/* ==========================================================
   Yunpeng Bai — personal homepage
   Cool, modern, minimal. One accent color, generous whitespace.
   ========================================================== */

:root {
  --bg: #fcfcfd;
  --bg-panel: #f2f4f7;
  --text: #1a1f2b;
  --text-muted: #5b6472;
  --text-faint: #8a93a2;
  --accent: #2456c9;
  --accent-soft: #e8eefb;
  --border: #e4e7ec;
  --thumb-bg: #eef0f4;
  --shadow: 0 1px 2px rgba(16, 24, 40, .04);
  --shadow-hover: 0 6px 20px rgba(16, 24, 40, .08);
}

[data-theme="dark"] {
  --bg: #0f1218;
  --bg-panel: #171c25;
  --text: #e6e9ef;
  --text-muted: #9aa4b2;
  --text-faint: #6c7684;
  --accent: #7da4f2;
  --accent-soft: #1b2740;
  --border: #262d39;
  --thumb-bg: #1b212c;
  --shadow: 0 1px 2px rgba(0, 0, 0, .3);
  --shadow-hover: 0 6px 20px rgba(0, 0, 0, .45);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Inter", "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 15.5px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  transition: background .25s ease, color .25s ease;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 32px 64px;
}

/* ---------- two-column layout ---------- */

.layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 72px;
  align-items: start;
}

.main-col { min-width: 0; }

.side-col {
  position: sticky;
  top: 32px;
  margin-top: 56px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: opacity .15s ease;
}

a:hover { opacity: .75; }

/* ---------- header ---------- */

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 28px 0 0;
}

.site-header .logo {
  font-size: 14px;
  font-weight: 600;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--text-faint);
  user-select: none;
}

.theme-toggle {
  border: 1px solid var(--border);
  background: var(--bg-panel);
  color: var(--text-muted);
  width: 36px;
  height: 36px;
  border-radius: 10px;
  cursor: pointer;
  font-size: 16px;
  line-height: 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: border-color .15s ease, transform .15s ease;
}

.theme-toggle:hover { border-color: var(--accent); transform: translateY(-1px); }

/* ---------- intro ---------- */

.intro {
  display: flex;
  gap: 48px;
  align-items: flex-start;
  margin-top: 56px;
}

.intro-text { flex: 1 1 auto; min-width: 0; }

.intro h1 {
  margin: 0;
  font-size: 34px;
  font-weight: 700;
  letter-spacing: -.02em;
  line-height: 1.2;
}

.intro h1 .cn {
  font-weight: 400;
  color: var(--text-muted);
  font-size: 24px;
  margin-left: 10px;
}

.intro .tagline {
  margin: 10px 0 0;
  color: var(--accent);
  font-size: 15px;
  font-weight: 500;
}

.hiring-banner {
  margin-top: 18px;
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 12px 16px;
  border-radius: 12px;
  background: #fdeceb;
  border-left: 3px solid #d64545;
  font-size: 14.5px;
  color: var(--text);
}

[data-theme="dark"] .hiring-banner {
  background: #3a1f1e;
  border-left-color: #e06c6c;
}

.hiring-banner b { font-weight: 650; }

.hiring-banner a { font-weight: 600; color: #c73e3e; }

[data-theme="dark"] .hiring-banner a { color: #f09a9a; }

.hiring-banner .dot {
  flex: none;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #d64545;
  margin-top: 7px;
  animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(214, 69, 69, .45); }
  50% { box-shadow: 0 0 0 5px rgba(214, 69, 69, 0); }
}

.intro .bio {
  margin-top: 20px;
  color: var(--text-muted);
}

.intro .bio a { font-weight: 500; }

.contact-row {
  margin-top: 22px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.contact-row a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border: 1px solid var(--border);
  border-radius: 999px;
  font-size: 13.5px;
  font-weight: 500;
  color: var(--text-muted);
  background: var(--bg-panel);
  transition: border-color .15s ease, color .15s ease;
}

.contact-row a:hover { border-color: var(--accent); color: var(--accent); opacity: 1; }

.portrait {
  flex: 0 0 190px;
}

.portrait img {
  width: 190px;
  height: 190px;
  object-fit: cover;
  border-radius: 18px;
  display: block;
  box-shadow: var(--shadow-hover);
}

/* ---------- section headings ---------- */

section { margin-top: 64px; }

.section-title {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin: 0 0 24px;
  font-size: 21px;
  font-weight: 700;
  letter-spacing: -.01em;
}

.section-title::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--border);
  align-self: center;
}

/* ---------- news ---------- */

.news-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.news-list li {
  display: flex;
  gap: 18px;
  padding: 7px 0;
  font-size: 14.5px;
}

.news-list .date {
  flex: 0 0 76px;
  color: var(--text-faint);
  font-variant-numeric: tabular-nums;
  font-size: 13.5px;
  padding-top: 1px;
}

.news-list .what { color: var(--text-muted); }

.news-list .what b { color: var(--text); font-weight: 600; }

.news-list .what a,
.news-list .what a b { color: var(--accent); }

.news-list .what a:hover { text-decoration: underline; opacity: 1; }

/* ---------- publications ---------- */

.pub {
  display: flex;
  gap: 24px;
  align-items: flex-start;
  padding: 22px 18px;
  margin: 0 -18px;
  border-radius: 16px;
  transition: background .15s ease, box-shadow .15s ease;
}

.pub:hover {
  background: var(--bg-panel);
  box-shadow: var(--shadow);
}

.pub-thumb {
  flex: 0 0 218px;
  aspect-ratio: 16 / 10;
  border-radius: 12px;
  background: var(--thumb-bg);
  border: 1px solid var(--border);
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
}

.pub-thumb img,
.pub-thumb video {
  width: 100%;
  height: 100%;
  object-fit: contain;   /* never crop the figure */
  display: block;
}

.pub-body { flex: 1 1 auto; min-width: 0; }

.pub-title {
  margin: 0;
  font-size: 16.5px;
  font-weight: 650;
  line-height: 1.45;
  letter-spacing: -.005em;
}

.pub-title a { color: var(--text); }
.pub-title a:hover { color: var(--accent); opacity: 1; }

.pub-authors {
  margin: 6px 0 0;
  font-size: 14px;
  color: var(--text-muted);
}

.pub-authors .me {
  font-weight: 650;
  color: var(--text);
}

.pub-venue {
  margin: 8px 0 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  font-size: 13px;
}

.venue-tag {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 6px;
  background: var(--accent-soft);
  color: var(--accent);
  font-weight: 600;
  letter-spacing: .01em;
}

.award-tag {
  display: inline-block;
  padding: 2px 10px;
  border-radius: 6px;
  background: rgba(217, 119, 6, .12);
  color: #c2740a;
  font-weight: 600;
}

[data-theme="dark"] .award-tag { color: #e8a33d; }

.pub-links {
  margin: 10px 0 0;
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  font-size: 13.5px;
  font-weight: 500;
}

.pub-abstract {
  margin: 10px 0 0;
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--text-faint);
}

.pub-abstract summary {
  cursor: pointer;
  color: var(--text-faint);
  user-select: none;
  list-style: none;
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

.pub-abstract summary::-webkit-details-marker { display: none; }

.pub-abstract summary::before {
  content: "›";
  display: inline-block;
  transition: transform .15s ease;
  font-size: 15px;
}

.pub-abstract[open] summary::before { transform: rotate(90deg); }

.pub-abstract summary:hover { color: var(--accent); }

.pub-abstract p { margin: 8px 0 0; }

/* ---------- sidebar ---------- */

.side-section { margin-top: 0; }

.side-section + .side-section { margin-top: 40px; }

.side-section .section-title { font-size: 17px; margin-bottom: 16px; }

.blog-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.blog-item {
  display: block;
  padding: 10px 12px;
  margin: 0 -12px;
  border-radius: 10px;
  transition: background .15s ease;
}

.blog-item:hover { background: var(--bg-panel); opacity: 1; }

.blog-date {
  display: block;
  font-size: 12px;
  color: var(--text-faint);
  font-variant-numeric: tabular-nums;
}

.blog-title {
  display: block;
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  line-height: 1.45;
}

.blog-item:hover .blog-title { color: var(--accent); }

.blog-excerpt {
  display: block;
  font-size: 12.5px;
  color: var(--text-muted);
  line-height: 1.5;
}

.blog-coming {
  margin: 4px 0 0;
  padding: 14px 16px;
  border: 1px dashed var(--border);
  border-radius: 12px;
  font-size: 13px;
  line-height: 1.55;
  color: var(--text-faint);
}

.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag {
  padding: 4px 12px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--bg-panel);
  font-size: 12.5px;
  color: var(--text-muted);
}

/* ---------- blog post page ---------- */

.post-container {
  max-width: 760px;
  margin: 0 auto;
  padding: 0 24px 64px;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 40px;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-muted);
}

.back-link:hover { color: var(--accent); opacity: 1; }

.post { margin-top: 28px; }

.post h1 {
  margin: 0;
  font-size: 30px;
  font-weight: 700;
  letter-spacing: -.02em;
  line-height: 1.25;
}

.post-meta {
  margin: 12px 0 0;
  font-size: 13.5px;
  color: var(--text-faint);
  display: flex;
  gap: 14px;
  align-items: center;
}

.post-content { margin-top: 32px; color: var(--text-muted); }

.post-content h2 {
  margin: 36px 0 12px;
  font-size: 20px;
  font-weight: 650;
  color: var(--text);
  letter-spacing: -.01em;
}

.post-content p { margin: 14px 0; }

.post-content img,
.post-content video {
  max-width: 100%;
  border-radius: 12px;
  border: 1px solid var(--border);
  display: block;
  margin: 20px auto;
}

.post-content figcaption {
  text-align: center;
  font-size: 13px;
  color: var(--text-faint);
  margin-top: -10px;
  margin-bottom: 20px;
}

.post-content code {
  font-family: "SF Mono", Menlo, Consolas, monospace;
  font-size: 13px;
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 1.5px 6px;
}

.post-content pre {
  background: var(--bg-panel);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px 18px;
  overflow-x: auto;
}

.post-content pre code { background: none; border: none; padding: 0; }

.post-content blockquote {
  margin: 20px 0;
  padding: 4px 20px;
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  border-radius: 0 10px 10px 0;
  color: var(--text);
}

/* ---------- footer ---------- */

.site-footer {
  margin-top: 72px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  font-size: 13px;
  color: var(--text-faint);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px;
}

/* ---------- responsive ---------- */

@media (max-width: 1020px) {
  .layout {
    display: block;
  }

  .side-col {
    position: static;
    margin-top: 56px;
  }
}

@media (max-width: 720px) {
  .intro {
    flex-direction: column;
    gap: 28px;
    margin-top: 36px;
  }

  .portrait { flex: none; }

  .portrait img { width: 132px; height: 132px; border-radius: 14px; }

  .pub {
    flex-direction: column;
    gap: 14px;
    padding: 18px 14px;
    margin: 0 -14px;
  }

  .pub-thumb {
    flex: none;
    width: 100%;
    max-width: 420px;
  }

  .news-list .date { flex-basis: 64px; }
}