:root {
  --bg: #f3f3f5;
  --ink: #111114;
  --ink2: #3a3a40;
  --muted: #4b4b55;
  --soft: #7c7d8a;
  --rule: rgba(0,0,0,0.1);
  --glass-bg: rgba(255,255,255,0.62);
  --glass-border: rgba(255,255,255,0.85);
  --glass-shadow: 0 6px 28px rgba(17,17,20,0.07), 0 1px 0 rgba(255,255,255,0.7) inset;
  --wrap: 1120px;
  --ease: cubic-bezier(0.2, 0.8, 0.2, 1);
  --serif: Georgia, 'Times New Roman', serif;
  --mono: 'Inter', 'Pretendard Variable', 'Pretendard', -apple-system, BlinkMacSystemFont, 'Apple SD Gothic Neo', sans-serif;
  --accent: #c2683f;     /* terracotta (warm) */
  --accent-2: #3e5a3e;   /* sage (cool) */
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 106%; }

body {
  margin: 0;
  font-family: 'Inter', 'Pretendard Variable', 'Pretendard', -apple-system, BlinkMacSystemFont, 'Apple SD Gothic Neo', sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
img { display: block; max-width: 100%; }

/* ── Glass mixin ── */
.glass {
  background: var(--glass-bg);
  backdrop-filter: blur(22px) saturate(160%);
  -webkit-backdrop-filter: blur(22px) saturate(160%);
  border: 1px solid var(--glass-border);
  box-shadow: var(--glass-shadow);
}

/* ── Top nav bar ── */
.top-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  border-radius: 0;
  border-left: none; border-right: none; border-top: none;
}
.top-nav-inner {
  width: min(var(--wrap), calc(100% - 44px));
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 24px;
  padding: 12px 0;
}
.top-nav-brand {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.02rem;
  letter-spacing: -0.01em;
  white-space: nowrap;
}
.site-nav {
  display: flex;
  flex-wrap: nowrap;
  gap: 2px;
  flex: 1;
  min-width: 0;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
.site-nav a {
  display: inline-flex; align-items: center;
  padding: 7px 12px;
  border-radius: 8px;
  font-size: 0.9rem;
  color: var(--muted);
  white-space: nowrap;
  transition: color 0.2s ease, background 0.2s ease;
}
.site-nav a:hover { color: var(--ink); background: rgba(0,0,0,0.04); }
.site-nav a.active { color: var(--accent); font-weight: 600; }

/* ── Page + layout ── */
.page {
  position: relative;
  z-index: 1;
  width: min(var(--wrap), calc(100% - 44px));
  margin: 0 auto;
  padding: 40px 0 40px;
}

.layout {
  display: grid;
  grid-template-columns: 330px minmax(0, 1fr);
  gap: 40px;
  align-items: start;
}

/* ── Sidebar / profile card ── */
.sidebar {
  position: sticky;
  top: 24px;
}

.profile-card {
  border-radius: 24px;
  padding: 24px 24px 26px;
  position: relative;
}

.profile-image {
  width: 84%;
  max-width: 100%;
  margin: 0 auto 20px;
  aspect-ratio: 4 / 5;
  border-radius: 16px;
  overflow: hidden;
  position: relative;
  border: 1px solid rgba(255,255,255,0.7);
  box-shadow: 0 4px 20px rgba(0,0,0,0.10);
  background: rgba(255,255,255,0.4);
  perspective: 1400px;
}
.flip-inner {
  position: absolute; inset: 0;
  transform-style: preserve-3d;
  transition: transform 0.7s cubic-bezier(0.4, 0, 0.2, 1);
}
.profile-image:hover .flip-inner { transform: rotateY(180deg); }
.profile-image .pf {
  position: absolute; inset: 0;
  width: 100%; height: 100%; object-fit: cover;
  backface-visibility: hidden;
}
.profile-image .pf-base { transform: rotateY(0deg); }
.profile-image .pf-alt { transform: rotateY(180deg); }

.flip-badge {
  position: absolute; right: 10px; bottom: 10px; z-index: 5;
  width: 28px; height: 28px; border-radius: 50%;
  background: rgba(17,17,20,0.55);
  display: flex; align-items: center; justify-content: center;
  color: #fff; pointer-events: none;
  animation: flipPulse 2.4s ease-in-out infinite;
}
.flip-badge svg { width: 14px; height: 14px; }
@keyframes flipPulse {
  0%, 100% { transform: scale(1); opacity: 0.82; }
  50% { transform: scale(1.14); opacity: 1; }
}
.profile-image:hover .flip-badge { opacity: 0; transition: opacity 0.15s ease; }
.profile-fallback {
  width: 100%; height: 100%;
  display: flex; align-items: center; justify-content: center;
  color: var(--soft); font-size: 0.8rem;
  font-family: var(--mono);
}

.name {
  margin: 0 0 5px;
  font-family: var(--serif);
  font-size: 1.6rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.1;
}
.role { margin: 0; font-size: 1rem; font-weight: 600; color: var(--ink2); }
.org  { margin: 3px 0 0; font-size: 0.92rem; color: var(--muted); line-height: 1.45; }

.divider { height: 1px; margin: 20px 0; background: var(--rule); }

.side-label {
  margin: 0 0 11px;
  font-family: var(--mono);
  font-size: 0.78rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--ink2);
}

.side-list { display: grid; gap: 7px; }
.side-list > div {
  font-size: 0.95rem;
  color: var(--ink2);
  padding-left: 13px;
  position: relative;
}
.side-list > div::before {
  content: "";
  position: absolute;
  left: 0; top: 0.65em;
  width: 6px; height: 1px;
  background: var(--soft);
}

.contact-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 8px; }
.contact-list a {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 0.96rem; color: var(--ink2);
  transition: color 0.18s ease, transform 0.18s ease;
}
.contact-list a:hover { color: var(--ink); transform: translateX(2px); }
.c-ico {
  display: inline-flex; align-items: center; justify-content: center;
  flex-shrink: 0; width: 15px; height: 15px;
  color: var(--soft);
  transition: color 0.18s ease;
}
.c-ico svg { width: 100%; height: 100%; display: block; }
.contact-list a:hover .c-ico { color: var(--ink); }

.cv-btn {
  display: block; width: 100%; text-align: center;
  padding: 11px 0; border-radius: 10px;
  background: var(--ink); color: #fff;
  font-size: 0.8rem; font-weight: 600; letter-spacing: 0.03em;
  transition: opacity 0.18s, transform 0.18s;
}
.cv-btn:hover { opacity: 0.85; transform: translateY(-1px); }

/* ── Main content ── */
.content { min-width: 0; }

.section { margin-bottom: 16px; }

.section-card { border-radius: 22px; padding: 32px 36px; position: relative; }

/* AR detection brackets + label on hover (cards) */
.section-card::before, .profile-card::before {
  content: ""; position: absolute; inset: 9px; border-radius: 12px;
  border: 1.5px solid var(--accent);
  opacity: 0; pointer-events: none;
  transition: opacity 0.25s var(--ease), inset 0.25s var(--ease);
  -webkit-mask:
    linear-gradient(#000 0 0) top left, linear-gradient(#000 0 0) top right,
    linear-gradient(#000 0 0) bottom left, linear-gradient(#000 0 0) bottom right;
  -webkit-mask-size: 18px 18px; -webkit-mask-repeat: no-repeat;
  mask:
    linear-gradient(#000 0 0) top left, linear-gradient(#000 0 0) top right,
    linear-gradient(#000 0 0) bottom left, linear-gradient(#000 0 0) bottom right;
  mask-size: 18px 18px; mask-repeat: no-repeat;
}
.section-card:hover::before, .profile-card:hover::before { opacity: 1; inset: 6px; }

.section-card::after, .profile-card::after { display: none; }

.section-plain { padding: 4px 0 8px; }

.section-head {
  display: flex; align-items: baseline; gap: 12px;
  margin-bottom: 22px;
  padding-bottom: 14px;
  border-bottom: 1px solid var(--rule);
}
.section-head h2 {
  font-family: var(--serif);
  font-size: 1.55rem; font-weight: 600; letter-spacing: -0.02em; margin: 0;
}
/* About */
.hello-heading {
  font-family: var(--serif);
  font-size: 2.2rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin: 0 0 10px;
  color: var(--ink);
}
.lead { font-size: 1.1rem; color: var(--ink2); margin: 0 0 12px; }
.intro { font-size: 1rem; color: var(--ink2); margin: 0 0 12px; line-height: 1.75; }
.intro:last-child { margin-bottom: 0; }
.intro strong, .lead strong { color: var(--ink2); font-weight: 600; }
.intro a, .lead a {
  color: var(--accent);
  border-bottom: 1px solid rgba(194,104,63,0.35);
  transition: border-color 0.18s ease;
}
.intro a:hover, .lead a:hover { border-color: var(--accent); }
.intro a strong, .lead a strong { color: inherit; }

/* Items */
.items { display: grid; gap: 4px; }

.item { padding: 16px 0; border-bottom: 1px solid rgba(0,0,0,0.07); }
.item:last-child { border-bottom: none; }
.item-head {
  display: flex; justify-content: space-between; align-items: baseline;
  gap: 12px; flex-wrap: wrap; margin-bottom: 4px;
}
.item-title { font-size: 1.05rem; font-weight: 600; letter-spacing: -0.01em; line-height: 1.4; }
.item-date {
  font-family: var(--mono);
  font-size: 0.85rem; color: var(--muted); white-space: nowrap;
}
.item-sub {
  font-family: var(--serif);
  font-style: italic;
  font-size: 1.02rem; color: var(--ink2); margin-bottom: 8px;
}
.item-body { font-size: 0.97rem; color: var(--ink2); margin: 0; line-height: 1.7; }

.edu-degree { font-size: 0.86rem; font-weight: 600; color: var(--ink); margin: 0 0 4px; }
.edu-advisor { font-size: 0.9rem; color: var(--muted); margin: 0; }
ul.item-body { padding-left: 17px; margin: 0; }
ul.item-body li { margin-bottom: 3px; }

.badge {
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.58rem; padding: 2px 7px; border-radius: 999px;
  background: rgba(0,0,0,0.08); color: var(--ink2);
  text-transform: uppercase; letter-spacing: 0.06em;
  vertical-align: middle; margin-left: 7px;
}
.badge.badge-ongoing { background: rgba(91,122,91,0.16); color: #4a684a; }
.badge.badge-course  { background: rgba(194,104,63,0.15); color: #a8552f; }

.pub-me { font-weight: 700; }

.pub-year {
  font-family: var(--serif);
  font-weight: 700; font-size: 1.3rem;
  margin: 24px 0 10px;
}
.pub-year:first-of-type { margin-top: 0; }

.pub-title { font-size: 1.05rem; font-weight: 600; color: var(--accent-2); line-height: 1.4; margin-bottom: 3px; }
.pub-authors { font-size: 0.92rem; color: var(--ink2); margin-bottom: 2px; }
.pub-venue { color: var(--muted); font-size: 0.88rem; font-style: italic; }

.pub-links { margin-top: 6px; display: flex; flex-wrap: wrap; align-items: center; gap: 8px; font-size: 0.85rem; }
.pub-links a { color: var(--accent); text-decoration: underline; text-decoration-color: rgba(194,104,63,0.4); text-underline-offset: 2px; }
.pub-links a:hover { text-decoration-color: var(--accent); }
.pub-links-sep { color: var(--soft); }
.pub-status { color: var(--muted); font-style: italic; }
.pub-link {
  display: inline-block;
  font-size: 0.75rem; padding: 3px 10px; border-radius: 999px;
  background: rgba(0,0,0,0.06); color: var(--ink2);
  border: 1px solid rgba(0,0,0,0.08);
  text-decoration: none;
  transition: background 0.18s ease, color 0.18s ease, border-color 0.18s ease;
}
.pub-link:hover { background: rgba(194,104,63,0.14); color: var(--accent); border-color: rgba(194,104,63,0.35); }

.pub-item { display: flex; gap: 20px; align-items: flex-start; }
.pub-thumb {
  width: 220px; flex-shrink: 0; border-radius: 10px;
  aspect-ratio: 16 / 9; object-fit: cover;
  border: 1px solid rgba(0,0,0,0.08);
}
.pub-thumb-pending {
  display: flex; align-items: center; justify-content: center;
  background: rgba(0,0,0,0.03);
  font-size: 2rem; color: var(--soft);
}
.pub-item-content { min-width: 0; }
@media (max-width: 640px) {
  .pub-item { flex-direction: column; }
  .pub-thumb { width: 100%; }
}

.empty-note { color: var(--muted); font-size: 0.9rem; margin: 4px 0 0; }

.group-label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--mono);
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--soft);
  margin: 22px 0 8px;
}
.group-label::before {
  content: "";
  width: 8px; height: 8px; border-radius: 999px;
  background: currentColor;
}
.group-label.research { color: var(--accent-2); }
.group-label.course   { color: var(--accent); }
.group-label:first-of-type { margin-top: 0; }
.item-body a {
  color: var(--accent);
  border-bottom: 1px solid rgba(194,104,63,0.35);
  transition: border-color 0.18s ease;
}
.item-body a:hover { border-color: var(--accent); }

/* ── Research journey (3D) ── */
.journey-section { margin-top: 28px; }
.journey-card {
  background: #14141a;
  border-radius: 22px;
  padding: 28px;
}
.journey-chapters {
  display: flex; flex-wrap: wrap; gap: 8px 24px;
  margin-bottom: 16px;
}
.journey-chapter {
  color: #9a9aa6;
  font-size: 0.85rem;
  line-height: 1.5;
  flex: 1 1 260px;
}
.journey-chapter strong { color: #e2e2e8; font-family: var(--serif); }
@media (max-width: 640px) {
  .journey-chapters { flex-direction: column; }
  .journey-chapter { flex-basis: auto; }
}
.journey-scene {
  position: relative;
  width: 100%; height: 420px;
  border-radius: 16px;
  overflow: hidden;
  background: radial-gradient(circle at 50% 40%, #1c1c24 0%, #0e0e12 100%);
}
.journey-scene canvas { display: block; width: 100%; height: 100%; }
.journey-tag {
  position: absolute;
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  color: #d6d6de;
  pointer-events: none;
}
.journey-tag-merge {
  bottom: 18px; left: 50%; transform: translateX(-50%);
  color: #8f8f9c; font-style: italic;
}
.journey-punch {
  color: var(--accent);
  font-weight: 600;
  font-size: 1.05rem;
  text-align: center;
  margin: 18px 0 0;
}

@media (max-width: 920px) {
  .journey-scene { height: 300px; }
}
@media (max-width: 640px) {
  .journey-scene { height: 240px; }
  .journey-tag { font-size: 0.64rem; }
}

/* ── Life (gallery, breaks the card mold) ── */
.life-heading {
  font-family: var(--serif);
  font-size: 1.9rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin: 0 0 22px;
}
.life-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 22px;
}
.life-tile {
  display: block;
  transition: transform 0.2s ease;
}
.life-tile:hover { transform: translateY(-4px); }
.life-tile img {
  width: 100%; aspect-ratio: 16 / 9; object-fit: cover;
  border-radius: 14px;
  box-shadow: 0 6px 20px rgba(0,0,0,0.12);
}
.life-caption {
  display: block;
  margin-top: 10px;
  font-weight: 600;
  font-size: 0.95rem;
  color: var(--ink);
}
.life-tile:hover .life-caption { color: var(--accent); }

/* ── Footer ── */
.footer {
  width: min(var(--wrap), calc(100% - 44px));
  margin: 8px auto 0;
  padding: 22px 0 30px;
  display: flex; justify-content: space-between; align-items: center;
  border-top: 1px solid var(--rule);
  flex-wrap: wrap; gap: 8px;
}
.footer-copy { font-family: var(--mono); font-size: 0.66rem; color: var(--soft); }

/* ── Entrance animation ── */
.fade-up { opacity: 0; transform: translateY(14px); animation: fadeUp 0.6s var(--ease) forwards; }
.content .section:nth-child(1) .fade-up,
.content .section:nth-child(1) { animation-delay: 0.04s; }
@keyframes fadeUp { to { opacity: 1; transform: translateY(0); } }

/* Copy-to-clipboard email feedback */
.copy-email.copied .c-label::after {
  content: " · copied ✓"; color: #2f9e6f; font-size: 0.78em;
}
.toast {
  position: fixed; bottom: 26px; left: 50%;
  transform: translate(-50%, 16px);
  padding: 9px 16px; border-radius: 999px;
  background: rgba(20,20,24,0.9); color: #fff;
  font-size: 0.82rem; z-index: 200;
  opacity: 0; pointer-events: none;
  transition: opacity 0.28s ease, transform 0.28s var(--ease);
  box-shadow: 0 10px 30px rgba(0,0,0,0.3);
}
.toast.show { opacity: 1; transform: translate(-50%, 0); }

/* ── Responsive ── */
@media (max-width: 920px) {
  .layout { grid-template-columns: 1fr; gap: 28px; }
  .sidebar { position: static; }
  .profile-card { display: grid; grid-template-columns: 200px 1fr; gap: 24px; align-items: start; }
  .profile-image { margin: 0; }
  .profile-card .divider:first-of-type { display: none; }
}

@media (max-width: 640px) {
  .page { width: calc(100% - 28px); }
  .section-card { padding: 24px 22px; }
  .profile-card { grid-template-columns: 1fr; gap: 18px; }
  .profile-image { max-width: 160px; }
  .top-nav-inner { width: calc(100% - 28px); gap: 12px; }
  .top-nav-brand { display: none; }
  .pub-thumb { width: 100%; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}