@font-face {
  font-family: "Pretendard";
  src: url("./assets/fonts/Pretendard-Regular.woff2") format("woff2");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Pretendard";
  src: url("./assets/fonts/Pretendard-SemiBold.woff2") format("woff2");
  font-weight: 600;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Pretendard";
  src: url("./assets/fonts/Pretendard-Bold.woff2") format("woff2");
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

:root {
  --canvas: #ffffff;
  --canvas-parchment: #f5f5f7;
  --surface-pearl: #fafafc;
  --surface-dark: #272729;
  --surface-dark-2: #2a2a2c;
  --surface-black: #000000;
  --ink: #1d1d1f;
  --body-muted: #6e6e73;
  --body-on-dark: #ffffff;
  --body-muted-dark: #cccccc;
  --primary: #0066cc;
  --primary-focus: #0071e3;
  --primary-on-dark: #2997ff;
  --hairline: #e0e0e0;
  --hairline-soft: rgba(0, 0, 0, 0.08);
  --image-shadow: rgba(0, 0, 0, 0.22) 3px 5px 30px 0;
  --tile-space: 80px;
  --radius-sm: 8px;
  --radius-card: 8px;
  --radius-pill: 9999px;
  --transition: 0.2s ease;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  color: var(--ink);
  background: var(--canvas);
  font-family: "Pretendard", system-ui, -apple-system, BlinkMacSystemFont, "Apple SD Gothic Neo", "Malgun Gothic", sans-serif;
  font-size: 17px;
  line-height: 1.47;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1,
h2,
h3,
h4,
p {
  margin: 0;
  letter-spacing: 0;
}

h1,
h2,
h3,
h4 {
  font-weight: 600;
  line-height: 1.1;
}

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

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

.site-bg {
  display: none;
}

.container {
  width: min(980px, calc(100% - 48px));
  margin: 0 auto;
}

.section {
  padding: var(--tile-space) 0;
  background: var(--canvas);
}

section[id] {
  scroll-margin-top: 64px;
}

.section-head {
  margin-bottom: 32px;
  text-align: center;
}

.section-head h2 {
  font-size: 40px;
}

.eyebrow {
  margin-bottom: 10px;
  color: var(--body-muted);
  font-size: 14px;
  font-weight: 600;
  line-height: 1.3;
  text-transform: uppercase;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  background: var(--surface-black);
  color: var(--body-on-dark);
}

.topbar .topbar-inner {
  min-height: 44px;
  width: min(1440px, calc(100% - 40px));
  display: flex;
  align-items: center;
  gap: 18px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
  flex: 1 1 auto;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--canvas);
  color: var(--surface-black);
  font-size: 11px;
  font-weight: 700;
  flex-shrink: 0;
}

.brand-text {
  min-width: 0;
  overflow: hidden;
  color: rgba(255, 255, 255, 0.9);
  font-size: 12px;
  font-weight: 400;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  flex-shrink: 0;
}

.lang-btn,
.nav-toggle {
  min-height: 30px;
  border: 0;
  border-radius: var(--radius-sm);
  background: rgba(255, 255, 255, 0.12);
  color: rgba(255, 255, 255, 0.86);
  cursor: pointer;
  transition: transform var(--transition), background var(--transition), color var(--transition);
}

.lang-btn {
  padding: 0 10px;
  font: inherit;
  font-size: 12px;
}

.lang-btn.is-active {
  background: var(--primary);
  color: var(--body-on-dark);
}

.lang-btn:active,
.nav-toggle:active,
.btn:active,
.pub-links a:active {
  transform: scale(0.95);
}

.nav {
  display: flex;
  align-items: center;
  gap: 18px;
  margin-left: auto;
}

.nav a {
  color: rgba(255, 255, 255, 0.72);
  font-size: 12px;
  font-weight: 400;
  white-space: nowrap;
  transition: color var(--transition);
}

.nav a:hover,
.nav a:focus-visible,
.nav a.is-active {
  color: var(--body-on-dark);
}

.nav-toggle {
  display: none;
  width: 34px;
  padding: 0;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 4px;
}

.nav-toggle span {
  display: block;
  width: 16px;
  height: 1px;
  background: currentColor;
}

.hero {
  display: flex;
  align-items: center;
  padding: 76px 0 80px;
  background: var(--canvas);
}

.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 760px);
  justify-content: center;
  align-items: center;
  text-align: center;
}

.hero-copy {
  max-width: 760px;
  margin: 0 auto;
}

.hero-copy h1 {
  margin-bottom: 14px;
  font-size: 48px;
  word-break: keep-all;
}

.hero-copy > p:not(.eyebrow) {
  max-width: 640px;
  margin: 0 auto;
  color: var(--body-muted);
  font-size: 21px;
  font-weight: 400;
  line-height: 1.47;
  word-break: keep-all;
}

#professor,
#activities {
  background: var(--canvas-parchment);
}

#research {
  background: var(--surface-dark);
  color: var(--body-on-dark);
}

#research {
  padding-bottom: 0;
}

#research .eyebrow,
#research .section-head h2 {
  color: var(--body-on-dark);
}

#research .section-head .eyebrow {
  color: var(--body-muted-dark);
}

.professor-card {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 40px;
  align-items: center;
}

.photo-block {
  max-width: 240px;
}

.profile-photo {
  width: 100%;
  aspect-ratio: 4 / 5;
  object-fit: cover;
  border-radius: var(--radius-card);
  box-shadow: var(--image-shadow);
}

.professor-info h3 {
  margin-bottom: 18px;
  font-size: 34px;
}

.professor-info h3 a,
.link-row a,
.pub-links a,
.publication-actions a,
.nav a.is-active {
  color: var(--primary);
}

.professor-info > p {
  margin-bottom: 28px;
  color: var(--body-muted);
  font-size: 21px;
  line-height: 1.47;
}

.metric-strip {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0;
  margin-bottom: 28px;
  border-top: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
}

.metric-strip div {
  padding: 17px 16px 17px 0;
  border-right: 1px solid var(--hairline);
}

.metric-strip div:last-child {
  border-right: 0;
}

.metric-strip strong,
.metric-strip span {
  display: block;
}

.metric-strip strong {
  margin-bottom: 4px;
  font-size: 28px;
  font-weight: 600;
}

.metric-strip span {
  color: var(--body-muted);
  font-size: 13px;
  line-height: 1.35;
}

.profile-list {
  display: grid;
  gap: 0;
  margin: 0;
  padding: 0;
  list-style: none;
  border-top: 1px solid var(--hairline);
}

.profile-list li {
  display: grid;
  grid-template-columns: 110px 1fr;
  gap: 18px;
  padding: 17px 0;
  border-bottom: 1px solid var(--hairline);
}

.profile-list span {
  color: var(--ink);
  font-size: 14px;
  font-weight: 600;
}

.profile-list p {
  color: var(--body-muted);
  font-size: 17px;
}

.link-row {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin-top: 24px;
}

.link-row a {
  font-size: 17px;
}

.link-row a::after,
.pub-links a::after,
.publication-actions a::after {
  content: " >";
}

.members-grid {
  display: grid;
  grid-template-columns: 1fr;
}

.member-group {
  text-align: center;
}

.member-group h3 {
  margin-bottom: 32px;
  font-size: 28px;
}

.member-group ul {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 48px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.member-item {
  width: 220px;
  display: grid;
  justify-items: center;
  gap: 14px;
}

.member-photo {
  width: 148px;
  height: 148px;
  object-fit: cover;
  border-radius: 50%;
  box-shadow: var(--image-shadow);
}

.member-detail {
  display: grid;
  gap: 4px;
}

.member-detail strong {
  font-size: 17px;
  font-weight: 600;
}

.member-detail span {
  color: var(--body-muted);
  font-size: 14px;
  line-height: 1.43;
}

.research-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
  margin-bottom: 0;
}

.research-card {
  border: 1px solid rgba(255, 255, 255, 0.12);
  border-radius: var(--radius-card);
  background: var(--surface-dark-2);
}

.research-card {
  min-height: 260px;
  padding: 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.research-card:last-child:nth-child(odd) {
  grid-column: 1 / -1;
  min-height: 0;
}

.research-card h3 {
  font-size: 24px;
  line-height: 1.22;
}

.research-subtitle {
  display: block;
  margin-top: 8px;
  color: var(--body-muted-dark);
  font-size: 14px;
  font-weight: 400;
}

.research-card p,
.research-points {
  color: var(--body-muted-dark);
  font-size: 17px;
}

.research-points {
  display: grid;
  gap: 10px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.research-points li {
  padding-top: 12px;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
}

.research-figures {
  margin: 56px 0 0;
  padding: 64px 0;
  background: var(--canvas);
  color: var(--ink);
  box-shadow: 0 0 0 100vmax var(--canvas);
  clip-path: inset(0 -100vmax);
}

.research-figures .eyebrow {
  color: var(--body-muted);
}

.research-figures-head {
  margin-bottom: 28px;
  text-align: center;
}

.research-figures-head h3 {
  font-size: 34px;
}

.research-figure-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
}

.research-figure {
  margin: 0;
  border: 1px solid var(--hairline);
  border-radius: var(--radius-card);
  overflow: hidden;
  background: var(--canvas);
}

.research-figure-media {
  min-height: 360px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  border-bottom: 1px solid var(--hairline);
}

.research-figure-media.is-light {
  background: var(--surface-pearl);
}

.research-figure-media.is-muted {
  background: var(--canvas-parchment);
}

.research-figure-media.is-dark {
  background: var(--surface-black);
}

.research-figure-media img {
  width: 100%;
  height: auto;
  max-height: 520px;
  object-fit: contain;
}

.research-figure figcaption {
  display: grid;
  gap: 8px;
  padding: 17px 20px 20px;
}

.research-figure figcaption strong {
  font-size: 17px;
  font-weight: 600;
}

.research-figure figcaption span {
  color: var(--body-muted);
  font-size: 14px;
  line-height: 1.43;
}

.project-board {
  padding: 64px 0;
  border: 0;
  border-radius: 0;
  background: var(--canvas-parchment);
  color: var(--ink);
  box-shadow: 0 0 0 100vmax var(--canvas-parchment);
  clip-path: inset(0 -100vmax);
}

.project-board h3 {
  margin-bottom: 22px;
  font-size: 34px;
  text-align: center;
}

.project-item {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 17px 0;
  border-top: 1px solid var(--hairline);
}

.project-item:first-of-type {
  border-top: 0;
}

.project-item h4 {
  margin-bottom: 6px;
  font-size: 17px;
  font-weight: 600;
}

.project-item p {
  color: var(--body-muted);
}

.tag {
  min-width: max-content;
  height: 30px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0 12px;
  border-radius: var(--radius-pill);
  background: var(--primary);
  color: var(--body-on-dark);
  font-size: 14px;
}

.publication-wrap {
  display: grid;
  gap: 0;
  border-top: 1px solid var(--hairline);
}

.pub-item {
  padding: 24px 0;
  border-bottom: 1px solid var(--hairline);
}

.pub-meta {
  margin-bottom: 8px;
  color: var(--body-muted);
  font-size: 14px;
}

.pub-meta strong {
  color: var(--ink);
  font-weight: 600;
}

.pub-item h3 {
  max-width: 880px;
  margin-bottom: 8px;
  font-size: 21px;
  line-height: 1.32;
}

.pub-authors {
  margin-bottom: 12px;
  color: var(--body-muted);
  font-size: 14px;
}

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

.pub-links a {
  font-size: 17px;
}

.publication-actions {
  display: flex;
  justify-content: center;
  margin-top: 28px;
}

.publication-actions a {
  font-size: 17px;
}

.activities-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
}

.recruiting-panel {
  max-width: 760px;
  margin: 0 auto;
}

.timeline,
.activity-gallery {
  display: grid;
  gap: 0;
}

.timeline article,
.activity-gallery article {
  padding: 20px 0;
  border-bottom: 1px solid var(--hairline);
}

.timeline article:first-child,
.activity-gallery article:first-child {
  border-top: 1px solid var(--hairline);
}

.timeline .date {
  margin-bottom: 4px;
  color: var(--body-muted);
  font-size: 14px;
}

.timeline h3,
.activity-gallery h3 {
  margin-bottom: 6px;
  font-size: 21px;
}

.timeline p,
.activity-gallery p {
  color: var(--body-muted);
}

.activity-gallery a {
  color: var(--primary);
}

.activity-gallery {
  grid-template-columns: 1fr;
}

.lang-btn:focus-visible,
.nav-toggle:focus-visible,
.btn:focus-visible {
  outline: 2px solid var(--primary-focus);
  outline-offset: 2px;
}

.btn {
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--primary);
  border-radius: var(--radius-pill);
  padding: 0 22px;
  background: var(--primary);
  color: var(--body-on-dark);
  font: inherit;
  font-size: 17px;
  cursor: pointer;
  transition: transform var(--transition), background var(--transition);
}

.btn:hover {
  background: var(--primary-focus);
}

.footer {
  padding: 64px 0;
  background: var(--canvas-parchment);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr auto;
  gap: 32px;
}

.footer h3 {
  margin-bottom: 8px;
  font-size: 14px;
  font-weight: 600;
}

.footer p {
  color: var(--body-muted);
  font-size: 12px;
  line-height: 1.6;
}

[data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

[data-reveal].is-visible {
  opacity: 1;
  transform: none;
}

@media (max-width: 1160px) {
  .nav-toggle {
    display: inline-flex;
  }

  .nav {
    position: absolute;
    top: 44px;
    right: 0;
    left: 0;
    display: none;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    margin: 0;
    padding: 10px 24px 18px;
    background: var(--surface-black);
  }

  .nav a {
    width: 100%;
    padding: 12px 0;
    border-top: 1px solid rgba(255, 255, 255, 0.12);
    font-size: 17px;
  }

  .nav.open {
    display: flex;
  }
}

@media (max-width: 1080px) {
  .research-grid,
  .research-figure-grid,
  .activities-grid,
  .footer-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 920px) {
  .hero-grid {
    grid-template-columns: 1fr;
    gap: 32px;
    text-align: center;
  }

  .hero-copy,
  .hero-copy > p:not(.eyebrow) {
    margin: 0 auto;
  }

  .professor-card {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .photo-block {
    max-width: 220px;
    margin: 0 auto;
  }
}

@media (max-width: 640px) {
  :root {
    --tile-space: 56px;
  }

  .container {
    width: min(100% - 32px, 980px);
  }

  .topbar .topbar-inner {
    width: calc(100% - 24px);
    gap: 8px;
  }

  .brand-text {
    max-width: 146px;
  }

  .lang-btn {
    min-height: 28px;
    padding: 0 8px;
  }

  .hero {
    min-height: 0;
    padding: 52px 0 56px;
  }

  .hero-grid {
    gap: 28px;
  }

  .hero-copy h1 {
    font-size: 34px;
  }

  .hero-copy > p:not(.eyebrow) {
    font-size: 19px;
  }

  .section-head h2 {
    font-size: 34px;
  }

  .professor-info h3 {
    font-size: 28px;
  }

  .professor-info > p {
    font-size: 19px;
  }

  .metric-strip {
    grid-template-columns: 1fr;
  }

  .metric-strip div {
    padding-right: 0;
    border-right: 0;
    border-bottom: 1px solid var(--hairline);
  }

  .metric-strip div:last-child {
    border-bottom: 0;
  }

  .profile-list li,
  .project-item {
    grid-template-columns: 1fr;
    flex-direction: column;
    gap: 6px;
  }

  .research-figure-media {
    min-height: 0;
    padding: 12px;
  }

  .member-group ul {
    gap: 32px;
  }

  .footer-grid {
    gap: 18px;
  }
}

@media (max-width: 419px) {
  .brand-text {
    display: none;
  }

  .hero-copy h1 {
    font-size: 28px;
  }

  .hero-copy > p:not(.eyebrow) {
    font-size: 17px;
  }

  .section-head h2 {
    font-size: 28px;
  }

  .member-item {
    width: 100%;
  }
}

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

  [data-reveal] {
    opacity: 1;
    transform: none;
    transition: none;
  }
}