/* ============================================================
   Academic homepage — clean serif/sans hybrid, light & dark
   ============================================================ */

:root {
  --bg: #ffffff;
  --bg-subtle: #f6f7f9;
  --text: #1a1f27;
  --text-muted: #5b6472;
  --accent: #1d4ed8;
  --accent-hover: #1e40af;
  --border: #e3e6ea;
  --tag-bg: #eef2f8;
  --max-width: 760px;
}

html[data-theme="dark"] {
  --bg: #11141a;
  --bg-subtle: #1a1e26;
  --text: #e6e9ee;
  --text-muted: #9aa3b0;
  --accent: #7aa2ff;
  --accent-hover: #a3bdff;
  --border: #2a2f3a;
  --tag-bg: #222835;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: "Inter", -apple-system, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  transition: background 0.2s ease, color 0.2s ease;
}

h1, h2, h3 {
  font-family: "Source Serif 4", Georgia, "Songti SC", serif;
  line-height: 1.3;
}

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

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

/* ---------- Nav ---------- */
.nav {
  position: sticky;
  top: 0;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  z-index: 10;
  backdrop-filter: blur(8px);
}
.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0.75rem 1.25rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-brand {
  font-family: "Source Serif 4", Georgia, serif;
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--text);
}
.nav-brand:hover { text-decoration: none; color: var(--accent); }
.nav-links {
  display: flex;
  align-items: center;
  gap: 1.1rem;
}
.nav-links a {
  color: var(--text-muted);
  font-size: 0.92rem;
  font-weight: 500;
}
.nav-links a.active, .nav-links a:hover { color: var(--text); text-decoration: none; }

.theme-toggle {
  background: none;
  border: 1px solid var(--border);
  border-radius: 50%;
  width: 30px;
  height: 30px;
  cursor: pointer;
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1;
}
.theme-toggle:hover { color: var(--text); border-color: var(--text-muted); }

/* Small illustrated entrance to the flight experiment, at the far right. */
.nav-inner:has(.nav-roadster) { gap: 1.25rem; }
.nav-inner:has(.nav-roadster) .nav-links { margin-left: auto; }
.nav-roadster { display:flex; flex:none; flex-direction:column; align-items:center; justify-content:center; min-width:104px; min-height:48px; padding:3px 5px 5px; border:1px solid #30343a; border-radius:8px; background:#050608; color:#cbd2da; transition:border-color .2s, background .2s; }
.nav-roadster img { display:block; width:96px; height:35px; object-fit:contain; transition:transform .2s; }
.nav-roadster span { font:600 8px/1.2 Inter,sans-serif; letter-spacing:.16em; }
.nav-roadster:hover { text-decoration:none; color:#fff; background:#101318; border-color:#697481; }
.nav-roadster:hover img { transform:translateX(-3px); }
.nav-roadster:focus-visible { outline:2px solid var(--accent); outline-offset:4px; }
@media(prefers-reduced-motion:reduce) { .nav-roadster, .nav-roadster img { transition:none; } .nav-roadster:hover img { transform:none; } }

/* ---------- Hero ---------- */
.hero {
  display: flex;
  gap: 2.5rem;
  align-items: flex-start;
  padding: 3rem 0 1rem;
}
.hero-text { flex: 1; }
.hero h1 {
  margin: 0 0 0.25rem;
  font-size: 2.1rem;
}
.hero-title {
  margin: 0 0 1rem;
  color: var(--text-muted);
  font-weight: 500;
}
.hero-bio { margin: 0 0 1.25rem; }
.hero-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.25rem;
  font-weight: 500;
  font-size: 0.95rem;
}
.hero-photo img {
  width: 170px;
  height: 170px;
  object-fit: cover;
  border-radius: 12px;
  border: 1px solid var(--border);
}

/* ---------- Sections ---------- */
section { padding: 1.5rem 0; }
section h2 {
  font-size: 1.35rem;
  margin: 0 0 1rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--border);
}

/* ---------- News ---------- */
.news-list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.news-list li {
  display: flex;
  gap: 1rem;
  padding: 0.3rem 0;
}
.news-date {
  flex: 0 0 5.2rem;
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  padding-top: 0.1rem;
}

/* Dateless lists (news/activities without timestamps) */
.plain-list {
  list-style: none;
  margin: 0;
  padding: 0;
}
.plain-list li {
  padding: 0.3rem 0 0.3rem 1.1rem;
  position: relative;
}
.plain-list li::before {
  content: "‣";
  position: absolute;
  left: 0;
  color: var(--accent);
}

/* ---------- Tags ---------- */
.tags { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.tag {
  background: var(--tag-bg);
  border-radius: 999px;
  padding: 0.25rem 0.85rem;
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--text);
}

/* ---------- Publications ---------- */
.pub-group {
  font-size: 1.05rem;
  margin: 1.5rem 0 0.25rem;
  color: var(--text-muted);
}

.pub-list {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: pub;
}
.pub {
  padding: 0.9rem 0;
  border-bottom: 1px dashed var(--border);
}
.pub:last-child { border-bottom: none; }
.pub-title {
  font-weight: 600;
  font-size: 1.02rem;
}
.pub-authors { font-size: 0.93rem; margin-top: 0.15rem; }
.pub-venue {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-style: italic;
  margin-top: 0.1rem;
}
.pub-links {
  margin-top: 0.3rem;
  display: flex;
  gap: 0.9rem;
  font-size: 0.88rem;
  font-weight: 500;
}

.more-link { font-size: 0.92rem; margin-top: 0.75rem; }

.bib-btn {
  background: none;
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 0.1rem 0.6rem;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--accent);
  cursor: pointer;
  font-family: inherit;
  transition: border-color 0.15s ease, background 0.15s ease;
}
.bib-btn:hover { border-color: var(--accent); background: var(--tag-bg); }
.bib-btn.copied { color: #10b981; border-color: #10b981; }
.bib-src {
  width: 100%;
  margin-top: 0.5rem;
  font-family: ui-monospace, monospace;
  font-size: 0.78rem;
  background: var(--bg-subtle);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.6rem;
  min-height: 9em;
}

/* ---------- Blog cards (PaperMod style) ---------- */
.post-cards {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}
.post-card {
  position: relative;
  background: var(--bg-subtle);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.1rem 1.25rem;
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}
.post-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.08);
  border-color: var(--text-muted);
}
.post-card-title {
  font-family: "Source Serif 4", Georgia, serif;
  font-size: 1.25rem;
  font-weight: 700;
  margin: 0 0 0.4rem;
  line-height: 1.3;
  color: var(--text);
}
.post-card-excerpt {
  margin: 0 0 0.75rem;
  font-size: 0.93rem;
  color: var(--text-muted);
  line-height: 1.55;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.post-card-meta {
  font-size: 0.82rem;
  color: var(--text-muted);
}
.post-card-link {
  position: absolute;
  inset: 0;
  border-radius: 10px;
}

/* ---------- Blog list ---------- */
.post-list { display: flex; flex-direction: column; }
.post-item {
  display: flex;
  gap: 1.25rem;
  align-items: baseline;
  padding: 0.55rem 0;
  border-bottom: 1px dashed var(--border);
}
.post-item:last-child { border-bottom: none; }
.post-date {
  flex: 0 0 6.2rem;
  color: var(--text-muted);
  font-size: 0.88rem;
  font-variant-numeric: tabular-nums;
}
.post-title-link {
  font-weight: 500;
  font-size: 1rem;
}
.post-tags { margin-left: auto; display: flex; gap: 0.4rem; }
.post-tags .tag { font-size: 0.75rem; padding: 0.1rem 0.6rem; }

/* ---------- Blog article ---------- */
.article {
  padding: 2.5rem 0;
}
.article h1 {
  font-size: 1.9rem;
  margin: 0 0 0.4rem;
}
.article-meta {
  color: var(--text-muted);
  font-size: 0.92rem;
  margin-bottom: 2rem;
}
.article-body {
  font-size: 1.03rem;
}
.article-body h2 { border: none; padding: 0; margin-top: 2rem; }
.article-body pre {
  background: var(--bg-subtle);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1rem;
  overflow-x: auto;
  font-size: 0.88rem;
}
.article-body code {
  background: var(--bg-subtle);
  border-radius: 4px;
  padding: 0.1em 0.35em;
  font-size: 0.9em;
}
.article-body pre code { background: none; padding: 0; }
.article-body blockquote {
  margin: 1rem 0;
  padding: 0.2rem 1rem;
  border-left: 3px solid var(--accent);
  color: var(--text-muted);
  background: var(--bg-subtle);
  border-radius: 0 6px 6px 0;
}
.article-body img { max-width: 100%; border-radius: 8px; }

.back-link {
  display: inline-block;
  margin-bottom: 1.5rem;
  font-size: 0.92rem;
  font-weight: 500;
}

/* ---------- Placeholder highlight (remove class once filled in) ---------- */
.placeholder {
  background: linear-gradient(transparent 65%, rgba(255, 196, 0, 0.35) 65%);
  border-radius: 2px;
}
html[data-theme="dark"] .placeholder {
  background: linear-gradient(transparent 65%, rgba(255, 196, 0, 0.22) 65%);
}

/* ---------- Fun / interactivity ---------- */
.typing-line {
  color: var(--text-muted);
  font-size: 0.98rem;
  margin: -0.5rem 0 1rem;
  min-height: 1.5em;
}
#typed-interests { color: var(--accent); font-weight: 600; }
.typing-line .caret {
  display: inline-block;
  width: 2px;
  height: 1.05em;
  background: var(--accent);
  vertical-align: text-bottom;
  margin-left: 2px;
  animation: blink 1s steps(1) infinite;
}
@keyframes blink { 50% { opacity: 0; } }

.hero-photo img { transition: transform 0.25s ease, box-shadow 0.25s ease; }
.hero-photo img:hover { transform: scale(1.04) rotate(-1.5deg); box-shadow: 0 8px 28px rgba(0,0,0,0.18); }

.pub { transition: background 0.2s ease, padding-left 0.25s ease; border-radius: 6px; }
.pub:hover { background: var(--bg-subtle); padding-left: 0.6rem; }

.tag { transition: transform 0.15s ease, background 0.2s ease; }
.tag:hover { transform: translateY(-2px) scale(1.05); background: var(--accent); color: #fff; cursor: default; }

.post-item { transition: background 0.2s ease, padding-left 0.25s ease; border-radius: 6px; }
.post-item:hover { background: var(--bg-subtle); padding-left: 0.5rem; }

.confetti-canvas {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 999;
}

/* ---------- Footer ---------- */
.footer {
  border-top: 1px solid var(--border);
  margin-top: 3rem;
  padding: 1.5rem 1.25rem;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* ---------- Mobile ---------- */
@media (max-width: 640px) {
  .nav-inner:has(.nav-roadster) { flex-wrap:wrap; gap:.5rem 1rem; }
  .nav-inner:has(.nav-roadster) .nav-brand { flex:1; }
  .nav-inner:has(.nav-roadster) .nav-links { order:3; width:100%; margin:0; justify-content:space-between; gap:.5rem; }
  .nav-roadster { min-width:92px; }
  .nav-roadster img { width:84px; height:31px; }
  .hero {
    flex-direction: column-reverse;
    align-items: center;
    text-align: center;
    gap: 1.5rem;
    padding-top: 2rem;
  }
  .hero-links { justify-content: center; }
  .hero-photo img { width: 140px; height: 140px; border-radius: 50%; }
  .news-list li { flex-direction: column; gap: 0; }
  .post-item { flex-wrap: wrap; }
  .post-tags { display: none; }
}