/* ============================================
   Academic Portfolio
   Aesthetic: clean white, professional, modern
   ============================================ */

:root {
  /* Color - pure white base, cool greys */
  --bg:           #FFFFFF;
  --bg-alt:       #F7F8FA;
  --bg-card:      #FFFFFF;
  --ink:          #0F172A;
  --ink-soft:     #1E293B;
  --muted:        #64748B;
  --light:        #94A3B8;
  --border:       #E5E7EB;
  --border-soft:  #F1F2F4;
  --accent:       #2563EB;
  --accent-soft:  #DBEAFE;
  --link:         #2563EB;
  --highlight-bg: #F7F8FA;

  /* Type */
  --serif:  'Fraunces', 'Times New Roman', Georgia, serif;
  --sans:   'Geist', 'Pretendard Variable', 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --mono:   'JetBrains Mono', 'SF Mono', Menlo, monospace;

  /* Layout */
  --max-w: 920px;
  --nav-h: 60px;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-h) + 24px);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

body {
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 15.5px;
  line-height: 1.65;
  font-feature-settings: 'ss01', 'cv11';
}

a { color: var(--link); text-decoration: none; transition: color .15s ease, border-color .15s ease; }
a:hover { color: var(--ink); }

/* ============================================
   Top Navigation
   ============================================ */
.top-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-h);
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--border-soft);
  z-index: 50;
}

.nav-inner {
  max-width: var(--max-w);
  height: 100%;
  margin: 0 auto;
  padding: 0 32px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-name {
  font-family: var(--sans);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.nav-links {
  list-style: none;
  display: flex;
  gap: 26px;
}

.nav-links a {
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0;
  color: var(--muted);
  border-bottom: 1px solid transparent;
  padding-bottom: 2px;
  text-transform: none;
}
.nav-links a:hover { color: var(--ink); border-bottom-color: var(--ink); }

@media (max-width: 720px) {
  .nav-links { gap: 14px; }
  .nav-links a { font-size: 12px; }
  .nav-name { font-size: 14px; }
}

/* ============================================
   Layout
   ============================================ */
main {
  position: relative;
  z-index: 1;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: calc(var(--nav-h) + 48px) 32px 80px;
}

section {
  padding: 48px 0;
  border-top: 1px solid var(--border-soft);
}

section:first-of-type { border-top: none; padding-top: 16px; }

.section-label {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin-bottom: 28px;
}

.section-label h2 {
  font-family: var(--sans);
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.section-label .num {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--light);
  letter-spacing: 0.08em;
  font-weight: 400;
}

/* ============================================
   Hero / About
   ============================================ */
.hero {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 48px;
  align-items: start;
  padding: 24px 0 56px;
  border-top: none;
}

.hero-text { order: 2; }
.profile-wrap { order: 1; }

.hero-text h1 {
  font-family: var(--sans);
  font-size: 38px;
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.025em;
  margin-bottom: 6px;
  color: var(--ink);
}

.hero-text h1 em {
  font-style: normal;
  font-weight: 600;
}

.korean-name {
  font-family: var(--sans);
  font-size: 14px;
  font-weight: 400;
  color: var(--muted);
  margin-bottom: 18px;
  letter-spacing: 0;
}

.affiliation {
  font-size: 14px;
  color: var(--ink-soft);
  margin-bottom: 3px;
}

.affiliation strong {
  font-weight: 600;
}

.location {
  font-size: 13.5px;
  color: var(--muted);
  margin-bottom: 22px;
}

.bio {
  font-size: 14.5px;
  line-height: 1.7;
  color: var(--ink-soft);
  margin-bottom: 14px;
  max-width: 64ch;
}

.bio + .bio { margin-top: 12px; }

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

.interests {
  margin-top: 20px;
  padding-top: 16px;
  border-top: 1px solid var(--border-soft);
  font-size: 12.5px;
  font-family: var(--sans);
  color: var(--muted);
  letter-spacing: 0;
  line-height: 1.85;
}

.interests .label {
  color: var(--ink);
  font-weight: 600;
  text-transform: uppercase;
  font-size: 10.5px;
  letter-spacing: 0.1em;
  margin-right: 12px;
  font-family: var(--mono);
}

.interests span.tag {
  display: inline-block;
  margin-right: 4px;
  color: var(--ink-soft);
}

.interests span.tag::after {
  content: '·';
  margin-left: 8px;
  color: var(--light);
}
.interests span.tag:last-child::after { content: ''; }

.profile-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.profile-photo {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  object-fit: cover;
  display: block;
}

.profile-photo.placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--sans);
  font-size: 44px;
  font-weight: 300;
  color: var(--light);
  background: var(--bg-alt);
}

.quick-links {
  display: flex;
  flex-direction: column;
  gap: 4px;
  width: 100%;
  max-width: 180px;
}

.quick-links a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 12.5px;
  padding: 7px 12px;
  color: var(--ink-soft);
  border: 1px solid var(--border);
  background: var(--bg-card);
  font-family: var(--sans);
  font-weight: 500;
  letter-spacing: 0;
  border-radius: 6px;
}

.quick-links a:hover {
  border-color: var(--ink);
  color: var(--ink);
  background: var(--bg-alt);
}

.quick-links .arrow {
  color: var(--light);
  font-size: 11px;
  transition: transform .15s ease;
}
.quick-links a:hover .arrow { transform: translateX(2px); color: var(--ink); }

/* ============================================
   Info Row (Contact + Education)
   ============================================ */
.info-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 32px;
  margin-top: 24px;
  padding-top: 22px;
  border-top: 1px solid var(--border-soft);
}

.info-col {
  display: flex;
  flex-direction: column;
}

.info-heading {
  font-family: var(--mono);
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink);
  margin-bottom: 16px;
  padding-bottom: 10px;
}

.info-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.info-list li {
  font-size: 13.5px;
  line-height: 1.55;
  color: var(--ink-soft);
}

.info-label {
  display: inline-block;
  font-family: var(--mono);
  font-size: 10.5px;
  color: var(--muted);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  font-weight: 500;
  min-width: 60px;
  margin-right: 8px;
}

.info-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--ink);
  line-height: 1.4;
  margin-bottom: 3px;
}

.info-sub {
  font-size: 12.5px;
  color: var(--muted);
  font-family: var(--mono);
  letter-spacing: 0;
  margin-bottom: 2px;
}

.info-meta {
  font-size: 12.5px;
  color: var(--muted);
}

@media (max-width: 720px) {
  .info-row {
    grid-template-columns: 1fr;
    gap: 28px;
  }
}

/* ============================================
   Publications
   ============================================ */
.pub-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.pub {
  display: grid;
  grid-template-columns: 64px 1fr;
  gap: 24px;
  align-items: start;
}

.pub-year {
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--ink);
  letter-spacing: 0.04em;
  padding-top: 4px;
  padding-right: 12px;
  text-align: right;
  font-weight: 500;
  border-right: 1px solid var(--border-soft);
}

.pub-year .month {
  display: block;
  color: var(--light);
  font-size: 10.5px;
  margin-top: 2px;
  font-weight: 400;
}

.pub-body .pub-title {
  font-family: var(--sans);
  font-size: 16px;
  font-weight: 600;
  line-height: 1.4;
  letter-spacing: -0.01em;
  color: var(--ink);
  margin-bottom: 6px;
}

.pub-authors {
  font-size: 13.5px;
  color: var(--muted);
  line-height: 1.55;
  margin-bottom: 5px;
}

.pub-authors .me {
  color: var(--ink);
  font-weight: 600;
  border-bottom: 1px solid var(--accent);
}

.pub-venue {
  font-size: 13px;
  color: var(--ink-soft);
  margin-bottom: 10px;
  font-style: normal;
  font-family: var(--sans);
  font-weight: 500;
}

.pub-venue .if {
  font-family: var(--mono);
  font-size: 10.5px;
  color: var(--muted);
  margin-left: 8px;
  letter-spacing: 0.04em;
  font-weight: 400;
}

.pub-tags {
  font-size: 11.5px;
  font-family: var(--mono);
  color: var(--muted);
  margin-bottom: 10px;
  line-height: 1.7;
}

.pub-tags span {
  display: inline-block;
}
.pub-tags span::after {
  content: '·';
  margin: 0 6px;
  color: var(--light);
}
.pub-tags span:last-child::after { content: ''; }

.pub-highlight {
  font-size: 13px;
  color: var(--ink-soft);
  background: var(--bg-alt);
  padding: 10px 14px;
  border-left: 2px solid var(--accent);
  margin-bottom: 12px;
  line-height: 1.55;
  border-radius: 0 4px 4px 0;
}

.pub-links {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.pub-links a {
  font-size: 11.5px;
  font-family: var(--sans);
  font-weight: 500;
  letter-spacing: 0;
  padding: 4px 10px;
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--muted);
  background: var(--bg-card);
}
.pub-links a:hover {
  background: var(--ink);
  color: var(--bg);
  border-color: var(--ink);
}

/* ============================================
   Projects
   ============================================ */
.project-grid {
  display: flex;
  flex-direction: column;
  gap: 0;
  border-top: 1px solid var(--border-soft);
}

.project-card {
  display: grid;
  grid-template-columns: 90px 1fr auto;
  gap: 24px;
  padding: 20px 4px;
  border-bottom: 1px solid var(--border-soft);
  align-items: start;
  text-decoration: none;
  color: var(--ink);
  transition: background .15s ease, padding-left .15s ease;
}

.project-card:hover {
  background: var(--bg-alt);
  padding-left: 12px;
  color: var(--ink);
}

.project-card:hover .project-arrow {
  transform: translateX(4px);
  color: var(--ink);
}

.project-card:hover .project-title {
  color: var(--accent);
}

.project-date {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--muted);
  letter-spacing: 0.02em;
  padding-top: 4px;
  font-weight: 500;
}

.project-body .lead-tag {
  display: inline-block;
  font-family: var(--mono);
  font-size: 9.5px;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 2px 6px;
  letter-spacing: 0.1em;
  margin-right: 8px;
  vertical-align: middle;
  font-weight: 600;
  border-radius: 3px;
}

.project-title {
  font-family: var(--sans);
  font-size: 15px;
  font-weight: 600;
  line-height: 1.4;
  letter-spacing: -0.005em;
  margin-bottom: 4px;
  color: var(--ink);
  transition: color .15s ease;
}

.project-funder {
  font-size: 12px;
  color: var(--muted);
  font-family: var(--mono);
  letter-spacing: 0;
}

.project-desc {
  font-size: 13px;
  color: var(--muted);
  margin-top: 6px;
  line-height: 1.55;
  max-width: 60ch;
}

.project-arrow {
  font-family: var(--sans);
  font-size: 18px;
  color: var(--light);
  align-self: center;
  padding-right: 4px;
  transition: transform .15s ease, color .15s ease;
}

/* ============================================
   Education + Experience
   ============================================ */
.entry-group + .entry-group {
  margin-top: 36px;
}

.entry-group-label {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink);
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--border-soft);
}

.entry-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.entry {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 28px;
  align-items: start;
}

.entry-date {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--muted);
  letter-spacing: 0.02em;
  padding-top: 4px;
  line-height: 1.5;
  font-weight: 500;
}

.entry-title {
  font-family: var(--sans);
  font-size: 15px;
  font-weight: 600;
  line-height: 1.4;
  letter-spacing: -0.005em;
  margin-bottom: 3px;
  color: var(--ink);
}

.entry-org {
  font-size: 13px;
  color: var(--muted);
  margin-bottom: 8px;
  font-family: var(--sans);
}

.entry-details {
  font-size: 13.5px;
  color: var(--ink-soft);
  line-height: 1.65;
}

.entry-details ul {
  list-style: none;
  margin-top: 4px;
}
.entry-details ul li {
  padding-left: 14px;
  position: relative;
  margin-bottom: 4px;
}
.entry-details ul li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 9px;
  width: 4px;
  height: 4px;
  background: var(--light);
  border-radius: 50%;
}

/* ============================================
   Awards
   ============================================ */
.award-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.award {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 28px;
  align-items: baseline;
}

.award-date {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--muted);
  letter-spacing: 0.02em;
  font-weight: 500;
}

.award-title {
  font-size: 14.5px;
  font-weight: 600;
  color: var(--ink);
  margin-bottom: 3px;
}

.award-org {
  font-size: 13px;
  color: var(--muted);
}

.award-note {
  font-size: 12.5px;
  color: var(--muted);
  margin-top: 4px;
  font-style: normal;
}

/* ============================================
   Skills
   ============================================ */
.skills-grid {
  display: grid;
  grid-template-columns: 140px 1fr;
  gap: 28px 28px;
  row-gap: 14px;
  align-items: baseline;
}

.skill-label {
  font-family: var(--mono);
  font-size: 11px;
  color: var(--ink);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
}

.skill-items {
  font-family: var(--sans);
  font-size: 13.5px;
  color: var(--ink-soft);
  letter-spacing: 0;
  font-weight: 500;
}

.skill-items span {
  display: inline-block;
}

.skill-items span::after {
  content: '·';
  margin: 0 8px;
  color: var(--light);
}
.skill-items span:last-child::after { content: ''; }

/* ============================================
   Footer
   ============================================ */
footer {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 32px 32px 48px;
  border-top: 1px solid var(--border-soft);
  font-size: 12px;
  font-family: var(--mono);
  color: var(--light);
  display: flex;
  justify-content: space-between;
  align-items: center;
  letter-spacing: 0.02em;
}

footer a {
  color: var(--muted);
}
footer a:hover { color: var(--ink); }

/* ============================================
   Project Detail Page
   ============================================ */
.detail-main {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: calc(var(--nav-h) + 48px) 32px 80px;
}

.back-link {
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--muted);
  letter-spacing: 0.04em;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-bottom: 36px;
  text-transform: uppercase;
  font-weight: 500;
}
.back-link:hover { color: var(--ink); }

.detail-header {
  margin-bottom: 40px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--border);
}

.detail-meta {
  display: flex;
  gap: 18px;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--muted);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 16px;
  font-weight: 500;
}

.detail-meta .sep { color: var(--light); }

.detail-title {
  font-family: var(--sans);
  font-size: 36px;
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.025em;
  margin-bottom: 14px;
  color: var(--ink);
}

.detail-subtitle {
  font-size: 15px;
  color: var(--muted);
  line-height: 1.6;
  max-width: 60ch;
}

.detail-section {
  margin-bottom: 40px;
}

.detail-section h3 {
  font-family: var(--sans);
  font-size: 18px;
  font-weight: 600;
  font-style: normal;
  margin-bottom: 14px;
  letter-spacing: -0.01em;
  color: var(--ink);
}

.detail-section p {
  font-size: 14.5px;
  line-height: 1.75;
  color: var(--ink-soft);
  margin-bottom: 12px;
  max-width: 65ch;
}

.detail-section ul {
  list-style: none;
  margin: 14px 0;
}

.detail-section ul li {
  padding-left: 18px;
  position: relative;
  margin-bottom: 8px;
  font-size: 14px;
  line-height: 1.7;
  max-width: 65ch;
  color: var(--ink-soft);
}
.detail-section ul li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 11px;
  width: 5px;
  height: 5px;
  background: var(--accent);
  border-radius: 50%;
}

.detail-aside {
  background: var(--bg-alt);
  padding: 22px 26px;
  margin: 22px 0;
  border-left: 3px solid var(--accent);
  border-radius: 0 6px 6px 0;
}

.detail-aside .aside-label {
  font-family: var(--mono);
  font-size: 10.5px;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 8px;
  display: block;
  font-weight: 600;
}

.tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 14px 0;
}

.tech-tags .tag {
  font-family: var(--mono);
  font-size: 10.5px;
  padding: 4px 9px;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  color: var(--muted);
  letter-spacing: 0.02em;
  border-radius: 4px;
}

/* Result tables */
.result-table {
  width: 100%;
  max-width: 560px;
  border-collapse: collapse;
  margin: 14px 0 22px;
  font-size: 13.5px;
}

.result-table caption {
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
  text-align: left;
  margin-bottom: 8px;
}

.result-table th,
.result-table td {
  padding: 8px 14px;
  text-align: left;
  border-bottom: 1px solid var(--border);
  color: var(--ink-soft);
}

.result-table thead th {
  font-family: var(--mono);
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.03em;
  text-transform: uppercase;
  color: var(--muted);
  background: var(--bg-alt);
}

.result-table .num {
  text-align: right;
  font-family: var(--mono);
  font-variant-numeric: tabular-nums;
}

.result-table tbody tr:last-child td {
  border-bottom: none;
}

.result-table tbody tr.total td {
  font-weight: 600;
  color: var(--ink);
  border-top: 1px solid var(--border);
}

/* Figure grid */
.figure-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  margin: 24px 0;
}

.figure-grid figure { margin: 0; }

.figure-grid img {
  width: 100%;
  border-radius: 8px;
  border: 1px solid var(--border);
  display: block;
}

.figure-grid figcaption {
  margin-top: 7px;
  color: var(--muted);
  font-size: 0.82em;
  text-align: center;
}

@media (max-width: 640px) {
  .figure-grid { grid-template-columns: 1fr; }
}

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 720px) {
  main { padding: calc(var(--nav-h) + 28px) 20px 60px; }
  .hero {
    grid-template-columns: 1fr;
    gap: 28px;
  }
  .hero-text h1 { font-size: 32px; }
  .profile-wrap { align-items: flex-start; }
  .profile-photo { width: 120px; height: 120px; }
  .quick-links { max-width: 240px; }

  .pub { grid-template-columns: 1fr; gap: 8px; }
  .pub-year {
    border-right: none;
    border-bottom: 1px solid var(--border-soft);
    text-align: left;
    padding: 0 0 8px 0;
  }

  .project-card { grid-template-columns: 1fr auto; gap: 12px; padding: 18px 4px; }
  .project-card:hover { padding-left: 4px; }
  .project-date { grid-column: 1 / -1; padding-top: 0; margin-bottom: 4px; }

  .entry, .award {
    grid-template-columns: 1fr;
    gap: 4px;
  }

  .skills-grid { grid-template-columns: 1fr; gap: 4px 0; }
  .skill-label { margin-top: 12px; }

  .detail-main { padding: calc(var(--nav-h) + 28px) 20px 60px; }
  .detail-title { font-size: 28px; }

  footer {
    flex-direction: column;
    align-items: flex-start;
    gap: 8px;
  }
}

/* ============================================
   Selection
   ============================================ */
::selection {
  background: var(--accent-soft);
  color: var(--ink);
}