/* Tong Zheng — Academic Homepage */

:root {
  --bg: #faf9f7;
  --surface: #ffffff;
  --text: #1a1a1a;
  --text-muted: #5c5c5c;
  --accent: #8b2942;
  --accent-hover: #6d1f33;
  --border: #e8e4df;
  --link: #8b2942;
  --link-hover: #6d1f33;
  --badge-new: #c45c26;
  --font-serif: "Source Serif 4", Georgia, "Times New Roman", serif;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --max-width: 720px;
  --radius: 6px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--link);
  text-decoration: none;
  transition: color 0.15s ease;
}

a:hover {
  color: var(--link-hover);
  text-decoration: underline;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 2.5rem 0 2rem;
}

.profile {
  display: flex;
  align-items: flex-start;
  gap: 1.75rem;
}

.profile-photo {
  width: 140px;
  height: 140px;
  object-fit: cover;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  flex-shrink: 0;
}

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

.header-inner {
  display: flex;
  align-items: flex-start;
  gap: 1.5rem;
}

.name {
  font-family: var(--font-serif);
  font-size: 2rem;
  font-weight: 700;
  margin: 0 0 0.35rem;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.name-cn {
  font-weight: 400;
  color: var(--text-muted);
  font-size: 0.85em;
}

.contact {
  margin: 0 0 0.75rem;
  font-size: 0.95rem;
}

.contact a {
  color: var(--text-muted);
}

.contact a:hover {
  color: var(--accent);
}

.profile-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.25rem;
  font-size: 0.9rem;
  font-weight: 500;
}

.profile-links a {
  color: var(--accent);
}

.profile-links a:hover {
  color: var(--accent-hover);
}

/* Sections */
main {
  padding: 2rem 0 3rem;
}

.section {
  margin-bottom: 2.75rem;
}

.section h2 {
  font-family: var(--font-serif);
  font-size: 1.35rem;
  font-weight: 600;
  margin: 0 0 1rem;
  padding-bottom: 0.4rem;
  border-bottom: 2px solid var(--border);
  color: var(--text);
}

.section h2 .muted {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 400;
  color: var(--text-muted);
}

.section p {
  margin: 0 0 1rem;
}

.research-summary {
  margin-top: 0.25rem;
}

.research-intro {
  margin: 0 0 1.1rem;
  padding-left: 1rem;
  border-left: 4px solid var(--accent);
  color: var(--text);
  line-height: 1.65;
}

.research-block {
  margin: 0 0 1rem;
  font-size: 0.95rem;
  line-height: 1.7;
}

.research-block:last-child {
  margin-bottom: 0;
}

.research-theme {
  font-weight: 600;
  color: var(--accent);
}

.research-summary .paper-link {
  color: #1a56a8;
  font-weight: 500;
  text-decoration: none;
}

.research-summary .paper-link:hover {
  color: #0d3d7a;
  text-decoration: underline;
}

/* Experience */
.experience-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.experience-list li {
  margin-bottom: 0.65rem;
  font-size: 0.95rem;
  line-height: 1.5;
}

.experience-meta {
  color: var(--text-muted);
  font-size: 0.88rem;
}

.experience-meta::before {
  content: " · ";
}

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

.news-list li {
  display: grid;
  grid-template-columns: 7.5rem 1fr;
  gap: 0.75rem 1rem;
  padding: 0.55rem 0;
  border-bottom: 1px solid var(--border);
  font-size: 0.92rem;
}

.news-list li:last-child {
  border-bottom: none;
}

.news-list time {
  font-variant-numeric: tabular-nums;
  color: var(--text-muted);
  font-size: 0.85rem;
  white-space: nowrap;
}

.news-collapse {
  margin-top: 0.25rem;
}

.news-collapse summary {
  cursor: pointer;
  color: var(--accent);
  font-size: 0.9rem;
  font-weight: 500;
  list-style: none;
  padding: 0.6rem 0;
  user-select: none;
}

.news-collapse summary::-webkit-details-marker {
  display: none;
}

.news-collapse summary::before {
  content: "▸ ";
  display: inline-block;
  transition: transform 0.15s ease;
}

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

.news-collapse summary:hover {
  color: var(--accent-hover);
}

/* Publications */
.pub {
  margin-bottom: 1.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}

.pub:last-child {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.pub-featured {
  position: relative;
}

.badge {
  display: inline-block;
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: 0.15em 0.45em;
  border-radius: 3px;
  margin-bottom: 0.35rem;
  vertical-align: middle;
}

.badge-new {
  background: #fef3eb;
  color: var(--badge-new);
  border: 1px solid #f5d4bc;
}

.pub-title {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  font-weight: 600;
  margin: 0 0 0.25rem;
  line-height: 1.4;
}

.pub-links {
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 500;
  white-space: nowrap;
}

.pub-links a {
  margin-left: 0.15rem;
}

.pub-venue {
  margin: 0 0 0.35rem;
  font-size: 0.88rem;
  color: var(--accent);
  font-weight: 500;
}

.pub-authors {
  margin: 0;
  font-size: 0.88rem;
  color: var(--text-muted);
  line-height: 1.5;
}

.pub-authors strong {
  color: var(--text);
  font-weight: 600;
}

/* Honors */
.honors-list {
  margin: 0;
  padding-left: 1.25rem;
}

.honors-list li {
  margin-bottom: 0.4rem;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 1.5rem 0 2rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.site-footer p {
  margin: 0;
}

.site-footer a {
  color: var(--text-muted);
}

.site-footer a:hover {
  color: var(--accent);
}

/* Responsive */
@media (max-width: 540px) {
  .profile {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }

  .profile-links {
    justify-content: center;
  }

  .name {
    font-size: 1.65rem;
  }

  .news-list li {
    grid-template-columns: 1fr;
    gap: 0.2rem;
  }

  .news-list time {
    font-weight: 500;
  }
}