/*
  Site stylesheet — clean academic style.
  - Restrained palette, generous whitespace
  - Serif display headings + sans-serif body
  - Single source of truth for spacing/colors via CSS variables
*/

:root {
  --bg:        #ffffff;
  --surface:   #f7f8fa;   /* subtle section / card background */
  --text:      #1f2430;   /* primary text */
  --muted:     #5c6470;   /* secondary text */
  --border:    #e6e8ec;   /* hairline borders */
  --accent:    #1d4ed8;   /* link / accent (calm blue) */
  --accent-ink:#0f172a;   /* heading ink */

  --font-serif: Georgia, "Times New Roman", "Songti SC", serif;
  --font-sans:  -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
                "Helvetica Neue", Arial, "PingFang SC", sans-serif;

  --container: 1040px;
  --radius: 10px;
}

/* ---------- Base ---------- */
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

h1, h2, h3 { font-family: var(--font-serif); color: var(--accent-ink); line-height: 1.25; }
h2 {
  font-size: 1.6rem;
  margin: 2.5rem 0 1rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--border);
}
h3 { font-size: 1.2rem; margin: 1.75rem 0 0.5rem; }
p  { margin: 0 0 1rem; }

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

img { max-width: 100%; height: auto; }

.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 1.25rem; }

/* ---------- Header / nav ---------- */
.site-header {
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}
.site-header nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
  padding: 0.85rem 1.25rem;
}
.site-title { font-family: var(--font-serif); font-size: 1.15rem; font-weight: 600; margin: 0; }
.site-title a { color: var(--accent-ink); }
.site-title a:hover { text-decoration: none; }

nav ul { list-style: none; margin: 0; padding: 0; display: flex; gap: 0.25rem; flex-wrap: wrap; }
nav ul a {
  color: var(--muted);
  font-size: 0.95rem;
  padding: 0.4rem 0.7rem;
  border-radius: 6px;
}
nav ul a:hover { color: var(--accent-ink); background: var(--surface); text-decoration: none; }
nav ul a.active { color: var(--accent-ink); background: var(--surface); }

/* ---------- Main ---------- */
main.container { margin-top: 2.5rem; margin-bottom: 3.5rem; flex: 1 0 auto; }

/* ---------- Hero (intro) ---------- */
.intro {
  display: flex;
  align-items: center;
  gap: 2rem;
  margin-bottom: 1rem;
}
.intro__photo {
  flex: 0 0 auto;
  width: 170px;
  height: 170px;
  border-radius: 50%;
  object-fit: cover;
  border: 1px solid var(--border);
}
.intro__body { flex: 1 1 auto; min-width: 0; }
.intro__body h1 { font-size: 2.1rem; margin: 0 0 0.25rem; }
.intro__role { color: var(--muted); font-size: 1.05rem; margin: 0 0 0.75rem; }
.intro__lead { margin: 0 0 1rem; }

/* inline link row (email / CV / github) */
.links { display: flex; flex-wrap: wrap; gap: 0.5rem 0.75rem; align-items: center; }
.links a {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  font-size: 0.95rem;
  padding: 0.35rem 0.8rem;
  border: 1px solid var(--border);
  border-radius: 999px;
  color: var(--text);
}
.links a:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block;
  padding: 0.5rem 1.1rem;
  background: var(--accent);
  color: #fff;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.95rem;
}
.btn:hover { background: #1740b8; text-decoration: none; }

/* ---------- Cards / info lists ---------- */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 1rem 1.25rem;
  border-radius: var(--radius);
  margin-bottom: 1rem;
}
.card ul { margin: 0; padding-left: 1.1rem; }
.card li { margin: 0.3rem 0; }
.card > :first-child { margin-top: 0; }
.card > :last-child { margin-bottom: 0; }
.card h3 { margin-top: 0; }

.section-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

/* ---------- News ---------- */
.news { list-style: none; margin: 0; padding: 0; }
.news li {
  display: flex;
  gap: 1rem;
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--border);
}
.news li:first-child { padding-top: 0; }
.news li:last-child { padding-bottom: 0; border-bottom: 0; }
.news__date {
  flex: 0 0 8rem;
  color: var(--accent);
  font-weight: 600;
  font-size: 0.9rem;
  white-space: nowrap;
}
@media (max-width: 560px) {
  .news li { flex-direction: column; gap: 0.15rem; }
  .news__date { flex-basis: auto; }
}

/* ---------- Skill tags ---------- */
.skills { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.tag {
  display: inline-block;
  padding: 0.35rem 0.8rem;
  font-size: 0.9rem;
  line-height: 1.3;
  color: var(--text);
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 999px;
  transition: border-color 0.15s ease, color 0.15s ease;
}
.tag:hover { border-color: var(--accent); color: var(--accent); }
.tag--primary { background: rgba(29, 78, 216, 0.08); border-color: rgba(29, 78, 216, 0.25); color: var(--accent-ink); }
.tag small { color: var(--muted); font-size: 0.78em; }

/* ---------- Figures (image pairs) ---------- */
.figure-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.25rem;
  margin: 1.25rem 0;
}
figure { margin: 0; }
figure img { width: 100%; border-radius: var(--radius); border: 1px solid var(--border); display: block; }
figcaption { margin-top: 0.5rem; font-size: 0.85rem; color: var(--muted); text-align: center; }

/* feature images on home page */
.features { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1.25rem; margin: 1.5rem 0; }
.feature-img { width: 100%; border-radius: var(--radius); border: 1px solid var(--border); object-fit: cover; }

/* ---------- Carousel (home) ---------- */
.carousel { position: relative; margin: 1.5rem 0; overflow: hidden; }
.carousel__track {
  display: flex;
  gap: 1rem;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  padding-bottom: 0.25rem;
  scrollbar-width: none;          /* hide scrollbar for clean marquee */
}
.carousel__track::-webkit-scrollbar { display: none; }
.carousel__item {
  flex: 0 0 auto;
  width: clamp(260px, 46%, 440px);
  margin: 0;
}
.carousel__item img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  display: block;
}
.carousel__item figcaption {
  margin-top: 0.45rem;
  font-size: 0.85rem;
  color: var(--muted);
  text-align: center;
  line-height: 1.4;
}
.carousel__btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  z-index: 2;
  width: 2.6rem;
  height: 2.6rem;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.92);
  color: var(--accent-ink);
  font-size: 1.5rem;
  line-height: 1;
  cursor: pointer;
  box-shadow: 0 2px 10px rgba(15, 23, 42, 0.12);
  display: flex;
  align-items: center;
  justify-content: center;
}
.carousel__btn:hover { background: #fff; border-color: var(--accent); color: var(--accent); }
.carousel__btn--prev { left: 0.5rem; }
.carousel__btn--next { right: 0.5rem; }
.carousel__btn[hidden] { display: none; }

hr.divider { border: 0; height: 1px; background: var(--border); margin: 2.5rem 0; }

/* ---------- Publications ---------- */
.pub-list { list-style: none; margin: 0; padding: 0; counter-reset: pub; }
.pub-list li {
  position: relative;
  padding: 0 0 1.25rem 2.25rem;
  margin-bottom: 1.25rem;
  border-bottom: 1px solid var(--border);
}
.pub-list li:last-child { border-bottom: 0; margin-bottom: 0; }
.pub-list li::before {
  counter-increment: pub;
  content: counter(pub);
  position: absolute;
  left: 0;
  top: 0;
  width: 1.6rem;
  height: 1.6rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 50%;
  text-align: center;
  line-height: 1.6rem;
  font-size: 0.85rem;
  color: var(--muted);
}

/* ---------- Projects listing ---------- */
.project-list { display: grid; gap: 1.25rem; margin: 1.5rem 0; }
.project-card {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 1.25rem;
  align-items: center;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1rem;
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s ease, transform 0.15s ease;
}
.project-card:hover { border-color: var(--accent); transform: translateY(-2px); text-decoration: none; }
.project-card img { width: 100%; height: 140px; object-fit: contain; background: #fff; border-radius: 8px; border: 1px solid var(--border); }
.project-card h3 { margin: 0 0 0.35rem; }
.project-card .venue { color: var(--muted); font-size: 0.9rem; margin: 0 0 0.4rem; }
.project-card p { margin: 0; color: var(--text); }
@media (max-width: 600px) {
  .project-card { grid-template-columns: 1fr; }
  .project-card img { height: 200px; }
}

/* ---------- Project page ---------- */
.project-hero { text-align: center; margin: 0.5rem 0 2rem; }
.project-hero h1 { font-size: 2rem; line-height: 1.3; margin: 0 0 0.75rem; }
.project-hero .authors { color: var(--text); margin: 0 0 0.25rem; line-height: 1.6; }
.project-hero .affil { color: var(--muted); font-size: 0.9rem; margin: 0 0 0.5rem; }
.project-hero .venue { color: var(--muted); font-style: italic; margin: 0 0 1.25rem; }
sup { font-size: 0.7em; }

/* Tables (e.g. results) */
table { width: 100%; border-collapse: collapse; margin: 1.25rem 0; font-size: 0.95rem; }
th, td { text-align: left; padding: 0.5rem 0.7rem; border-bottom: 1px solid var(--border); }
thead th { color: var(--accent-ink); border-bottom: 2px solid var(--border); }
tbody tr:last-child td { border-bottom: 2px solid var(--border); }
table strong { color: var(--accent-ink); }
.project-hero .links { justify-content: center; }
.link--pending { color: var(--muted) !important; border-style: dashed !important; cursor: default; }
.link--pending:hover { border-color: var(--border) !important; color: var(--muted) !important; }

.video-wrap {
  width: 100%;
  margin: 1.5rem 0;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  background: #000;
  aspect-ratio: 16 / 9;
}
.video-wrap iframe,
.video-wrap video { display: block; width: 100%; height: 100%; border: 0; object-fit: contain; }

.bibtex {
  background: #0f172a;
  color: #e2e8f0;
  padding: 1rem 1.25rem;
  border-radius: var(--radius);
  overflow-x: auto;
  font-size: 0.85rem;
  line-height: 1.5;
}
.bibtex code { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; }

/* ---------- Lightbox ---------- */
img.zoomable { cursor: zoom-in; transition: filter 0.15s ease; }
img.zoomable:hover { filter: brightness(0.93); }

.lightbox {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: none;
  align-items: center;
  justify-content: center;
  padding: 2rem;
  background: rgba(15, 23, 42, 0.9);
}
.lightbox.is-open { display: flex; }
.lightbox__img {
  max-width: 95vw;
  max-height: 90vh;
  border-radius: var(--radius);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.5);
  cursor: default;
}
.lightbox__close {
  position: absolute;
  top: 0.75rem;
  right: 1.25rem;
  width: 2.5rem;
  height: 2.5rem;
  font-size: 2rem;
  line-height: 1;
  color: #fff;
  background: transparent;
  border: 0;
  cursor: pointer;
  opacity: 0.8;
}
.lightbox__close:hover { opacity: 1; }

/* ---------- Footer ---------- */
.site-footer {
  margin-top: auto;
  border-top: 1px solid var(--border);
  background: var(--surface);
  color: var(--muted);
  font-size: 0.9rem;
  padding: 1.5rem 0;
  text-align: center;
}
.site-footer a { color: var(--muted); }

/* ---------- Responsive ---------- */
@media (max-width: 680px) {
  .intro { flex-direction: column; text-align: center; gap: 1.25rem; }
  .links { justify-content: center; }
  .figure-grid, .features { grid-template-columns: 1fr; }
  .intro__body h1 { font-size: 1.8rem; }
}