:root {
  --text: #222;
  --muted: #666;
  --line: #e2e2e2;
  --bg: #ffffff;
  --link: #1565c0;
  --tag-bg: #f1f3f5;
  --tag-text: #495057;
  --block-bg: #fafafa;
  --block-border: #ebebeb;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans KR", Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

main {
  max-width: 900px;
  margin: 0 auto;
  padding: 2.5rem 1.75rem 5rem;
}

a {
  color: var(--link);
  text-decoration: none;
}

a:hover { text-decoration: underline; }

/* Lang switcher */
html[data-lang="ko"] .en { display: none !important; }
html[data-lang="en"] .ko { display: none !important; }

.lang-toggle {
  display: inline-flex;
  gap: 0.25rem;
  margin-left: auto;
  padding-left: 0.5rem;
}

.lang-btn {
  background: none;
  border: 1px solid var(--block-border);
  color: var(--muted);
  padding: 0.2rem 0.55rem;
  border-radius: 4px;
  cursor: pointer;
  font: inherit;
  font-size: 0.8rem;
  line-height: 1.3;
  transition: all 0.15s;
}

.lang-btn:hover { color: var(--text); border-color: #c5c5c5; }

.lang-btn.active {
  background: var(--text);
  color: #fff;
  border-color: var(--text);
}

/* Top nav */
.topnav {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  font-size: 0.95rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--line);
  margin-bottom: 1.75rem;
  color: var(--muted);
}

.nav-links a { margin-right: 0.4rem; }
.nav-links a + a { margin-left: 0.4rem; }
.nav-links .sep { color: #bbb; margin: 0 0.25rem; }

/* Header (home) */
header {
  display: grid;
  grid-template-columns: 1fr 180px;
  gap: 2rem;
  align-items: start;
  margin-bottom: 2rem;
}

h1 {
  font-size: 2rem;
  font-weight: 700;
  margin: 0 0 0.5rem;
  letter-spacing: -0.01em;
}

h1 .kr {
  color: var(--muted);
  font-weight: 500;
  font-size: 1.6rem;
  margin-left: 0.25rem;
}

.affil {
  color: var(--text);
  margin: 0 0 0.75rem;
  font-size: 1rem;
}

.socials {
  font-size: 0.92rem;
  color: var(--muted);
}

.socials a { color: var(--link); }

.photo {
  width: 180px;
  height: 220px;
  object-fit: cover;
  border: 1px solid var(--line);
  border-radius: 4px;
  display: block;
  background: #f5f5f5;
}

/* Bio */
.bio p { margin: 0 0 0.85rem; }
.bio strong { font-weight: 600; }

/* Sections — soft block cards */
section {
  margin-top: 1.5rem;
  background: var(--block-bg);
  border: 1px solid var(--block-border);
  border-radius: 8px;
  padding: 1.5rem 1.75rem;
}

h2 {
  font-size: 1.2rem;
  font-weight: 700;
  margin: 0 0 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--block-border);
  color: var(--text);
  letter-spacing: -0.005em;
}

p { margin: 0 0 0.85rem; }
p:last-child { margin-bottom: 0; }
strong { font-weight: 600; }
em { font-style: italic; }

/* Research interests */
.research-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.research-list li {
  padding: 0.65rem 0;
  border-bottom: 1px dotted var(--line);
}

.research-list li:last-child { border-bottom: none; }

.research-title {
  display: inline-block;
  background: var(--tag-bg);
  color: var(--tag-text);
  padding: 0.22rem 0.65rem;
  border-radius: 4px;
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  margin-bottom: 0.45rem;
}

.research-desc {
  color: var(--text);
  font-size: 0.95rem;
  padding-left: 0.15rem;
}

/* News */
.news {
  list-style: none;
  padding: 0;
  margin: 0;
}

.news li {
  display: flex;
  gap: 0.85rem;
  padding: 0.55rem 0;
  align-items: start;
  font-size: 0.97rem;
  border-bottom: 1px dotted var(--line);
}

.news li:last-child { border-bottom: none; }

.news .date {
  flex: 0 0 auto;
  background: var(--tag-bg);
  color: var(--tag-text);
  padding: 0.22rem 0.55rem;
  border-radius: 4px;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  white-space: nowrap;
  margin-top: 0.1rem;
}

.news-body { flex: 1 1 auto; }

/* Publications */
.pub-author-note {
  margin: 0 0 0.75rem;
  color: var(--muted);
  font-size: 0.8rem;
}

.pub {
  display: grid;
  grid-template-columns: 6.5rem 1fr;
  gap: 1rem;
  padding: 0.75rem 0;
  border-bottom: 1px dotted var(--line);
  align-items: start;
}

.pub:last-child { border-bottom: none; }

.pub-tag {
  display: inline-block;
  background: var(--tag-bg);
  color: var(--tag-text);
  padding: 0.18rem 0.5rem;
  border-radius: 3px;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-align: center;
  white-space: nowrap;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

.pub-body { font-size: 0.97rem; }

.pub-title {
  font-weight: 600;
  color: var(--text);
  margin: 0 0 0.15rem;
}

.pub-authors {
  margin: 0 0 0.15rem;
  color: var(--text);
}

.pub-authors .me {
  font-weight: 700;
  text-decoration: underline;
}

.pub-authors sup {
  line-height: 0;
}

.pub-venue {
  color: var(--muted);
  font-style: italic;
  margin: 0 0 0.25rem;
}

.pub-links {
  font-size: 0.88rem;
  margin: 0;
}

.pub-links a { margin-right: 0.5rem; }

.pub-bibtex { display: inline; }

.pub-bibtex summary {
  display: inline;
  cursor: pointer;
  color: var(--link);
  list-style: none;
}

.pub-bibtex summary::-webkit-details-marker { display: none; }
.pub-bibtex summary::marker { content: ""; }
.pub-bibtex summary:hover { text-decoration: underline; }

.pub-bibtex pre {
  margin: 0.6rem 0 0;
  padding: 0.75rem 0.9rem;
  background: #f1f3f5;
  border: 1px solid var(--line);
  border-radius: 4px;
  font-size: 0.8rem;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  overflow-x: auto;
  white-space: pre;
  line-height: 1.5;
  color: #333;
}

/* Education / Experience / Projects entries */
.entry {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1rem;
  padding: 0.5rem 0;
  align-items: baseline;
  border-bottom: 1px dotted var(--line);
}

.entry:last-child { border-bottom: none; }

.entry-main { font-size: 0.97rem; }
.entry-role { color: var(--muted); font-size: 0.9rem; margin-top: 0.1rem; }
.entry-date {
  color: var(--muted);
  font-size: 0.9rem;
  font-variant-numeric: tabular-nums;
  white-space: nowrap;
}

/* Project entry link on main page (clickable title row) */
.entry .proj-link {
  color: var(--text);
  border-bottom: 1px dashed transparent;
  transition: border-color 0.15s, color 0.15s;
}
.entry .proj-link:hover {
  color: var(--link);
  border-bottom-color: var(--link);
  text-decoration: none;
}

.project-group-title {
  margin: 1.5rem 0 0.4rem;
  color: var(--muted);
  font-size: 0.9rem;
  font-weight: 600;
}

.project-group-title:first-of-type { margin-top: 0; }
.project-entry { padding: 1rem 0; }
.project-entry .entry-main { min-width: 0; }
.project-entry .proj-link { line-height: 1.5; word-break: keep-all; overflow-wrap: anywhere; }
.project-entry .entry-role { margin-top: 0.4rem; }
.project-entry .entry-summary { margin: 0.55rem 0 0; font-size: 0.92rem; }
.project-entry .entry-date small { display: block; font-size: 0.75rem; text-align: right; }

/* ===== Project detail pages ===== */

.project-header {
  display: block;
  margin: 0.5rem 0 2rem;
}

.project-facts { margin: 0 0 1rem; font-size: 0.95rem; }
.project-header .project-facts { margin-top: 1.25rem; }
.project-facts > div {
  display: grid;
  grid-template-columns: 7.5rem minmax(0, 1fr);
  gap: 0.75rem;
  padding: 0.55rem 0;
  border-bottom: 1px dotted var(--line);
}
.project-facts > div:last-child { border-bottom: none; }
.project-facts dt { color: var(--muted); font-weight: 600; }
.project-facts dd { margin: 0; overflow-wrap: anywhere; }

.project-meta {
  color: var(--muted);
  font-size: 0.88rem;
  margin: 0 0 0.4rem;
  font-variant-numeric: tabular-nums;
}

.project-meta .tag {
  display: inline-block;
  background: var(--tag-bg);
  color: var(--tag-text);
  padding: 0.18rem 0.5rem;
  border-radius: 3px;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.02em;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  margin-right: 0.5rem;
}

.project-title {
  font-size: 1.85rem;
  font-weight: 700;
  margin: 0 0 0.4rem;
  letter-spacing: -0.01em;
  word-break: keep-all;
  overflow-wrap: anywhere;
}

.project-subtitle {
  color: var(--muted);
  font-size: 1.02rem;
  margin: 0;
  line-height: 1.5;
}

.back-link {
  display: inline-block;
  font-size: 0.9rem;
  color: var(--muted);
  margin-top: 2.5rem;
}

.back-link:hover { color: var(--link); }

.placeholder {
  color: var(--muted);
  font-style: italic;
}

/* Project figures */
.project-figure {
  margin: 1rem 0 0.25rem;
  text-align: center;
}

.project-figure img {
  max-width: 100%;
  height: auto;
  border: 1px solid var(--line);
  border-radius: 4px;
  background: #fff;
  display: block;
  margin: 0 auto;
}

.project-figure figcaption {
  margin-top: 0.5rem;
  font-size: 0.85rem;
  color: var(--muted);
  font-style: italic;
  text-align: center;
}

.figure-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.75rem;
  margin: 1rem 0 0.25rem;
}

.figure-row .project-figure { margin: 0; }

@media (max-width: 560px) {
  .figure-row { grid-template-columns: 1fr; }
  .project-facts > div { grid-template-columns: 1fr; gap: 0.2rem; }
}

/* Footer */
footer {
  margin-top: 3.5rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.82rem;
  text-align: center;
}

@media (max-width: 720px) {
  main { padding: 1.75rem 1.25rem 3rem; }
  header { grid-template-columns: 1fr; }
  .photo { width: 140px; height: 170px; margin: 0 auto; }
  h1 { font-size: 1.6rem; }
  h1 .kr { font-size: 1.3rem; display: inline-block; }
  .pub { grid-template-columns: 1fr; gap: 0.3rem; }
  .pub-tag { justify-self: start; }
  .entry { grid-template-columns: 1fr; }
  .project-entry .entry-date small { display: inline; margin-left: 0.5rem; }
  .topnav { font-size: 0.88rem; }
  .project-title { font-size: 1.45rem; }
}