:root {
  --bg: #f5f5f3;
  --bg-accent: #efefec;
  --surface: rgba(255, 255, 255, 0.9);
  --surface-strong: #ffffff;
  --surface-muted: #f7f7f5;
  --text: #161616;
  --muted: #666666;
  --line: rgba(22, 22, 22, 0.1);
  --line-strong: rgba(22, 22, 22, 0.18);
  --accent: #222222;
  --accent-link: #0f4c81;
  --accent-soft: #f0f0ed;
  --shadow: 0 22px 60px rgba(0, 0, 0, 0.05);
  --shadow-soft: 0 10px 28px rgba(0, 0, 0, 0.04);
  --radius-xl: 0px;
  --radius-lg: 0px;
  --radius-md: 0px;
  --max-width: 1120px;
  --font-sans: "Manrope", "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  font-family: var(--font-sans);
  color: var(--text);
  background: linear-gradient(180deg, var(--bg-accent) 0%, var(--bg) 24%, #fafaf8 100%);
  line-height: 1.7;
  overflow-wrap: anywhere;
}

a {
  color: inherit;
}

.page-shell {
  position: relative;
  overflow: hidden;
}

.container {
  position: relative;
  z-index: 1;
  width: min(calc(100% - 40px), var(--max-width));
  margin: 0 auto;
}

.header {
  padding: 34px 0 20px;
}

.hero-card {
  display: grid;
  grid-template-columns: minmax(220px, 280px) minmax(0, 1fr);
  gap: 38px;
  padding: 34px;
  border: 1px solid var(--line);
  border-radius: var(--radius-xl);
  background: var(--surface-strong);
  box-shadow: var(--shadow);
}

.hero-left {
  display: flex;
  flex-direction: column;
  gap: 22px;
  align-items: flex-start;
}

.photo-frame {
  position: relative;
  padding: 0;
  border: 1px solid var(--line);
  background: #ffffff;
  width: fit-content;
  max-width: 100%;
}

.profile-photo {
  display: block;
  width: 100%;
  height: auto;
  max-width: 240px;
  object-fit: contain;
}

.hero-right {
  display: flex;
  flex-direction: column;
  gap: 18px;
  justify-content: center;
}

.item-date,
.logo-date {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.item-date,
.logo-date {
  color: var(--accent);
}

.hero-right h1 {
  font-size: clamp(2.5rem, 4.4vw, 4.2rem);
  font-weight: 800;
  letter-spacing: -0.05em;
  line-height: 0.96;
}

.hero-subtitle {
  max-width: 56rem;
  color: var(--muted);
  font-size: 1.02rem;
}

.hero-summary {
  max-width: 52rem;
  font-size: 1rem;
  color: #2b2b2b;
}

.contact-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.contact-chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 42px;
  height: 42px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 0;
  background: var(--surface-muted);
  text-decoration: none;
  color: var(--muted);
  transition: transform 0.2s ease, background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}

.contact-chip i {
  font-size: 1rem;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.contact-chip:hover {
  transform: translateY(-1px);
  color: var(--text);
  border-color: var(--line-strong);
  background: var(--surface-strong);
}

.contact-chip:focus-visible,
.section-nav a:focus-visible,
.publication-title-link:focus-visible {
  outline: 2px solid rgba(15, 76, 129, 0.32);
  outline-offset: 2px;
}

.areas {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  list-style: none;
}

.hero-areas {
  margin-top: 2px;
}

.areas li {
  padding: 7px 12px;
  border-radius: 999px;
  background: #f1f1ee;
  color: #353535;
  font-size: 0.88rem;
  font-weight: 700;
}

.section-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 18px;
  padding: 8px;
  border-radius: 0;
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid var(--line);
  overflow-x: auto;
  scrollbar-width: none;
  scroll-snap-type: x proximity;
  -webkit-overflow-scrolling: touch;
}

.section-nav::-webkit-scrollbar {
  display: none;
}

.section-nav a {
  padding: 10px 14px;
  border-radius: 0;
  text-decoration: none;
  color: var(--muted);
  font-weight: 700;
  transition: background-color 0.2s ease, color 0.2s ease, transform 0.2s ease;
  scroll-snap-align: start;
  white-space: nowrap;
}

.section-nav a:hover,
.section-nav a.active {
  background: #ffffff;
  color: var(--text);
  transform: translateY(0);
}

.main {
  padding: 10px 0 80px;
}

.content-stack {
  display: grid;
  gap: 22px;
}

.section {
  padding: 30px 32px;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: rgba(255, 255, 255, 0.86);
  box-shadow: var(--shadow-soft);
  scroll-margin-top: 120px;
}

.section-heading {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  margin-bottom: 20px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--line);
}

.section h2 {
  font-size: clamp(1.6rem, 2.8vw, 2.2rem);
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1;
}

.card-list,
.publication-list {
  list-style: none;
}

.compact-rows {
  list-style: none;
  display: grid;
  gap: 0;
}

.news-panel {
  max-height: clamp(160px, 28vh, 220px);
  overflow-y: auto;
  padding-right: 4px;
  overscroll-behavior: contain;
}

.news-panel::-webkit-scrollbar {
  width: 10px;
}

.news-panel::-webkit-scrollbar-thumb {
  background: rgba(22, 22, 22, 0.18);
  border: 2px solid #ffffff;
}

.news-panel::-webkit-scrollbar-track {
  background: transparent;
}

.compact-rows li {
  display: grid;
  grid-template-columns: 92px minmax(0, 1fr);
  gap: 10px;
  padding: 7px 0;
  border-bottom: 1px solid var(--line);
}

.news-list .item-date {
  font-size: 0.68rem;
  white-space: nowrap;
}

.news-list p {
  font-size: 0.95rem;
  line-height: 1.45;
}

.compact-rows li:last-child {
  border-bottom: 0;
}

.card-list {
  display: grid;
  gap: 12px;
}

.card-list li {
  display: grid;
  grid-template-columns: 120px minmax(0, 1fr);
  gap: 18px;
  padding: 18px 20px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: #ffffff;
}

.card-list li p,
.publication-list li p,
.career-logo-item p {
  margin: 0;
}

.muted {
  color: var(--muted);
}

.publication-groups {
  display: grid;
  gap: 28px;
}

.publication-group {
  display: grid;
  grid-template-columns: 88px minmax(0, 1fr);
  gap: 18px;
  align-items: start;
}

.publication-year-rail {
  position: sticky;
  top: 120px;
}

.publication-year-heading {
  display: inline-block;
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
}

.publication-list {
  display: grid;
  gap: 12px;
}

.publication-card {
  display: block;
  padding: 15px 18px;
  border: 1px solid var(--line);
  background: #ffffff;
  transition: border-color 0.2s ease, box-shadow 0.2s ease, transform 0.2s ease;
}

.publication-card:hover {
  border-color: rgba(15, 76, 129, 0.2);
  box-shadow: 0 8px 24px rgba(15, 76, 129, 0.06);
  transform: translateY(-1px);
}

.publication-list h4 {
  font-size: 1.02rem;
  line-height: 1.4;
  margin-bottom: 6px;
  text-wrap: balance;
}

.publication-title-link {
  text-decoration: none;
  background-image: linear-gradient(currentColor, currentColor);
  background-position: 0 100%;
  background-repeat: no-repeat;
  background-size: 0% 1px;
  transition: color 0.2s ease, background-size 0.24s ease;
}

.publication-title-link:hover {
  color: var(--accent-link);
  background-size: 100% 1px;
}

.publication-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px 12px;
}

.publication-meta p {
  margin: 0;
}

.publication-authors {
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.45;
}

.publication-venue {
  font-weight: 700;
  font-size: 0.88rem;
  color: var(--text);
  padding-left: 12px;
  border-left: 1px solid var(--line);
}

.publication-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  list-style: none;
  margin-top: 9px;
}

.publication-tags li {
  padding: 4px 8px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface-muted);
  font-size: 0.72rem;
  font-weight: 700;
  color: #494949;
}

.detail-list {
  list-style: none;
  display: grid;
  gap: 0;
}

.detail-list li {
  display: grid;
  grid-template-columns: 88px minmax(0, 1fr);
  gap: 14px;
  padding: 14px 0;
  border-bottom: 1px solid rgba(22, 22, 22, 0.08);
}

.detail-list li:last-child {
  border-bottom: 0;
}

.detail-copy {
  display: grid;
  gap: 3px;
}

.detail-copy p {
  margin: 0;
}

.career-logos {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

.career-logo-item {
  display: grid;
  grid-template-columns: 76px minmax(0, 1fr);
  align-items: center;
  gap: 20px;
  min-height: 0;
  padding: 14px 0;
  border-bottom: 1px solid rgba(22, 22, 22, 0.08);
  background: transparent;
}

.career-logo-item:last-child {
  border-bottom: 0;
}

.logo-badge {
  display: grid;
  place-items: center;
  width: 76px;
  height: 76px;
  padding: 4px;
  background: transparent;
}

.logo-badge-ku {
  width: 76px;
  height: 76px;
  padding: 2px;
  overflow: hidden;
}

.org-logo-large {
  width: 100%;
  height: 100%;
  object-fit: contain;
}

.org-logo-ku {
  width: 84%;
  height: 84%;
  max-width: 84%;
  transform: none;
  object-fit: contain;
}

.career-logo-item p {
  font-weight: 700;
  line-height: 1.35;
  font-size: 1rem;
}

.career-copy {
  min-width: 0;
  display: grid;
  gap: 2px;
}

.career-copy p {
  margin: 0;
}

.career-org {
  color: var(--muted);
  font-size: 0.92rem;
  font-weight: 500;
  line-height: 1.45;
}

.career-copy .logo-date {
  margin-top: 4px;
  white-space: nowrap;
}

.project-list {
  list-style: none;
  display: grid;
  grid-template-columns: 1fr;
  gap: 0;
}

.project-list li {
  display: grid;
  grid-template-columns: 108px minmax(0, 1fr);
  gap: 16px;
  align-items: center;
  padding: 14px 0;
  border-bottom: 1px solid rgba(22, 22, 22, 0.08);
  background: transparent;
}

.project-list li:last-child {
  border-bottom: 0;
}

.project-logo-wrap {
  display: flex;
  justify-content: center;
}

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

.project-logo-samsung-research {
  width: 150%;
  max-width: none;
}

.murf-logo {
  transform: scale(1.15);
}

.project-copy {
  display: grid;
  gap: 4px;
}

.project-copy strong {
  line-height: 1.45;
  text-wrap: balance;
}

.footer {
  padding: 0 0 40px;
}

.visitor-widget {
  display: grid;
  justify-items: center;
  gap: 10px;
  margin-bottom: 16px;
}

.visitor-widget-label {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--muted);
}

.visitor-widget-embed {
  display: flex;
  justify-content: center;
  width: 100%;
  max-width: 180px;
  margin: 0 auto;
  overflow: hidden;
}

.footer p {
  text-align: center;
  color: var(--muted);
  font-size: 0.9rem;
}

.top-button {
  position: fixed;
  right: 24px;
  bottom: 24px;
  z-index: 3;
  width: 48px;
  height: 48px;
  border: 0;
  border-radius: 0;
  background: #222222;
  color: #ffffff;
  box-shadow: 0 12px 28px rgba(0, 0, 0, 0.14);
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: opacity 0.2s ease, visibility 0.2s ease, transform 0.2s ease;
}

.top-button.show {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.55s ease, transform 0.55s ease;
}

.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

@media (max-width: 920px) {
  .hero-card {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .hero-left {
    max-width: none;
    flex-direction: row;
    align-items: flex-start;
  }

  .photo-frame {
    flex: 0 0 auto;
  }

  .contact-links {
    align-content: flex-start;
  }

  .section-nav {
    border-radius: 0;
    flex-wrap: nowrap;
    padding-bottom: 10px;
  }

  .publication-group,
  .card-list li,
  .project-list,
  .project-list li,
  .detail-list li,
  .compact-rows li {
    grid-template-columns: 1fr;
  }

  .publication-year-rail {
    position: static;
  }

  .publication-group {
    gap: 12px;
  }

  .publication-venue {
    padding-left: 0;
    border-left: 0;
  }
}

@media (max-width: 640px) {
  .container {
    width: min(calc(100% - 24px), var(--max-width));
  }

  .header {
    padding-top: 18px;
  }

  .hero-card,
  .section {
    padding: 22px;
  }

  .hero-left {
    flex-direction: column;
    gap: 16px;
  }

  .photo-frame {
    width: 100%;
  }

  .hero-right h1 {
    font-size: 2.6rem;
  }

  .hero-subtitle,
  .hero-summary {
    font-size: 0.95rem;
  }

  .areas {
    gap: 6px;
  }

  .areas li,
  .publication-tags li {
    font-size: 0.74rem;
  }

  .section-heading {
    align-items: flex-start;
  }

  .section-nav a {
    flex: 0 0 auto;
  }

  .project-list li {
    gap: 12px;
    padding: 12px 0;
  }

  .career-logo-item {
    grid-template-columns: 76px minmax(0, 1fr);
    gap: 18px;
    align-items: start;
  }

  .project-logo-wrap {
    justify-content: flex-start;
  }

  .logo-badge,
  .logo-badge-ku {
    width: 68px;
    height: 68px;
  }

  .news-panel {
    max-height: min(180px, 32vh);
    padding-right: 2px;
  }

  .top-button {
    right: 16px;
    bottom: 16px;
  }
}

@media (max-width: 420px) {
  .hero-card,
  .section {
    padding: 18px;
  }

  .hero-right h1 {
    font-size: 2.15rem;
  }

  .news-list p,
  .detail-copy p,
  .project-copy p,
  .publication-authors,
  .publication-venue {
    font-size: 0.9rem;
  }

  .compact-rows li,
  .detail-list li {
    gap: 8px;
    padding: 6px 0;
  }

  .project-list li {
    padding: 10px 0;
  }

  .project-logo-wrap {
    justify-content: center;
  }

  .career-logo-item {
    grid-template-columns: 1fr;
    align-items: flex-start;
    gap: 12px;
  }

  .career-copy .logo-date {
    white-space: normal;
  }

  .publication-tags,
  .contact-links {
    gap: 6px;
  }

  .news-list .item-date,
  .detail-list .item-date {
    font-size: 0.64rem;
  }

  .visitor-widget {
    margin-bottom: 12px;
  }
}