/* =============================================================================
   Namhyoung Kim · Personal Website
   Laid out like a research-group site: dark navigation bar, a title banner on
   every subpage, tinted section bands, numbered lists. Serif for reading,
   sans for navigation and labels, one navy accent taken from the PDF CV.
   ============================================================================= */

:root {
  --serif: 'Source Serif 4', 'Source Serif Pro', Georgia, 'Times New Roman', serif;
  --sans:  'Source Sans 3', 'Source Sans Pro', 'Noto Sans KR', 'Apple SD Gothic Neo', 'Helvetica Neue', Arial, sans-serif;
  /* Korean pages: Latin from Source Sans, Hangul from Noto Sans KR */
  --sans-ko: 'Source Sans 3', 'Noto Sans KR', 'Apple SD Gothic Neo', 'Malgun Gothic', sans-serif;

  --max-w: 980px;

  --bg:       #ffffff;
  --fg:       #1c1c1c;
  --fg-soft:  #464646;
  --fg-mute:  #6c6c6c;
  --line:     #e1e4e8;
  --accent:   #0b3b70;   /* navy of the CV headings */
  --accent-hi:#072a52;
  --band:     #eef2f6;
  --band-fg:  #0b3b70;
  --bar:      #0d2440;   /* navigation bar and banner */
  --bar-fg:   #ffffff;
  --bar-soft: #b9c6d6;
  --bar-hi:   #9fc0e6;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg:       #13161a;
    --fg:       #e6e6e6;
    --fg-soft:  #c3c6cb;
    --fg-mute:  #92979e;
    --line:     #2a2f36;
    --accent:   #a3c2e8;
    --accent-hi:#c8dbf2;
    --band:     #1b222b;
    --band-fg:  #c8dbf2;
    --bar:      #0a1a2e;
  }
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--serif);
  font-size: 17px;
  line-height: 1.62;
  font-variant-numeric: lining-nums;
  overflow-x: hidden;
}

.wrap {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

a       { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hi); text-decoration: underline; text-underline-offset: 2px; }

::selection { background: #d5e1ef; color: #1c1c1c; }

p, ul, ol { margin: 0 0 1em; }

/* ------------------------------------------------------- navigation bar -- */
.site-header {
  background: var(--bar);
  color: var(--bar-fg);
}
.site-header .wrap {
  display: flex;
  align-items: center;
  gap: 8px 24px;
  flex-wrap: wrap;
  min-height: 62px;
  padding-top: 10px;
  padding-bottom: 10px;
}
.site-title {
  font-family: var(--serif);
  font-weight: 700;
  font-size: 1.15rem;
  letter-spacing: 0.01em;
  color: var(--bar-fg);
}
.site-title:hover { color: var(--bar-fg); text-decoration: none; }

.site-nav {
  margin-left: auto;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  font-family: var(--sans);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.09em;
  text-transform: uppercase;
}
.site-nav a { color: var(--bar-soft); padding: 4px 0; }
.site-nav a + a::before {
  content: "·";
  display: inline-block;
  margin: 0 0.75em;
  color: #5d728c;
}
.site-nav a:hover  { color: var(--bar-fg); text-decoration: none; }
.site-nav a, .contact-line a, .footer-links a { white-space: nowrap; }
@media (max-width: 680px) {
  .site-nav { gap: 2px 16px; }
  .site-nav a + a::before { display: none; }
}
.site-nav a.active {
  color: var(--bar-fg);
  text-decoration: underline;
  text-decoration-color: var(--bar-hi);
  text-decoration-thickness: 2px;
  text-underline-offset: 7px;
}

/* language toggle: EN | 한국어, the current language filled */
.lang-switch {
  display: flex;
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 600;
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: 2px;
  white-space: nowrap;
}
.lang-switch > * { padding: 2px 9px; }
.lang-switch span[aria-current] { background: var(--bar-fg); color: var(--bar); }
.lang-switch a { color: var(--bar-soft); }
.lang-switch a:hover { color: var(--bar-fg); text-decoration: none; }

@media (max-width: 680px) {
  .site-title   { order: 1; }
  .lang-switch  { order: 2; margin-left: auto; }
  .site-nav     { order: 3; margin-left: 0; width: 100%; }
}

/* --------------------------------------------------------------- banner -- */
.banner {
  background: var(--bar);
  color: var(--bar-fg);
  border-top: 1px solid rgba(255, 255, 255, 0.10);
  padding: 40px 0 38px;
}
.banner-eyebrow {
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--bar-hi);
  margin: 0 0 6px;
}
.banner-title {
  font-family: var(--sans);
  font-size: 2.1rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  line-height: 1.15;
  color: var(--bar-fg);
  margin: 0;
}
.banner-lede {
  color: var(--bar-soft);
  margin: 10px 0 0;
  max-width: 640px;
}

/* ------------------------------------------------------- main / footer -- */
.site-main { padding: 0 0 72px; min-height: calc(100vh - 260px); }
.page      { padding-top: 30px; }
.home      { padding-top: 44px; }

.site-footer {
  border-top: 1px solid var(--line);
  padding: 28px 0 36px;
  font-family: var(--sans);
  font-size: 0.9rem;
  color: var(--fg-mute);
}
.site-footer .wrap {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 8px 32px;
}
.footer-id { display: flex; flex-direction: column; line-height: 1.5; }
.footer-id strong { color: var(--fg); font-weight: 700; }
.footer-links { text-align: right; }
.footer-links a { color: var(--fg-soft); }
.footer-links a + a::before {
  content: "·";
  display: inline-block;
  margin: 0 0.6em;
  color: var(--fg-mute);
}
.copy { grid-column: 1 / -1; margin: 10px 0 0; font-size: 0.82rem; }

@media (max-width: 680px) {
  .site-footer .wrap { grid-template-columns: 1fr; }
  .footer-links { text-align: left; }
}

/* ------------------------------------------------------------ headings -- */
h1, h2, h3 { line-height: 1.25; color: var(--fg); }

/* Section band: a tinted strip that runs the full width of the window. */
h2.band {
  font-family: var(--sans);
  font-size: 0.92rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--band-fg);
  background: var(--band);
  box-shadow: 0 0 0 100vmax var(--band);
  clip-path: inset(0 -100vmax);
  padding: 13px 0;
  margin: 52px 0 18px;
}
.page > h2.band:first-child { margin-top: 0; }
.legend + h2.band,
.intro + h2.band { margin-top: 28px; }

.band-note {
  font-family: var(--sans);
  font-size: 0.9rem;
  color: var(--fg-mute);
  margin: -4px 0 2px;
}

.legend {
  font-family: var(--sans);
  font-size: 0.92rem;
  color: var(--fg-mute);
  margin: 0 0 4px;
}
.legend strong { color: var(--fg); }

.intro {
  font-size: 1.08rem;
  color: var(--fg-soft);
  max-width: 720px;
  margin-bottom: 8px;
}

/* ---------------------------------------------------------------- home -- */
.hero {
  display: grid;
  grid-template-columns: 1fr 156px;
  grid-template-areas:
    "name    photo"
    "role    photo"
    "contact photo";
  column-gap: 36px;
  align-items: start;
}
.hero .avatar-wrap  { grid-area: photo; }
.hero h1            { grid-area: name; }
.hero .role         { grid-area: role; }
.hero .contact-line { grid-area: contact; }

.avatar-wrap { width: 156px; height: 156px; position: relative; }
button.avatar-wrap {
  display: block;
  border: 0;
  padding: 0;
  background: none;
  cursor: pointer;
}
button.avatar-wrap:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
.avatar-wrap img.avatar {
  position: absolute;
  inset: 0;
  width: 100%; height: 100%;
  object-fit: cover;
  border-radius: 2px;
  display: block;
}
.avatar-wrap .avatar-placeholder {
  width: 100%; height: 100%;
  border: 1px solid var(--line);
  color: var(--fg-mute);
  font-family: var(--sans);
  font-size: 0.75rem;
  display: flex; align-items: center; justify-content: center;
  text-align: center;
}

.hero h1 .name-alt {
  font-size: 1.05rem;
  font-weight: 400;
  color: var(--fg-mute);
  margin-left: 10px;
  letter-spacing: 0;
}
.hero h1 {
  font-size: 2.3rem;
  font-weight: 700;
  color: var(--accent);
  margin: 6px 0 8px;
}
.hero .role { color: var(--fg-soft); line-height: 1.55; margin-bottom: 12px; }
.hero .role a { color: var(--fg); }
.hero .role a:hover { color: var(--accent); }

.contact-line { font-family: var(--sans); font-size: 0.95rem; margin: 0; }
.contact-line a + a::before {
  content: "·";
  display: inline-block;
  margin: 0 0.55em;
  color: var(--fg-mute);
}

.bio { max-width: 720px; margin-top: 30px; }
.bio strong { font-weight: 600; }

.counts {
  list-style: none;
  padding: 0;
  margin: 26px 0 0;
  display: flex;
  flex-wrap: wrap;
  font-family: var(--sans);
  font-size: 0.92rem;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.counts li { padding: 10px 0; }
.counts li + li { margin-left: 22px; padding-left: 22px; border-left: 1px solid var(--line); }
.counts a { color: var(--fg-soft); }
.counts a:hover { color: var(--accent); }
.counts strong {
  font-family: var(--serif);
  font-size: 1.2rem;
  color: var(--accent);
  margin-right: 4px;
}

@media (max-width: 680px) {
  body { font-size: 16.5px; }
  .hero {
    grid-template-columns: 1fr;
    grid-template-areas: "photo" "name" "role" "contact";
  }
  .avatar-wrap { width: 120px; height: 120px; margin-bottom: 14px; }
  .hero .contact-line { display: flex; flex-wrap: wrap; gap: 2px 16px; }
  .hero .contact-line a + a::before { display: none; }
  .counts { flex-direction: column; }
  .counts li + li { margin-left: 0; padding-left: 0; border-left: 0; border-top: 1px solid var(--line); }
  .banner-title { font-size: 1.7rem; }
}

/* the second photo fades in and out over the first: 3.5 s each */
.avatar-wrap img.avatar-alt {
  opacity: 0;
  animation: avatar-swap 7s ease-in-out infinite;
}
@keyframes avatar-swap {
  0%, 40%  { opacity: 0; }
  50%, 90% { opacity: 1; }
  100%     { opacity: 0; }
}
@media (prefers-reduced-motion: reduce) {
  .avatar-wrap img.avatar-alt { animation: none; }
}
/* with JavaScript the swap is driven by a class, so a click can flip it */
.avatar-wrap.js img.avatar-alt { animation: none; transition: opacity 0.5s ease-in-out; }
.avatar-wrap.js.show-alt img.avatar-alt { opacity: 1; }

/* news */
.news-list { list-style: none; padding: 0; margin: 0; }
.news-list li {
  display: grid;
  grid-template-columns: 84px 1fr;
  gap: 18px;
  padding: 6px 0;
  align-items: baseline;
}
.news-list .item { font-size: 0.98rem; }
.news-list .date {
  font-family: var(--sans);
  font-size: 0.88rem;
  color: var(--fg-mute);
  font-variant-numeric: tabular-nums;
}
@media (max-width: 680px) {
  .news-list li { grid-template-columns: 1fr; gap: 0; padding: 8px 0; }
}

.see-all { font-family: var(--sans); font-size: 0.95rem; margin-top: 12px; }

/* ------------------------------------------------- publication entries -- */
.pub-list { list-style: none; padding: 0; margin: 0; }

.pub {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 12px;
  padding: 14px 0;
}
.pub + .pub { border-top: 1px solid var(--line); }
.pub-compact { grid-template-columns: 104px 1fr; gap: 16px; padding: 11px 0; }

.pub-num {
  font-family: var(--sans);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}
.pub-label {
  font-family: var(--sans);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--accent);
  white-space: nowrap;
}

.pub-title { font-weight: 600; line-height: 1.4; }
.pub-title a { color: var(--fg); }
.pub-title a:hover { color: var(--accent); }

.pub-authors { color: var(--fg-soft); font-size: 0.96rem; margin-top: 2px; }
.pub-authors strong { color: var(--fg); font-weight: 700; }

.pub-venue { color: var(--fg-soft); font-size: 0.94rem; }
.pub-note  { color: var(--fg-mute); }

.pub-tags {
  font-family: var(--sans);
  font-size: 0.82rem;
  color: var(--fg-mute);
  margin-top: 5px;
}
.pub-tags span { display: inline-block; margin-right: 0.9em; }

.pub-links { font-family: var(--sans); font-size: 0.82rem; margin-top: 7px; }
.pub-links a {
  display: inline-block;
  padding: 1px 8px;
  margin-right: 6px;
  border: 1px solid var(--line);
  border-radius: 2px;
  color: var(--fg-soft);
}
.pub-links a:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }
.pub-body { min-width: 0; }

/* BibTeX: a chip like the links above, opening a small code box with a copy button */
.bib-toggle, .bib-copy {
  font: inherit;
  font-family: var(--sans);
  font-size: 0.82rem;
  line-height: 1.5;
  padding: 1px 8px;
  border: 1px solid var(--line);
  border-radius: 2px;
  background: none;
  color: var(--fg-soft);
  cursor: pointer;
}
.bib-toggle:hover, .bib-copy:hover { border-color: var(--accent); color: var(--accent); }
.bib-toggle[aria-expanded="true"] { border-color: var(--accent); color: var(--accent); }
.bib {
  position: relative;
  margin-top: 8px;
}
.bib pre {
  margin: 0;
  padding: 10px 12px;
  padding-right: 72px;
  background: var(--band);
  border: 1px solid var(--line);
  border-radius: 2px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.76rem;
  line-height: 1.5;
  overflow-x: auto;
  white-space: pre;
}
.bib .bib-copy {
  position: absolute;
  top: 8px;
  right: 8px;
  background: var(--bg);
}

.pub:target { background: var(--band); box-shadow: 0 0 0 10px var(--band); }

@media (max-width: 680px) {
  .pub, .pub-compact { grid-template-columns: 1fr; gap: 2px; }
}

/* ------------------------------------------------------- research areas -- */
.area {
  display: grid;
  grid-template-columns: 5fr 7fr;
  gap: 40px;
  padding: 30px 0;
  border-top: 1px solid var(--line);
}
.intro + .area { margin-top: 26px; }
.area h2 {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--accent);
  margin: 0 0 10px;
}
.area-text p { color: var(--fg-soft); margin: 0; }
.area h3 {
  font-family: var(--sans);
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--fg-mute);
  margin: 4px 0 8px;
}
.area h3 + .related { margin-bottom: 0; }
.related + h3 { margin-top: 20px; }
.related { list-style: none; padding: 0; }
.related li {
  display: grid;
  grid-template-columns: 96px 1fr;
  gap: 12px;
  padding: 4px 0;
  font-size: 0.96rem;
  line-height: 1.45;
}
.related-label {
  font-family: var(--sans);
  font-size: 0.82rem;
  font-weight: 700;
  color: var(--fg-mute);
  white-space: nowrap;
  padding-top: 2px;
}
.related a { color: var(--fg); }
.related a:hover { color: var(--accent); }

/* one small figure per area, cropped from the paper, under the description */
.area-fig { margin: 18px 0 0; }
.area-fig a { display: block; }
.area-fig img {
  display: block;
  width: 100%;
  height: auto;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 2px;
  padding: 6px;
  box-sizing: border-box;
}
.area-fig figcaption {
  margin-top: 6px;
  font-family: var(--sans);
  font-size: 0.8rem;
  color: var(--fg-mute);
}

@media (max-width: 760px) {
  .area { grid-template-columns: 1fr; gap: 16px; }
  .area-fig { max-width: 420px; }
}

/* ------------------------------------------------------------- projects -- */
.projects {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0 40px;
}
.project {
  padding: 18px 0 20px;
  border-bottom: 1px solid var(--line);
}
.project-sponsor {
  font-family: var(--sans);
  font-size: 0.86rem;
  font-weight: 700;
  color: var(--accent);
  margin: 0 0 4px;
}
.project-title { font-size: 1.05rem; font-weight: 600; line-height: 1.4; margin: 0 0 6px; }
.project-desc  { color: var(--fg-soft); font-size: 0.95rem; margin: 0 0 8px; }
.project-meta  {
  font-family: var(--sans);
  font-size: 0.86rem;
  color: var(--fg-mute);
  margin: 0;
  font-variant-numeric: tabular-nums;
}
.project:target { background: var(--band); box-shadow: 0 0 0 10px var(--band); }

@media (max-width: 760px) {
  .projects { grid-template-columns: 1fr; }
}

/* ------------------------------------------------------------------- cv -- */
.cv-entry {
  display: grid;
  grid-template-columns: 150px 1fr;
  gap: 20px;
  padding: 7px 0;
}
.cv-entry .when {
  font-family: var(--sans);
  font-size: 0.9rem;
  color: var(--fg-mute);
  font-variant-numeric: tabular-nums;
  padding-top: 2px;
}
.cv-entry .title { font-weight: 600; line-height: 1.4; }
.cv-entry .title a { color: var(--fg); }
.cv-entry .title a:hover { color: var(--accent); }
.cv-entry .where { color: var(--fg-soft); font-size: 0.95rem; }
.cv-entry .desc  { color: var(--fg-soft); font-size: 0.94rem; margin: 2px 0 0; padding-left: 18px; }

@media (max-width: 680px) {
  .cv-entry { grid-template-columns: 1fr; gap: 0; }
}

/* ----------------------------------------------------------------- misc -- */
hr { border: 0; border-top: 1px solid var(--line); margin: 2em 0; }
code {
  font-size: 0.88em;
  background: var(--band);
  padding: 0.1em 0.35em;
  border-radius: 2px;
}

/* --------------------------------------------------------- korean pages -- */
html[lang="ko"] body {
  font-family: var(--sans-ko);
  font-size: 16.5px;
  line-height: 1.75;
  word-break: keep-all;
  overflow-wrap: break-word;
}
html[lang="ko"] .site-title,
html[lang="ko"] .counts strong { font-family: var(--sans-ko); margin: 0 1px 0 0; }
html[lang="ko"] .site-nav      { letter-spacing: 0.04em; font-size: 0.86rem; }
html[lang="ko"] .banner-title  { letter-spacing: 0; }
html[lang="ko"] .banner-eyebrow{ letter-spacing: 0.08em; }
html[lang="ko"] h2.band        { letter-spacing: 0.02em; font-size: 0.98rem; }
html[lang="ko"] .area h3       { letter-spacing: 0.02em; font-size: 0.84rem; }
html[lang="ko"] .pub-title,
html[lang="ko"] .project-title,
html[lang="ko"] .cv-entry .title { font-weight: 700; }
html[lang="ko"] .pub-venue em  { font-style: normal; }