/* ===== Theme Variables (simple) ===== */
/* Light: white + warm yellow accent (Seulgi-ish) */
/* Dark: dark blue + cool blue accent (Wendy-ish) */

:root {
  --bg: #e4e4e0;
  --bg-alt: #f3f3f2;
  --accent: #f5b620;
  --accent-soft: #fef3c7;
  --text: #111827;
  --text-muted: #4a4e57;
  --border: #e5e7eb;
  --radius-lg: 12px;
  --radius-pill: 999px;
}

/* Dark theme overrides */
html[data-theme="dark"] {
  --bg: #0c0e20;
  --bg-alt: #020617;
  --accent: #ab3bf6;
  --accent-soft: #b855f9;
  --text: #e5e7eb;
  --text-muted: #9ca3af;
  --border: #1f2937;
}
/* Dark theme for the icons */
html[data-theme="dark"] .contact-icon.github   { content: url("assets/icons/github-dark.svg"); }
html[data-theme="dark"] .contact-icon.linkedin { content: url("assets/icons/linkedin-dark.svg"); }
html[data-theme="dark"] .contact-icon.gscholar  { content: url("assets/icons/gscholar-dark.svg"); }

html.theme-transition * {
  transition:
    background-color 0.25s ease,
    color 0.25s ease,
    border-color 0.25s ease,
    box-shadow 0.25s ease;
}

/* ===== Global ===== */

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

html,
body {
  scroll-behavior: smooth;
  font-family: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
}

body {
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
}

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



/* ===== Header / Nav ===== */

header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--bg-alt);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: 900px;
  margin: 0 auto;
  padding: 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.brand-logo {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  border: 2px solid var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.95rem;
}

.brand-title {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
  font-size: 0.85rem;
}

.brand-title span:last-child {
  color: var(--text-muted);
  font-size: 0.75rem;
}

.brand-title span:first-child {
  font-weight: 600;
}

/* Nav */

.nav-right {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

nav {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  font-size: 0.82rem;
}

.nav-link {
  padding: 0.3rem 0.8rem;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
}

.nav-link:hover {
  color: var(--text);
  border-color: var(--border);
}

.nav-link.active {
  color: var(--text);
  background: var(--accent-soft);
  border-color: var(--accent);
}

/* Theme toggle + mobile toggle */

.theme-toggle,
.nav-toggle {
  border-radius: var(--radius-pill);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 0.3rem 0.7rem;
  font-size: 0.8rem;
  background: var(--bg-alt);
  cursor: pointer;
}

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.nav-toggle {
  display: none;
}

/* ===== Layout ===== */

main {
  max-width: 900px;
  margin: 0 auto;
  padding: 2rem 1.25rem 2.5rem;
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

section {
  scroll-margin-top: 80px;
}

.section-card {
  background: var(--bg-alt);
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
  padding: 1.5rem 1.5rem 1.6rem;
}

.section-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.section-title {
  font-size: 1rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent);
}

.section-subtitle {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.pill {
  font-size: 0.72rem;
  border-radius: var(--radius-pill);
  padding: 0.1rem 0.6rem;
  border: 1px solid var(--border);
  color: var(--text-muted);
}

/* ===== Intro ===== */

.intro-layout {
  display: grid;
  grid-template-columns: minmax(0, 2fr) minmax(0, 1.2fr);
  gap: 1.5rem;
  align-items: center;
}

.intro-heading {
  font-size: 1.8rem;
  font-weight: 450;
  margin-bottom: 0.7rem;
}

.intro-highlight {
  display: inline-flex;
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border);
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 0.6rem;
}

.intro-text {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin-bottom: 0.9rem;
}

.intro-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
  font-size: 0.75rem;
}

.tag {
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border);
}

/* Simple avatar */

.intro-right {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.4rem;
}

.avatar-wrapper {
  position: relative;
  display: block;   /* so tooltip width is based on avatar */
  width: 100%;
}

/* your existing avatar is fine, keep this */
.avatar-simple {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  margin: 0 auto;
}

.avatar-photo {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
  display: block;
}

/* tooltip box */
.avatar-tooltip {
  position: absolute;
  top: calc(100% + 10px);   /* below the avatar; use bottom: calc(100% + 10px) for above */
  left: 50%;
  transform: translateX(-50%);
  background: var(--bg-alt);
  color: var(--text);
  padding: 8px 12px;
  font-size: 0.78rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  max-width: 980px;
  text-align: center;
  white-space: normal;
  line-height: 1.35;
  box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);

  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease, transform 0.25s ease;
}

/* show on hover */
.avatar-simple:hover + .avatar-tooltip {
  opacity: 1;
  transform: translateX(-50%) translateY(2px); /* slight slide in */
}

/* tooltip dark mode */
html[data-theme="dark"] .avatar-tooltip {
  background: #111827;
  color: #f9fafb;
  border-color: #374151;
}

.avatar-photo {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;     /* keeps aspect ratio, fills the circle */
  display: block;
}

.avatar-label {
  font-size: 0.78rem;
  color: var(--text-muted);
}

/* ===== Education (Timeline) ===== */

.timeline {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.timeline-item {
  padding: 0.8rem 0.9rem;
  border-radius: 8px;
  border: 1.0px solid var(--border);
  display: grid;
  grid-template-columns: minmax(0, 2fr) minmax(0, 1fr);
  column-gap: 0.8rem;
  row-gap: 0.25rem;
  font-size: 0.88rem;
}

.timeline-main {
  font-weight: 500;
}

.timeline-university {
  color: var(--text-muted);
}
.timeline-university a:hover {
  text-decoration: underline;
  cursor: pointer;
}


.timeline-meta {
  text-align: right;
  font-size: 0.78rem;
  color: var(--text-muted);
}

.timeline-sub {
  grid-column: 1 / -1;
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ===== Publications ===== */

.pub-list {
  display: flex;
  flex-direction: column;
  font-size: 0.86rem;
}

.pub-item + .pub-item {
    margin-top: 0.4rem;
}

.pub-item {
  border-radius: 8px;
  border: 1.0px solid var(--border);
  padding: 0.75rem 0.9rem;
}

.pub-author {
  font-weight: 200;
  margin-bottom: 0.25rem;
  font-size: 0.75rem;
}

.pub-title {
  font-weight: 500;
  margin-bottom: 0.25rem;
  font-style: italic;
}

.pub-venue {
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 0.25rem;
}

.pub-venue .pub-best-paper {
  font-size: 0.78rem;
  color: var(--text);
  background-color: var(--accent);
  margin-bottom: 0.25rem;
  padding: 0% 1.5rem;
}

.pub-link {
  font-size: 0.8rem;
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* Hidden state (collapsed) */
#pub-list .pub-item--extra {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  transform: translateY(-8px);
  border: 1.0px solid var(--border);
  margin-top: 0;
  padding-top: 0;
  padding-bottom: 0;
  border-width: 0;
  transition:
    max-height 0.35s ease,
    opacity 0.25s ease,
    transform 0.25s ease,
    margin-top 0.25s ease,
    padding 0.25s ease,
    border-width 0.25s ease,
    border 0.05s ease;
}

/* Visible state (expanded) */
#pub-list.is-expanded .pub-item--extra {
  max-height: 400px;           /* just needs to be > actual item height */
  opacity: 1;
  transform: translateY(0);
  margin-top: 0.4rem;        /* nice gap between items */
  padding-top: 0.75rem;
  padding-bottom: 0.75rem;
  border: 1.0px solid var(--border);
}

/* Optional: basic styling for the toggle button */
.pub-toggle-btn {
  margin-bottom: 1rem;
  border: none;
  border-radius: 999px;
  padding: 0.4rem 0.9rem;
  cursor: pointer;
}

#pubToggleBtn {
  padding: 0.45rem 1rem;
  border-radius: 999px;
  border: none;
  cursor: pointer;
  font-size: 0.85rem;
  text-transform: none;      /* prevents ALL CAPS */
  transition: background 0.25s ease, color 0.25s ease;
}

/* Collapsed state (default) */
#pubToggleBtn:not(.expanded) {
  color: #111827;
  background: #f5b620;
}

/* Expanded state */
#pubToggleBtn.expanded {
  background: #111827;
  color: #f5b620;
}

html[data-theme="dark"] #pubToggleBtn:not(.expanded) {
  background: #b855f9;
  color: #eee;
}

/* Expanded state */
html[data-theme="dark"] #pubToggleBtn.expanded {
  background: #eee;
  color: #b855f9;
}

/* ===== News ===== */

.news-list {
  display: flex;
  flex-direction: column;
  font-size: 0.80rem;
}

.news-item + .news-item {
    margin-top: 0.4rem;
}

.news-item {
  display: flex;
  align-items: baseline;
  gap: 0.80rem;
  border-radius: 8px;
  border: 1.0px solid var(--border);
  padding: 0.6rem 0.8rem;
}

.news-date {
  font-size: 0.80rem;
  color: var(--text-muted);
  min-width: 5.2rem;
  white-space: nowrap;
}

/* Hidden state (collapsed) */
#news-list .news-item--extra {
  max-height: 0;
  overflow: hidden;
  opacity: 0;
  transform: translateY(-8px);
  border: 1.3px solid var(--border);
  margin-top: 0;
  padding-top: 0;
  padding-bottom: 0;
  border-width: 0;
  transition:
    max-height 0.35s ease,
    opacity 0.25s ease,
    transform 0.25s ease,
    margin-top 0.25s ease,
    padding 0.25s ease,
    border-width 0.25s ease,
    border 0.05s ease;
}

/* Visible state (expanded) */
#news-list.is-expanded .news-item--extra {
  max-height: 400px;           /* just needs to be > actual item height */
  opacity: 1;
  transform: translateY(0);
  margin-top: 0.4rem;        /* nice gap between items */
  padding-top: 0.75rem;
  padding-bottom: 0.75rem;
  border: 1.0px solid var(--border);
}

/* Optional: basic styling for the toggle button */
.news-toggle-btn {
  margin-bottom: 1rem;
  border: none;
  border-radius: 999px;
  padding: 0.4rem 0.9rem;
  cursor: pointer;
}

#newsToggleBtn {
  padding: 0.45rem 1rem;
  border-radius: 999px;
  border: none;
  cursor: pointer;
  font-size: 0.85rem;
  text-transform: none;      /* prevents ALL CAPS */
  transition: background 0.25s ease, color 0.25s ease;
}

/* Collapsed state (default) */
#newsToggleBtn:not(.expanded) {
  color: #111827;
  background: #f5b620;
}

/* Expanded state */
#newsToggleBtn.expanded {
  background: #111827;
  color: #f5b620;
}

html[data-theme="dark"] #newsToggleBtn:not(.expanded) {
  background: #b855f9;
  color: #eee;
}

/* Expanded state */
html[data-theme="dark"] #newsToggleBtn.expanded {
  background: #eee;
  color: #b855f9;
}

/* ===== Contact ===== */

.contact-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.3fr) minmax(0, 1.2fr);
  gap: 1.3rem;
  align-items: flex-start;
}

.contact-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  font-size: 0.88rem;
}

.contact-label {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--text-muted);
}

.contact-value {
  font-weight: 500;
}

.contact-email {
  color: var(--accent);
  text-decoration: underline;
}

.contact-chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-top: 0.4rem;
  font-size: 0.8rem;
}

.chip {
  padding: 0.22rem 0.7rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border);
}

.contact-icon {
  width: 28px;
  height: 28px;
  opacity: 0.74;
  transition: opacity .2s;
}
.contact-icon:hover {
  opacity: 1;
}

/* ===== Footer ===== */

footer {
  max-width: 900px;
  margin: 0 auto;
  padding: 0 1.25rem 2rem;
  font-size: 0.75rem;
  color: var(--text-muted);
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  border-top: 1px solid var(--border);
  padding-top: 0.9rem;
}

/* ===== Responsive ===== */

@media (max-width: 800px) {
  .intro-layout,
  .contact-grid {
    grid-template-columns: minmax(0, 1fr);
  }

  .intro-right {
    order: -1;
  }
}

@media (max-width: 680px) {
  .nav-toggle {
    display: inline-flex;
  }

  nav {
    position: absolute;
    inset: 100% 0 auto;
    padding: 0.4rem 1.25rem 0.8rem;
    background: var(--bg-alt);
    border-bottom: 1px solid var(--border);
    flex-wrap: wrap;
    gap: 0.25rem;
    opacity: 0;
    pointer-events: none;
    transform: translateY(-4px);
    transition: opacity 0.15s ease-out, transform 0.15s ease-out;
  }

  nav.open {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
    transition: opacity 0.15s ease-out, transform 0.15s ease-out;
  }

  main {
    padding-top: 1.5rem;
  }

  .section-card {
    padding: 1.3rem 1.1rem 1.4rem;
  }

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

@media (max-width: 480px) {
  .timeline-item {
    grid-template-columns: minmax(0, 1fr);
  }

  .timeline-meta {
    text-align: left;
  }
}