:root {
  --background: #f7f8f5;
  --surface: #ffffff;
  --surface-soft: #eef3ef;
  --text: #171a1d;
  --muted-text: #5f6872;
  --line: rgba(27, 35, 42, 0.12);
  --accent: #0043ce;
  --accent-strong: #0043ce;
  --accent-warm: #c46a3a;
  --shadow-soft: 0 14px 40px rgba(20, 29, 38, 0.08);
  --shadow-media: 0 22px 62px rgba(20, 29, 38, 0.14);
  --radius: 14px;
  --radius-card: 8px;
  --radius-pill: 999px;
  --max-width: 1160px;
  --text-width: 820px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--text);
  background: linear-gradient(180deg, #fbfcfa 0, var(--background) 520px, #ffffff 100%);
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.65;
}

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

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

button {
  font: inherit;
}

/* Hero */
.hero {
  padding: 28px 20px 70px;
}

.nav {
  width: min(var(--max-width), 100%);
  margin: 0 auto 56px;
  display: flex;
  justify-content: center;
  gap: 10px;
  flex-wrap: wrap;
}

.nav a {
  padding: 8px 12px;
  color: var(--muted-text);
  font-size: 0.95rem;
  font-weight: 700;
  border-radius: var(--radius-pill);
}

.nav a:hover {
  color: var(--accent-strong);
  background: rgba(23, 109, 122, 0.08);
}

.hero-content {
  width: min(1080px, 100%);
  margin: 0 auto;
  text-align: center;
}

.venue {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin: 0 0 18px;
  padding: 6px 14px;
  color: #0043ce;
  background: rgba(0, 67, 206, 0.1);
  border: 1px solid rgba(0, 67, 206, 0.16);
  border-radius: var(--radius-pill);
  font-size: 0.9rem;
  font-weight: 800;
  letter-spacing: 0;
}

h1 {
  margin: 0 auto 18px;
  max-width: 1050px;
  font-size: 4rem;
  line-height: 1.05;
  font-weight: 850;
  letter-spacing: 0;
}

h1 span {
  display: block;
}

.subtitle {
  max-width: 820px;
  margin: 0 auto 26px;
  color: var(--muted-text);
  font-size: 1.18rem;
  line-height: 1.55;
}

.authors {
  max-width: 960px;
  margin: 24px auto 10px;
  font-size: 1.04rem;
  line-height: 1.8;
}

.authors a {
  font-weight: 650;
}

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

.affiliations {
  max-width: 980px;
  margin: 0 auto;
  color: var(--muted-text);
  font-size: 0.93rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 4px 14px;
}

.buttons {
  margin-top: 30px;
  display: flex;
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}

.button {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  gap: 10px;
  padding: 11px 18px;
  color: #ffffff;
  border-radius: var(--radius-pill);
  box-shadow: 0 10px 24px rgba(20, 29, 38, 0.13);
  font-size: 1rem;
  font-weight: 750;
  line-height: 1;
  transition: transform 160ms ease, box-shadow 160ms ease, filter 160ms ease;
}

.button:hover {
  transform: translateY(-1px);
  box-shadow: 0 14px 28px rgba(20, 29, 38, 0.18);
  filter: brightness(1.03);
}

.button i {
  font-size: 1.08em;
  line-height: 1;
}

.button .ai {
  font-size: 1.22em;
}

.button.paper {
  background: #0043ce;
}

.button.arxiv {
  background: #a2191f;
}

.button.code {
  background: #24292f;
}

.button.video-button {
  background: #005d5d;
}

.button.soon {
  cursor: default;
}

.button.soon::after {
  content: attr(data-tooltip);
  position: absolute;
  left: 50%;
  bottom: calc(100% + 8px);
  transform: translateX(-50%) translateY(4px);
  padding: 6px 9px;
  color: #ffffff;
  background: rgba(20, 24, 28, 0.92);
  border-radius: 7px;
  font-size: 0.82rem;
  font-weight: 700;
  line-height: 1;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity 140ms ease, transform 140ms ease;
}

.button.soon:hover::after,
.button.soon:focus-visible::after {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

/* Sections */
main {
  width: min(var(--max-width), calc(100% - 32px));
  margin: 0 auto 80px;
}

.section {
  padding: 62px 0;
  border-top: 1px solid var(--line);
}

.section-heading {
  margin-bottom: 28px;
  text-align: center;
}

.section-heading h2 {
  margin: 0;
  font-size: 2.25rem;
  line-height: 1.15;
  font-weight: 820;
  letter-spacing: 0;

  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
}

.section-heading h2::before,
.section-heading h2::after {
  content: "";
  width: 78px;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(23, 109, 122, 0.38));
}

.section-heading h2::after {
  background: linear-gradient(90deg, rgba(23, 109, 122, 0.38), transparent);
}

.text-section {
  width: min(var(--text-width), 100%);
  margin-left: auto;
  margin-right: auto;
}

/* Method */
.method-section {
  padding-top: 42px;
}

.method-figure {
  margin: 0;
  padding: 16px;
  background: var(--surface);
  border-radius: var(--radius);
  box-shadow: var(--shadow-media);
}

.method-figure img {
  width: 100%;
}

.method-figure figcaption,
.video-caption {
  max-width: 820px;
  margin: 14px auto 0;
  color: var(--muted-text);
  font-size: 0.96rem;
  text-align: center;
}

/* Abstract */
.abstract-text {
  color: #293039;
  font-size: 1.04rem;
}

.abstract-text p {
  margin: 0 0 1.12rem;
}

.abstract-text p:last-child {
  margin-bottom: 0;
}

/* Video */
.video-section {
  width: 100%;
}

.robot-demo-card {
  overflow: hidden;
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid rgba(27, 35, 42, 0.08);
  border-radius: var(--radius);
  box-shadow: var(--shadow-soft);
}

.panel-label {
  margin: 0;
  color: #18212b;
  font-weight: 850;
  line-height: 1.2;
}

.featured-video {
  margin-bottom: 44px;
}

.video-wrapper {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: #111417;
  border-radius: var(--radius);
  box-shadow: var(--shadow-media);
}

.video-wrapper iframe,
.video-wrapper video {
  width: 100%;
  height: 100%;
  border: 0;
  object-fit: cover;
}

.video-subsection {
  margin-top: 30px;
}

.subsection-title {
  margin: 0 0 18px;
  font-size: 1.35rem;
  line-height: 1.25;
  font-weight: 800;
  letter-spacing: 0;
}

.realworld-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
}

.realworld-item {
  min-width: 0;
}

.robot-demo-card {
  width: 100%;
  margin: 0 auto;
  padding: 14px;
}

.robot-demo-card h4 {
  margin: 0 0 14px 10px;
  color: #111a23;
  font-size: 1.3rem;
  line-height: 1.2;
  font-weight: 850;
  letter-spacing: 0;
}

.robot-demo-main {
  min-width: 0;
}

.split-demo-layout {
  display: grid;
  grid-template-columns: minmax(420px, 1.008fr) minmax(500px, 0.992fr);
  gap: 20px;
  align-items: start;
}

.realworld-panel {
  position: relative;
  overflow: hidden;
  border: 1px solid rgba(27, 35, 42, 0.08);
  border-radius: 9px;
}

.panel-label {
  position: relative;
  z-index: 1;
  font-size: 1.03rem;
}

.realworld-panel {
  display: flex;
  aspect-ratio: 16 / 9;
  min-height: 360px;
  padding: 18px;
}

.split-demo-layout .realworld-panel {
  aspect-ratio: 16 / 9;
  min-height: 0;
}

.t1-demo-card .realworld-panel {
  min-height: 0;
  aspect-ratio: 16 / 9;
}

.t1-stacked-layout {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.t1-stacked-layout .sim-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.g1-demo-card .realworld-panel {
  aspect-ratio: 16 / 6;
  min-height: 260px;
}

.realworld-panel .panel-label {
  position: absolute;
  left: 18px;
  top: 18px;
  color: #ffffff;
  text-shadow: 0 1px 16px rgba(0, 0, 0, 0.5);
}

.realworld-panel > video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 0;
}

.realworld-panel .coming-soon {
  position: relative;
  z-index: 1;
}

.placeholder-wrapper {
  display: flex;
  align-items: stretch;
  justify-content: stretch;
}

.robot-placeholder {
  background:
    radial-gradient(circle at 58% 48%, rgba(196, 106, 58, 0.36), transparent 0 9%, rgba(196, 106, 58, 0) 10%),
    radial-gradient(circle at 36% 62%, rgba(23, 109, 122, 0.42), transparent 0 8%, rgba(23, 109, 122, 0) 9%),
    linear-gradient(135deg, rgba(14, 20, 25, 0.16), rgba(14, 20, 25, 0.72)),
    linear-gradient(135deg, #dfe4df 0, #8f9c98 48%, #263136 100%);
}

.t1-placeholder {
  background:
    radial-gradient(circle at 46% 54%, rgba(196, 106, 58, 0.38), transparent 0 9%, rgba(196, 106, 58, 0) 10%),
    radial-gradient(circle at 62% 66%, rgba(23, 109, 122, 0.42), transparent 0 8%, rgba(23, 109, 122, 0) 9%),
    linear-gradient(135deg, rgba(12, 18, 20, 0.18), rgba(12, 18, 20, 0.78)),
    linear-gradient(135deg, #d9e5e2 0, #6e918c 52%, #1f363a 100%);
}

.stairs-placeholder {
  background:
    linear-gradient(135deg, rgba(12, 18, 20, 0.1), rgba(12, 18, 20, 0.72)),
    repeating-linear-gradient(135deg, #eef2ef 0 22px, #cbd5cf 22px 44px, #94a39d 44px 66px);
}

.coming-soon {
  width: min(440px, 100%);
  margin: auto;
  display: grid;
  justify-items: center;
  gap: 8px;
  color: #ffffff;
  text-align: center;
}

.coming-soon i {
  color: rgba(255, 255, 255, 0.76);
  font-size: 2.2rem;
}

.coming-soon strong {
  font-size: clamp(1.55rem, 3vw, 2.2rem);
  line-height: 1.08;
}

.coming-soon span {
  display: block;
  width: min(340px, 100%);
  max-width: 340px;
  padding: 5px 12px;
  color: rgba(255, 255, 255, 0.86);
  background: rgba(255, 255, 255, 0.14);
  border-radius: var(--radius-pill);
  font-size: 0.9rem;
  font-weight: 750;
  line-height: 1.35;
  overflow-wrap: anywhere;
}

.embedded-sim-section {
  min-width: 0;
  display: flex;
  flex-direction: column;
  position: relative;
}

.sim-section-title {
  position: absolute;
  top: -34px;
  left: 0;
  right: 0;
  margin: 0;
  display: flex;
  align-items: center;
  gap: 14px;
  color: #17202a;
  font-size: 1rem;
  line-height: 1.2;
  font-weight: 850;
  letter-spacing: 0;
  text-align: center;
}

.sim-section-title::before,
.sim-section-title::after {
  content: "";
  flex: 1;
  height: 1px;
  background: rgba(27, 35, 42, 0.11);
}

.t1-sim-title {
  position: static;
  top: auto;
  left: auto;
  right: auto;
  margin: 0;
}

.sim-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.split-demo-layout .embedded-sim-section {
  min-width: 0;
}

.sim-card {
  min-width: 0;
  overflow: hidden;
  background: var(--surface);
  border: 1px solid rgba(27, 35, 42, 0.08);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-soft);
}

.sim-video-wrapper {
  aspect-ratio: 16 / 9;
  border-radius: 0;
  box-shadow: none;
}

.sim-video-wrapper video {
  object-fit: contain;
  background: #111417;
}

.demo-label {
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  padding: 70px 18px 16px;
  color: #ffffff;
  background: linear-gradient(to top, rgba(0, 0, 0, 0.78), rgba(0, 0, 0, 0.3), rgba(0, 0, 0, 0));
  pointer-events: none;
  transition: opacity 160ms ease;
}

.sim-video-wrapper:hover .demo-label,
.sim-video-wrapper:focus-within .demo-label {
  opacity: 0;
}

.demo-label span {
  display: block;
  color: #ffffff;
  font-size: 1.12rem;
  font-weight: 850;
  line-height: 1.2;
}

.demo-label p {
  margin: 4px 0 0;
  color: rgba(255, 255, 255, 0.84);
  font-size: 0.95rem;
  line-height: 1.35;
}

.demo-label-small {
  padding: 50px 13px 13px;
}

.demo-label-small span {
  font-size: 1rem;
}

/* Citation */
.citation-section {
  padding-bottom: 36px;
}

.citation-header {
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.citation-header p {
  margin: 0;
  color: var(--muted-text);
  font-size: 0.95rem;
  font-weight: 750;
}

pre {
  margin: 0;
  overflow-x: auto;
  padding: 18px;
  color: #eef3ef;
  background: #111417;
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-soft);
  font-size: 0.94rem;
  line-height: 1.55;
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, "Liberation Mono", monospace;
}

.copy-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 38px;
  padding: 8px 13px;
  color: #ffffff;
  background: var(--accent-strong);
  border: 0;
  border-radius: var(--radius-pill);
  font-size: 0.9rem;
  font-weight: 800;
  line-height: 1;
  cursor: pointer;
  transition: transform 160ms ease, filter 160ms ease;
}

.copy-button:hover {
  transform: translateY(-1px);
  filter: brightness(1.05);
}

/* Responsive */
@media (max-width: 1080px) {
  .split-demo-layout {
    grid-template-columns: 1fr;
  }

  .sim-section-title {
    position: static;
    margin: 0 0 12px;
  }

  .sim-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 980px) {
  h1 {
    font-size: 3.2rem;
  }
}

@media (max-width: 720px) {
  .hero {
    padding: 22px 16px 52px;
  }

  .nav {
    margin-bottom: 38px;
  }

  h1 {
    font-size: 2.34rem;
  }

  .subtitle {
    font-size: 1.02rem;
  }

  .authors {
    font-size: 0.98rem;
  }

  .affiliations {
    font-size: 0.88rem;
  }

  main {
    width: min(var(--max-width), calc(100% - 24px));
    margin-bottom: 56px;
  }

  .section {
    padding: 48px 0;
  }

  .section-heading h2 {
    font-size: 1.8rem;
  }

  .video-section .section-heading h2 {
    gap: 12px;
  }

  .video-section .section-heading h2::before,
  .video-section .section-heading h2::after {
    width: 42px;
  }

  .sim-grid,
  .t1-stacked-layout .sim-grid {
    grid-template-columns: 1fr;
  }

  .realworld-panel,
  .t1-demo-card .realworld-panel {
    min-height: 250px;
  }

  .g1-demo-card .realworld-panel {
    aspect-ratio: 16 / 9;
    min-height: 0;
  }

  .citation-header {
    align-items: flex-start;
    flex-direction: column;
  }

  pre {
    font-size: 0.84rem;
  }
}

@media (max-width: 420px) {
  .button {
    width: calc(50% - 5px);
    padding-left: 10px;
    padding-right: 10px;
  }

  .video-section .section-heading h2::before,
  .video-section .section-heading h2::after {
    width: 24px;
  }

  .sim-section-title {
    gap: 10px;
  }
}