/* ===========================================================================
   lingyunzhang.com — text-first academic homepage.
   One stylesheet, no framework, no webfonts. Green accent from the Chaitin
   palette; everything else is typography and hairlines.
   =========================================================================== */

:root {
  --bg: #ffffff;
  --bg-soft: #f9fbf8;
  --bg-tint: #eef4ec;
  --ink: #121715;
  --ink-2: #2b3531;
  --muted: #5b6761;
  --muted-2: #8b958f;
  --line: #e5eae4;
  --line-strong: #cfd8cd;
  --green: #2f8f45;
  --green-soft: #4bad52;
  --green-light: #7aba4a;
  --green-wash: #f1f7ef;

  --narrow: 780px;
  --wide: 1120px;
  --radius: 10px;

  --font-sans: "Helvetica Neue", Helvetica, -apple-system, BlinkMacSystemFont,
    "Segoe UI", Inter, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
    Arial, sans-serif;
  --font-display: "Iowan Old Style", "Palatino Linotype", Palatino, "Book Antiqua",
    Georgia, "Songti SC", serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 76px;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 16.5px;
  font-weight: 400;
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img,
svg {
  max-width: 100%;
  display: block;
}

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

h1,
h2,
h3,
h4 {
  margin: 0;
  font-weight: 600;
  line-height: 1.28;
  letter-spacing: -0.008em;
}

p {
  margin: 0;
}

ul,
ol,
dl,
dd {
  margin: 0;
  padding: 0;
  list-style: none;
}

strong,
b {
  font-weight: 600;
}

::selection {
  background: var(--green-wash);
  color: var(--green);
}

:focus-visible {
  outline: 2px solid var(--green-soft);
  outline-offset: 3px;
}

/* ------------------------------------------------------------------ layout */

.wrap {
  width: 100%;
  margin: 0 auto;
  padding: 0 26px;
}

.wrap.narrow {
  max-width: var(--narrow);
}

.wrap.wide {
  max-width: var(--wide);
  padding: 0 30px;
}

.site-main {
  min-height: 64vh;
  padding-bottom: 40px;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(255, 255, 255, 0.88);
  backdrop-filter: saturate(180%) blur(12px);
  -webkit-backdrop-filter: saturate(180%) blur(12px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  gap: 22px;
  height: 62px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  margin-right: auto;
  font-family: var(--font-display);
  font-size: 1.02rem;
  letter-spacing: 0.005em;
}

.brand-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--green-soft), var(--green-light));
}

.nav {
  display: flex;
  align-items: center;
  gap: 22px;
}

.nav-link {
  font-size: 0.92rem;
  color: var(--muted);
  transition: color 0.18s ease;
}

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

.nav-link.is-active {
  color: var(--ink);
  font-weight: 500;
}

.profile-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 15px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  font-size: 0.86rem;
  font-weight: 500;
  color: var(--ink-2);
  background: #fff;
  transition: border-color 0.18s ease, color 0.18s ease, box-shadow 0.18s ease;
}

.profile-btn:hover {
  border-color: var(--green-soft);
  color: var(--green);
  box-shadow: 0 0 0 3px var(--green-wash);
}

.profile-arrow {
  font-size: 0.8rem;
  transition: transform 0.18s ease;
}

.profile-btn:hover .profile-arrow {
  transform: translate(2px, -2px);
}

/* ---------------------------------------------------------------- masthead */

.masthead {
  padding: 68px 0 30px;
}

.masthead-name {
  font-family: var(--font-display);
  font-size: clamp(2.1rem, 4.6vw, 2.75rem);
  font-weight: 500;
  letter-spacing: -0.022em;
  line-height: 1.1;
}

.masthead-role {
  margin-top: 10px;
  font-size: 1.02rem;
  color: var(--muted);
}

.masthead-links {
  margin-top: 16px;
  font-size: 0.93rem;
  color: var(--muted-2);
}

.masthead-link {
  color: var(--ink-2);
  border-bottom: 1px solid transparent;
  transition: color 0.16s ease, border-color 0.16s ease;
}

.masthead-link:hover {
  color: var(--green);
  border-color: var(--green-soft);
}

.sep {
  color: var(--line-strong);
  white-space: pre;
}

.masthead-interests {
  margin-top: 16px;
  display: flex;
  flex-wrap: wrap;
  gap: 4px 12px;
  align-items: baseline;
}

.interests-label {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted-2);
}

.interests-items {
  font-size: 0.92rem;
  color: var(--ink-2);
}

.eyebrow {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--green);
  margin-bottom: 8px;
}

/* ------------------------------------------------------------------ blocks */

.block {
  padding: 34px 0 30px;
  border-top: 1px solid var(--line);
}

.block-title {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 18px;
  font-family: var(--font-display);
  font-size: 1.42rem;
  font-weight: 500;
  letter-spacing: -0.015em;
}

.block-title::before {
  content: "";
  width: 3px;
  height: 18px;
  border-radius: 2px;
  background: linear-gradient(180deg, var(--green-soft), var(--green-light));
}

.block-count {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 400;
  color: var(--muted-2);
  padding: 1px 7px;
  border: 1px solid var(--line);
  border-radius: 999px;
}

.block-more {
  margin-top: 16px;
  font-size: 0.9rem;
}

.more-link {
  color: var(--muted);
  transition: color 0.16s ease;
}

.more-link:hover {
  color: var(--green);
}

.about-p {
  color: var(--ink-2);
}

.about-p + .about-p {
  margin-top: 14px;
}

.empty {
  color: var(--muted-2);
  font-style: italic;
}

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

.news-list {
  display: flex;
  flex-direction: column;
  gap: 9px;
}

.news-item {
  display: grid;
  grid-template-columns: 92px minmax(0, 1fr);
  gap: 14px;
  align-items: baseline;
  font-size: 0.96rem;
}

.news-date {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.02em;
  color: var(--muted-2);
  padding-top: 2px;
}

.news-text {
  color: var(--ink-2);
}

a.news-text {
  border-bottom: 1px solid transparent;
  transition: color 0.16s ease, border-color 0.16s ease;
}

a.news-text:hover {
  color: var(--green);
  border-color: var(--green-soft);
}

/* ------------------------------------------------------------------ papers */

.paper-list {
  display: flex;
  flex-direction: column;
}

.paper {
  padding: 20px 0;
  border-top: 1px solid var(--line);
}

.paper:first-child {
  border-top: 0;
  padding-top: 0;
}

.paper-title {
  font-size: 1.04rem;
  font-weight: 600;
  letter-spacing: -0.006em;
  line-height: 1.42;
}

.paper.is-selected .paper-title::after {
  content: "";
  display: inline-block;
  width: 5px;
  height: 5px;
  margin-left: 8px;
  border-radius: 50%;
  background: var(--green-light);
  vertical-align: middle;
}

.paper-authors {
  margin-top: 5px;
  font-size: 0.92rem;
  color: var(--muted);
}

.author.is-self {
  color: var(--ink);
  font-weight: 600;
}

.paper-venue {
  margin-top: 3px;
  font-size: 0.88rem;
  color: var(--green);
}

.paper-sep {
  color: var(--line-strong);
}

.paper-kind {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.04em;
  color: var(--muted-2);
  text-transform: uppercase;
}

.paper-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  gap: 7px;
  margin-top: 11px;
}

.pill {
  display: inline-flex;
  align-items: center;
  padding: 3px 11px;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 500;
  color: var(--ink-2);
  background: #fff;
  cursor: pointer;
  transition: border-color 0.16s ease, color 0.16s ease, background-color 0.16s ease;
}

.pill:hover {
  border-color: var(--green-soft);
  color: var(--green);
  background: var(--green-wash);
}

.pill-primary {
  background: var(--ink);
  border-color: var(--ink);
  color: #fff;
}

.pill-primary:hover {
  background: var(--green);
  border-color: var(--green);
  color: #fff;
}

.disclosure {
  display: inline-block;
  max-width: 100%;
}

.disclosure summary {
  list-style: none;
}

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

.paper-abstract {
  margin-top: 12px;
  max-width: 74ch;
  font-size: 0.94rem;
  color: var(--muted);
  line-height: 1.68;
  padding: 12px 16px;
  border-left: 2px solid var(--green-wash);
  background: var(--bg-soft);
  border-radius: 0 var(--radius) var(--radius) 0;
}

.disclosure pre {
  margin: 12px 0 0;
  padding: 14px 16px;
  max-width: min(74ch, 100%);
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg-soft);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  line-height: 1.55;
  color: var(--ink-2);
}

/* -------------------------------------------------------------------- work */

.work-list {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.work-item {
  padding-left: 16px;
  border-left: 1px solid var(--line);
}

.work-title {
  font-size: 1rem;
  font-weight: 600;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 10px;
}

.work-title a {
  transition: color 0.16s ease;
}

.work-title a:hover {
  color: var(--green);
}

.work-meta {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.02em;
  color: var(--muted-2);
  font-weight: 400;
}

.work-summary {
  margin-top: 5px;
  font-size: 0.94rem;
  color: var(--muted);
}

/* ------------------------------------------------------------------- posts */

.post-list {
  display: flex;
  flex-direction: column;
}

.post-row {
  display: grid;
  grid-template-columns: 108px minmax(0, 1fr);
  gap: 16px;
  padding: 12px 0;
  border-top: 1px solid var(--line);
}

.post-row:first-child {
  border-top: 0;
  padding-top: 0;
}

.post-date {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--muted-2);
  padding-top: 5px;
}

.post-body {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.post-title {
  font-size: 1rem;
  font-weight: 600;
  transition: color 0.16s ease;
}

.post-title:hover {
  color: var(--green);
}

.post-summary {
  font-size: 0.9rem;
  color: var(--muted);
}

/* -------------------------------------------------------------------- tags */

.tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 9px;
}

.tag {
  padding: 1px 9px;
  border-radius: 999px;
  background: var(--bg-soft);
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 0.71rem;
  color: var(--muted);
}

/* --------------------------------------------------------------- page head */

.page-head {
  padding: 56px 0 26px;
}

.page-title {
  font-family: var(--font-display);
  font-size: clamp(1.9rem, 4vw, 2.4rem);
  font-weight: 500;
  letter-spacing: -0.02em;
}

.page-lede {
  margin-top: 10px;
  max-width: 62ch;
  color: var(--muted);
  font-size: 1rem;
}

.page-meta {
  margin-top: 12px;
  font-family: var(--font-mono);
  font-size: 0.73rem;
  letter-spacing: 0.04em;
  color: var(--muted-2);
}

/* ----------------------------------------------------------------- article */

.article-wrap {
  max-width: 720px;
}

.back-link {
  display: inline-block;
  margin-bottom: 22px;
  font-size: 0.86rem;
  color: var(--muted);
}

.back-link:hover {
  color: var(--green);
}

.article-head {
  padding-bottom: 22px;
  border-bottom: 1px solid var(--line);
}

.article-title {
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 3.6vw, 2.25rem);
  font-weight: 500;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.article-meta {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 14px;
  font-family: var(--font-mono);
  font-size: 0.76rem;
  color: var(--muted-2);
}

.article-foot {
  margin-top: 36px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.dot {
  color: var(--line-strong);
}

/* prose: rendered markdown */
.prose {
  padding: 26px 0 6px;
  color: var(--ink-2);
  line-height: 1.78;
}

.prose > * + * {
  margin-top: 1.1em;
}

.prose h2 {
  margin-top: 2em;
  font-family: var(--font-display);
  font-size: 1.42rem;
  font-weight: 500;
  letter-spacing: -0.015em;
}

.prose h3 {
  margin-top: 1.7em;
  font-size: 1.1rem;
}

.prose a {
  color: var(--green);
  border-bottom: 1px solid rgba(47, 143, 69, 0.28);
}

.prose a:hover {
  border-color: var(--green);
}

.prose ul,
.prose ol {
  padding-left: 1.3em;
}

.prose ul li {
  list-style: disc;
}

.prose ol li {
  list-style: decimal;
}

.prose li + li {
  margin-top: 0.4em;
}

.prose li::marker {
  color: var(--green-soft);
}

.prose blockquote {
  margin: 1.5em 0;
  padding: 2px 0 2px 18px;
  border-left: 2px solid var(--green-light);
  font-family: var(--font-display);
  font-size: 1.06rem;
  color: var(--ink-2);
}

.prose code {
  padding: 1px 6px;
  border-radius: 4px;
  background: var(--bg-tint);
  font-family: var(--font-mono);
  font-size: 0.86em;
}

.prose pre {
  padding: 16px 18px;
  overflow-x: auto;
  border-radius: var(--radius);
  background: #0f1512;
  color: #e9efe9;
  font-size: 0.84rem;
  line-height: 1.6;
}

.prose pre code {
  background: none;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

.prose table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.93rem;
}

.prose th,
.prose td {
  padding: 8px 10px;
  border-bottom: 1px solid var(--line);
  text-align: left;
}

.prose th {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--muted-2);
  font-weight: 500;
}

.prose hr {
  border: 0;
  border-top: 1px solid var(--line);
  margin: 2em 0;
}

.prose img {
  border-radius: var(--radius);
  border: 1px solid var(--line);
}

/* ------------------------------------------------------------------ resume */

.page-head-profile {
  border-bottom: 1px solid var(--line);
}

.page-head-row {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 26px;
}

.page-head-actions {
  display: flex;
  gap: 9px;
  padding-bottom: 4px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 8px 15px;
  border-radius: 999px;
  border: 1px solid var(--line-strong);
  font-size: 0.87rem;
  font-weight: 500;
  color: var(--ink-2);
  background: #fff;
  cursor: pointer;
  font-family: inherit;
  transition: border-color 0.16s ease, color 0.16s ease;
}

.btn:hover {
  border-color: var(--green-soft);
  color: var(--green);
}

.resume-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 250px;
  gap: 52px;
  align-items: start;
  padding: 38px 0 60px;
}

.resume-main {
  display: flex;
  flex-direction: column;
  gap: 34px;
}

.resume-side {
  display: flex;
  flex-direction: column;
  gap: 28px;
  position: sticky;
  top: 92px;
  order: 2;
}

.resume-block-title {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  font-weight: 500;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--muted-2);
  padding-bottom: 9px;
  margin-bottom: 14px;
  border-bottom: 1px solid var(--line);
}

.resume-summary {
  color: var(--ink-2);
}

.contact-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.contact-item {
  display: flex;
  flex-direction: column;
  gap: 1px;
}

.contact-label {
  font-family: var(--font-mono);
  font-size: 0.63rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted-2);
}

.contact-value {
  font-size: 0.9rem;
  color: var(--ink-2);
  word-break: break-word;
}

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

.skill-group + .skill-group {
  margin-top: 14px;
}

.skill-title {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--ink-2);
}

.honor-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 0.9rem;
  color: var(--muted);
}

.honor-list li {
  padding-left: 13px;
  position: relative;
}

.honor-list li::before {
  content: "▹";
  position: absolute;
  left: 0;
  color: var(--green-light);
}

.timeline {
  display: flex;
  flex-direction: column;
  gap: 26px;
}

.timeline-item {
  position: relative;
  padding-left: 20px;
  border-left: 1px solid var(--line);
}

.timeline-item::before {
  content: "";
  position: absolute;
  left: -4.5px;
  top: 9px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #fff;
  border: 2px solid var(--green-soft);
}

.timeline-role {
  font-size: 1.02rem;
  font-weight: 600;
}

.timeline-org {
  color: var(--green);
  font-weight: 500;
}

.timeline-at {
  color: var(--line-strong);
  font-weight: 400;
}

.timeline-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 7px;
  margin-top: 4px;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--muted-2);
}

.timeline-detail {
  margin-top: 7px;
  font-size: 0.93rem;
  color: var(--muted);
}

.bullet-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-top: 10px;
  font-size: 0.94rem;
  color: var(--muted);
}

.bullet-list li {
  position: relative;
  padding-left: 15px;
}

.bullet-list li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: 0.7em;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--line-strong);
}

.plain-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  font-size: 0.93rem;
  color: var(--muted);
}

.plain-list li {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
  align-items: baseline;
}

.plain-year {
  font-family: var(--font-mono);
  font-size: 0.74rem;
  color: var(--muted-2);
}

.plain-venue {
  color: var(--green);
  font-size: 0.86rem;
}

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

.site-footer {
  border-top: 1px solid var(--line);
  background: var(--bg-soft);
  padding: 26px 0;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px 24px;
}

.footer-note {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--muted-2);
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 0.84rem;
  color: var(--muted);
}

.footer-link:hover {
  color: var(--green);
}

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

@media (max-width: 860px) {
  .resume-grid {
    grid-template-columns: minmax(0, 1fr);
    gap: 32px;
  }

  .resume-side {
    position: static;
    order: 0;
  }

  .page-head-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }
}

@media (max-width: 620px) {
  body {
    font-size: 16px;
  }

  .wrap {
    padding: 0 18px;
  }

  .wrap.wide {
    padding: 0 18px;
  }

  .header-inner {
    height: 58px;
    gap: 12px;
  }

  .nav {
    gap: 15px;
  }

  .nav-link {
    font-size: 0.88rem;
  }

  .brand-name {
    font-size: 0.96rem;
  }

  .profile-btn {
    padding: 6px 12px;
    font-size: 0.8rem;
  }

  .masthead {
    padding: 44px 0 22px;
  }

  .masthead-interests {
    flex-direction: column;
    gap: 4px;
  }

  .news-item {
    grid-template-columns: minmax(0, 1fr);
    gap: 2px;
  }

  .post-row {
    grid-template-columns: minmax(0, 1fr);
    gap: 3px;
  }

  .post-date {
    padding-top: 0;
  }

  .footer-inner {
    flex-direction: column;
  }
}

/* ------------------------------------------------------------------- print */

@media print {
  :root {
    --ink: #000;
    --ink-2: #111;
    --muted: #333;
    --muted-2: #555;
    --line: #ddd;
  }

  .site-header,
  .site-footer,
  .page-head-actions,
  .back-link,
  .article-foot,
  .block-more {
    display: none !important;
  }

  body {
    font-size: 11pt;
    line-height: 1.5;
  }

  .wrap {
    max-width: none;
    padding: 0;
  }

  .masthead {
    padding: 0 0 12pt;
  }

  .block {
    padding: 10pt 0;
  }

  .resume-grid {
    grid-template-columns: 190px minmax(0, 1fr);
    gap: 20pt;
    padding: 0;
  }

  .resume-side {
    position: static;
    order: 2;
  }

  .btn,
  .pill {
    border: 0;
    padding: 0;
    background: none;
  }

  a {
    color: #000;
  }

  details {
    display: none;
  }
}