(--gut));
  transform-origin: 0 0;
  will-change: transform;
}

.ctain {
  display: flex;
  gap: 10px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  height: 44px;
  padding: 0 18px;
  border-radius: 999px;
  border: 1px solid rgba(244,242,238,.4);
  background: rgba(11,11,12,.35);
  backdrop-filter: blur(6px);
  color: var(--fg);
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  font-family: var(--sans);
}

.btn:hover,.btn:focus-visible {
  border-color: var(--fg);
  outline: none;
}

.btn.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-ink);
}

.btn.primary:hover {
  background: #ffa06b;
}

.btn.soon {
  opacity: .55;
  cursor: default;
}

.btn .tag {
  font-family: var(--sans);
  font-weight: 600;
  font-size: 10px;
  letter-spacing: .1em;
  padding: 2px 6px;
  border: 1px solid currentColor;
  border-radius: 999px;
  opacity: .8;
}

.hint {
  position: absolute;
  right: var(--gut);
  bottom: 64px;
  font-family: var(--sans);
  font-weight: 600;
  font-size: 12px;
  letter-spacing: .16em;
  color: var(--muted);
  background: none;
  border: 0;
  cursor: pointer;
  padding: 8px 0;
}

.pinned {
  position: fixed;
  left: 0;
  top: 0;
  z-index: 31;
  pointer-events: auto;
}

/* ---------- top bar ---------- */
.topbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--bar);
  padding-top: env(safe-area-inset-top,0px);
  z-index: 10;
  pointer-events: none;
  background: rgba(11,11,12,.8);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(244,242,238,.12);
  opacity: 0;
  color: var(--fg);
}

.topbar.on {
  pointer-events: auto;
}

.slotL {
  position: absolute;
  left: var(--gut);
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--display);
  font-weight: 800;
  font-size: 24px;
  letter-spacing: -.05em;
  line-height: .9;
  visibility: hidden;
  white-space: nowrap;
}

.slotR {
  position: absolute;
  right: var(--gut);
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  gap: 8px;
  visibility: hidden;
}

.slotR .btn {
  height: 36px;
  padding: 0 14px;
  font-size: 14px;
}

.secnav {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%,-50%);
  display: flex;
  gap: 4px;
  opacity: 0;
}

.secnav a {
  font-size: 15px;
  font-weight: 500;
  color: #cfc9be;
  text-decoration: none;
  padding: 8px 12px;
  border-radius: 999px;
  white-space: nowrap;
}

.secnav a:hover {
  color: var(--fg);
}

.secnav a.on {
  color: var(--fg);
  background: rgba(244,242,238,.12);
}

/* ---------- body ---------- */
main {
  padding: calc(var(--bar) + 88px) var(--gut) 0;
}

section.s,.band>.s {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 0 0 120px;
  display: grid;
  grid-template-columns: var(--rail) minmax(0,1fr);
  gap: 0 48px;
  align-items: start;
}

.rail {
  position: sticky;
  top: calc(var(--bar) + 28px);
}

.lbl {
  margin: 0;
  font-family: var(--display);
  font-weight: 800;
  font-size: 30px;
  letter-spacing: -.035em;
  line-height: 1;
  color: var(--ink);
  display: flex;
  flex-wrap: wrap;
}

.lbl .l {
  display: inline-block;
  opacity: 0;
  filter: blur(8px);
  transform: translateY(.3em);
}

.lbl .l.sp {
  width: .28em;
}

.lbl.play .l {
  animation: emerge .7s cubic-bezier(.2,.7,.2,1) forwards;
  animation-delay: calc(var(--i)*.05s);
}

.body {
  min-width: 0;
  max-width: 900px;
}

.head {
  max-width: var(--col);
}

h3.hl {
  margin: 0 0 18px;
  font-family: var(--display);
  font-weight: 700;
  font-size: clamp(21px,2.1vw,26px);
  letter-spacing: -.02em;
  line-height: 1.25;
  text-wrap: balance;
}

h3 {
  margin: 36px 0 10px;
  font-family: var(--display);
  font-weight: 700;
  font-size: 21px;
  letter-spacing: -.015em;
  line-height: 1.25;
}

p {
  margin: 0 0 18px;
  font-size: 19px;
  line-height: 1.6;
  color: var(--ink-2);
}

p.small,.cap {
  font-size: 15px;
  line-height: 1.55;
  color: var(--ink-3);
}

.cap {
  margin: 12px 0 0;
}

.cap b {
  color: var(--ink-2);
  font-weight: 600;
}

.q {
  font-family: var(--display);
  font-weight: 500;
  font-size: clamp(20px,2vw,26px);
  line-height: 1.35;
  letter-spacing: -.01em;
  color: var(--ink);
  border-left: 3px solid var(--accent);
  padding-left: 20px;
  margin: 28px 0;
}

.fig {
  margin: 32px 0 0;
}

.fig img {
  width: 100%;
  height: auto;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
}

.fig.plain img {
  border: 0;
  background: transparent;
}

.grid3 {
  display: grid;
  grid-template-columns: repeat(3,minmax(0,1fr));
  gap: 32px;
  margin-top: 28px;
}

.grid3 h4 {
  margin: 0 0 8px;
  font-family: var(--display);
  font-weight: 700;
  font-size: 18px;
  letter-spacing: -.01em;
  color: var(--ink);
}

.grid3 h4 .tt {
  color: #b4531f;
  font-weight: 700;
}

.grid3 p {
  font-size: 15.5px;
  line-height: 1.55;
  color: var(--ink-3);
  margin: 0;
}

.stats {
  display: grid;
  grid-template-columns: repeat(3,minmax(0,1fr));
  gap: 32px;
  margin-top: 36px;
}

.stats .n {
  font-family: var(--display);
  font-weight: 800;
  font-size: clamp(34px,3.6vw,48px);
  letter-spacing: -.03em;
  line-height: 1;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}

.stats .n small {
  font-size: .5em;
  font-weight: 600;
  color: var(--ink-3);
  letter-spacing: 0;
}

.stats .d {
  font-size: 15px;
  color: var(--ink-3);
  margin-top: 8px;
  line-height: 1.5;
}

.video {
  position: relative;
  aspect-ratio: 16/9;
  background: #0b0b0c;
  border-radius: 10px;
  overflow: hidden;
}

.video video {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.task .video {
  background: #F5F5F5;
  border: 1px solid var(--line);
}

/* the re-rendered clips are light, same page colour as the paper renders */
.ph {
  aspect-ratio: 16/9;
  border: 1px dashed #c9c2b5;
  border-radius: 10px;
  display: grid;
  place-items: center;
  color: var(--ink-3);
  font-family: var(--sans);
  font-weight: 600;
  font-size: 13px;
  letter-spacing: .1em;
  text-transform: uppercase;
  text-align: center;
  padding: 24px;
}

.band {
  background: var(--bg);
  color: var(--fg);
  margin: 0 calc(-1*var(--gut));
  padding: 96px var(--gut) 0;
}

.band>.s {
  padding-bottom: 104px;
}

#sim {
  padding-top: 96px;
}

.band .hl,.band h3,.band .lbl {
  color: var(--fg);
}

.band p {
  color: #d8d3ca;
}

.band .cap {
  color: #a39c90;
}

.band .fig img {
  border: 0;
}

.band .q {
  border-color: var(--accent);
  color: var(--fg);
}

.band .grid3 p {
  color: #b9b3a8;
}

.band .grid3 h4 {
  color: var(--fg);
}

.band .grid3 h4 .tt {
  color: var(--accent);
}

footer {
  border-top: 1px solid var(--line);
  padding: 40px var(--gut) 56px;
  font-size: 14px;
  color: var(--ink-3);
}

footer .in {
  max-width: var(--wide);
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px 32px;
}

footer a {
  color: var(--ink-2);
}

/* reveal on scroll (JS adds .js to html) */
html.js .rv {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity .6s cubic-bezier(.2,.7,.2,1),transform .6s cubic-bezier(.2,.7,.2,1);
}

html.js .rv.in {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion:reduce) {
  .l {
    animation: none!important;
    opacity: 1!important;
    filter: none!important;
    transform: none!important;
  }
  html.js .rv {
    opacity: 1;
    transform: none;
    transition: none;
  }
  html {
    scroll-behavior: auto;
  }
}

/* simulation task blocks */
.simulation-summary {
  margin-top: 56px;
}

.task {
  margin-top: 56px;
  padding-top: 40px;
  border-top: 1px solid var(--line);
}

.task .th {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 8px 18px;
  margin: 0 0 20px;
}

.task .th h3 {
  margin: 0;
  font-size: 24px;
}

.task .th h3 .tt {
  font-weight: 700;
  font-size: 1.1em;
  color: #b4531f;
}

.task .th .sub {
  font-size: 16px;
  color: var(--ink-3);
}

/* Equal-width columns: the text spans both the figure and its caption. */
.task .row {
  display: grid;
  grid-template-columns: minmax(0,1fr) minmax(0,1fr);
  grid-template-rows: 1fr auto;
  gap: 10px 40px;
  margin-top: 28px;
  align-items: stretch;
}

.task .row .fig {
  display: contents;
}

.task .row .fig .anim,.task .row .fig .box {
  grid-column: 1;
  grid-row: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 0;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 12px 10px 10px;
}

.task .row .fig .anim svg,.task .row .fig .box img {
  display: block;
  width: 100%;
  height: auto;
  max-height: 100%;
  border: 0;
  border-radius: 0;
  background: transparent;
}

.task .row .fig .cap {
  grid-column: 1;
  grid-row: 2;
  font-size: 13.5px;
  margin: 0;
}

.task .row>div:last-child {
  grid-column: 2;
  grid-row: 1 / 3;
  align-self: stretch;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.task .row p {
  font-size: 19px;
  line-height: 1.6;
  margin: 0 0 16px;
}

.task .row p:last-child {
  margin-bottom: 0;
}

.task .row .lead {
  font-family: var(--display);
  font-weight: 700;
  font-size: 22px;
  letter-spacing: -.01em;
  color: var(--ink);
  margin-bottom: 10px;
}

#method .fig.plain {
  max-width: 820px;
}

/* animated figures */
.anim {
  position: relative;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 12px 8px 8px;
}

.anim svg {
  display: block;
  width: 100%;
  height: auto;
}

.anim.arch {
  background: #fff;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 10px;
}

.anim.arch svg {
  width: 100%;
  height: auto;
}

.anim.arch svg text {
  font-family: 'DejaVu Sans Mono',Menlo,monospace!important;
}

/* Real robot: setup, full-width executions, then curves beside key results. */
.real-setup,.real-results {
  display: grid;
  grid-template-columns: minmax(0,1.2fr) minmax(0,1fr);
  gap: 32px 40px;
  align-items: stretch;
  margin-top: 32px;
}

.real-setup .fig,.real-results .fig {
  margin: 0;
  min-width: 0;
  display: flex;
  flex-direction: column;
}

.real-setup .rope-photo {
  flex: 1;
  display: flex;
  align-items: center;
  background: #1e1e1e;
  border-radius: 8px;
  overflow: hidden;
}

.real-setup .rope-photo img {
  border: 0;
  border-radius: 0;
  background: transparent;
}

.real-setup .setup-copy {
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 24px;
}

.real-setup h4 {
  margin: 0 0 8px;
  font-family: var(--display);
  font-size: 18px;
  line-height: 1.3;
}

.real-setup p {
  margin: 0;
  font-size: 17px;
  line-height: 1.6;
}

.real-frames {
  margin-top: 40px;
}

.real-frames img {
  border-radius: 10px;
}

.real-results {
  margin-top: 40px;
  padding-top: 36px;
  border-top: 1px solid var(--line);
}

.real-results .anim {
  flex: 1;
  display: flex;
  align-items: center;
  min-height: 0;
}

.real-results .anim svg {
  width: 100%;
  height: auto;
}

.real-results .stats {
  grid-template-columns: 1fr;
  align-content: space-between;
  gap: 24px;
  margin: 0;
}

.real-results .stats>div+div {
  border-top: 1px solid var(--line);
  padding-top: 20px;
}

.real-results .stats h4 {
  margin: 0 0 10px;
  font-size: 17px;
  font-weight: 700;
  color: #b4531f;
}

.real-results .stats .n {
  font-size: clamp(30px,3vw,40px);
}

.real-setup .cap,.real-results .cap {
  font-size: 14px;
  line-height: 1.55;
}

/* Responsive layouts (desktop defaults above). */
@media (max-width: 960px) {
  .secnav {
    display: none;
  }
  .grid3 {
    grid-template-columns: 1fr;
  }
  .stats {
    grid-template-columns: 1fr;
    gap: 20px;
  }
  .task .row {
    grid-template-columns: 1fr;
    grid-template-rows: auto auto auto;
  }
  .task .row>div:last-child {
    grid-column: 1;
    grid-row: 3;
    display: block;
    margin-top: 8px;
  }
  section.s,.band>.s {
    grid-template-columns: 1fr;
    gap: 20px 0;
  }
  .rail {
    position: static;
  }
  .lbl {
    font-size: 24px;
  }
  .real-setup,.real-results {
    grid-template-columns: 1fr;
  }
  .real-setup .rope-photo {
    flex: none;
  }
  .real-results .stats {
    grid-template-columns: repeat(3,minmax(0,1fr));
    gap: 24px;
  }
  .real-results .stats>div+div {
    border-top: 0;
    padding-top: 0;
  }
  .real-results .anim {
    flex: none;
  }
  .real-results .fig {
    max-width: 680px;
    margin: 0 auto;
  }
}

@media (max-width: 720px) {
  .hero.closed .cta {
    visibility: hidden;
  }
  .slotR {
    display: none;
  }
  .ctain {
    flex-wrap: wrap;
  }
  .ctabox {
    height: auto;
  }
  .hint {
    display: none;
  }
  .stack {
    bottom: 32px;
    gap: 16px;
  }
  .band {
    padding: 64px var(--gut) 72px;
  }
}

@media (max-width: 600px) {
  .real-results .stats {
    grid-template-columns: 1fr;
  }
  .real-results .stats>div+div {
    border-top: 1px solid var(--line);
    padding-top: 20px;
  }
  .real-setup,.real-results {
    gap: 24px;
  }
  .real-results .stats .n {
    font-size: 36px;
  }
}