/* ═══════════════════════════════════════════════════════════
   Shuxin Cao — personal site
   Following the classic academic-homepage format (à la
   zhengyiluo.com / yiqingxu.org): plain, system fonts, a single
   ~880px column, gray hairlines, blue links. No frills.
   ═══════════════════════════════════════════════════════════ */

:root {
  --paper:   #ffffff;
  --ink:     #000000;
  --ink-2:   #333333;
  --muted:   #828282;
  --rule:    #e6e6e6;
  --link:       #5b40c6; /* blend of lhy.xyz's #0076df and eeching's #b509ac */
  --link-hover: #44309a;

  --sans: "Roboto", -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  --slab: "Roboto Slab", "Roboto", Georgia, serif;
  --mono: SFMono-Regular, Menlo, Consolas, monospace;

  /* about-section treatment, after ruoshiliu.github.io */
  --lato: "Lato", -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
  --ruoshi-link: #6f81c9;

  --maxw: 880px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-weight: 400;
  font-size: 17px;
  line-height: 1.58;
  padding-bottom: 40px;
}

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

hr { border: none; border-top: 1px solid var(--rule); margin: 0; }

h2 { font-family: var(--slab); font-weight: 700; font-size: 25px; margin: 0 0 14px; letter-spacing: normal; }
h3 { font-family: var(--slab); font-weight: 700; font-size: 18.5px; margin: 0 0 2px; }
h4 { font-weight: 700; font-size: 12.5px; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); margin: 0 0 6px; }

.skip { position: absolute; left: -9999px; top: 0; background: var(--link); color: #fff; padding: 10px 16px; z-index: 99; }
.skip:focus { left: 12px; top: 12px; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }

/* ── nav ────────────────────────────────────────────────── */
.navbar {
  position: sticky; top: 0; z-index: 20;
  background: rgba(255,255,255,.96);
  backdrop-filter: saturate(1.6) blur(6px);
  border-bottom: 1px solid var(--rule);
}
.navbar-inner { display: flex; align-items: center; justify-content: space-between; height: 54px; }
.brand { font-weight: 700; color: var(--ink); font-size: 19px; }
.brand:hover { text-decoration: none; color: var(--muted); }

.nav-links { list-style: none; display: flex; gap: 22px; margin: 0; padding: 0; }
.nav-links a {
  color: var(--muted); font-size: 16px; letter-spacing: .01em;
  padding: 4px 0; border-bottom: 2px solid transparent;
}
.nav-links a:hover { color: var(--ink); text-decoration: none; }
.nav-links a.active { color: var(--ink); font-weight: 700; border-bottom-color: var(--link); }

.navbar-toggler {
  display: none; flex-direction: column; gap: 4px;
  background: none; border: 0; padding: 8px; cursor: pointer;
}
.navbar-toggler span { width: 20px; height: 2px; background: var(--ink); border-radius: 1px; transition: transform .2s, opacity .2s; }
.navbar-toggler[aria-expanded="true"] span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
.navbar-toggler[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.navbar-toggler[aria-expanded="true"] span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

/* ── page sections ──────────────────────────────────────── */
.page { padding-top: 30px; }
.post, .news, .content, .publications, .experience, .photography { padding: 28px 0; }

.post-header { margin-bottom: 18px; }
.post-title { font-family: var(--lato); font-weight: 300; font-size: 34px; color: #272727; }
.post-title:hover { text-decoration: none; }
.post-title b { font-weight: 700; }

.identity { margin: 8px 0 0; color: #272727; font-size: 16px; line-height: 1.55; font-family: var(--lato); font-weight: 300; }
.identity .email { font-family: var(--lato); font-size: 15px; color: var(--muted); }

/* ── about intro: photo floats inline with the text, after ruoshiliu.github.io ── */
.intro-flow { font-family: var(--lato); overflow: hidden; } /* overflow:hidden clears the float */
.intro-flow p {
  text-align: left; margin: 0 0 16px; color: #272727;
  font-size: 17.5px; font-weight: 300; line-height: 1.6;
}
.intro-flow a { color: var(--ruoshi-link); font-weight: 700; }
.intro-flow a:hover { color: var(--ruoshi-link); text-decoration: underline; }

.profile-img-round {
  float: right;
  width: 210px; height: auto;
  margin: -6px 0 16px 24px;
  border-radius: 6px;
  border: 1px solid var(--rule);
  filter: brightness(1.12) contrast(0.96) saturate(0.94);
}

.contact-row { margin-top: 4px; font-size: 15.5px; }
.contact-row a { color: var(--ruoshi-link); font-weight: 700; }
.contact-row a:hover { color: var(--ruoshi-link); }
.contact-row .sep { color: var(--rule); margin: 0 9px; }
.contact-row .note { font-size: 12.5px; color: var(--muted); font-style: italic; }

/* ── news: matches the about/intro treatment (Lato, after ruoshiliu.github.io) ── */
#news h2 { font-family: var(--lato); font-weight: 700; color: #272727; }
.table-wrap table { width: 100%; border-collapse: collapse; }
.table-wrap td { padding: 2px 0; vertical-align: top; font-size: 16px; color: #272727; font-family: var(--lato); font-weight: 300; }
.table-wrap .date { width: 78px; color: var(--muted); font-variant-numeric: tabular-nums; white-space: nowrap; }
.table-wrap a { color: var(--ruoshi-link); font-weight: 700; }
.table-wrap a:hover { color: var(--ruoshi-link); text-decoration: underline; }
.news-more { display: none; }
.news.expanded .news-more { display: table-row; }
.show-more {
  margin-top: 6px; background: none; border: 0; padding: 0;
  color: var(--ruoshi-link); font-size: 13.5px; cursor: pointer; font-family: var(--lato); font-weight: 700;
}
.show-more:hover { text-decoration: underline; }
.news.expanded .show-more { display: none; }

/* ── research ───────────────────────────────────────────── */
.intro { color: var(--ink-2); max-width: 68ch; font-size: 17px; }
.research-list { list-style: none; padding: 0; margin: 18px 0 0; counter-reset: none; }
.research-list li { margin-bottom: 16px; color: var(--ink-2); max-width: 68ch; font-size: 17px; }
.research-list b { color: var(--ink); }

/* ── publications ───────────────────────────────────────── */
.pub-tabs { display: flex; gap: 28px; border-bottom: 1px solid var(--rule); margin-bottom: 20px; }
.pub-tab {
  background: none; border: 0; cursor: pointer; font-family: var(--sans);
  padding: 0 0 10px; margin-bottom: -1px;
  font-size: 14px; font-weight: 700; text-transform: uppercase; letter-spacing: .06em;
  color: var(--muted); border-bottom: 2px solid transparent;
}
.pub-tab:hover { color: var(--ink); }
.pub-tab.active { color: var(--ink); border-bottom-color: var(--link); }

.paper-entry { display: flex; gap: 20px; padding: 18px 0; border-bottom: 1px solid var(--rule); }
.paper-entry:last-child { border-bottom: 0; padding-bottom: 0; }

.paper-thumb {
  flex: 0 0 150px; width: 150px; height: 112px;
  border-radius: 4px; overflow: hidden;
  background: #f4f4f4; border: 1px solid var(--rule);
  display: grid; place-items: center; position: relative;
}
.paper-thumb::after {
  content: attr(data-fallback);
  font-family: var(--mono); font-size: 11px; letter-spacing: .04em; color: var(--muted);
}
.paper-thumb img { position: relative; z-index: 1; width: 100%; height: 100%; object-fit: cover; display: block; }

.paper-info { list-style: none; padding: 0; margin: 0; min-width: 0; }
.paper-info li { margin: 0 0 4px; }
.paper-info .title { font-weight: 700; font-size: 18.5px; line-height: 1.32; color: var(--ink); }
.paper-info .authors { font-size: 15.5px; color: var(--ink-2); }
.paper-info .venue { font-size: 14.5px; color: var(--muted); }
.paper-info .pub-links { margin-top: 7px; }
.paper-info .pub-links a { font-size: 14.5px; margin-right: 9px; }

/* publications: matches the about/news treatment (Lato, after ruoshiliu.github.io) */
#publications h2 { font-family: var(--lato); font-weight: 700; color: #272727; }
#publications .pub-tab { font-family: var(--lato); color: var(--muted); }
#publications .pub-tab.active,
#publications .pub-tab:hover { color: #272727; }
#publications .pub-tab.active { border-bottom-color: var(--ruoshi-link); }
#publications .paper-info .title { font-family: var(--lato); font-weight: 700; color: #272727; }
#publications .paper-info .authors { font-family: var(--lato); font-weight: 300; color: #272727; }
#publications .paper-info .authors b { font-weight: 700; }
#publications .paper-info .venue { font-family: var(--lato); font-weight: 300; color: var(--muted); }
#publications .paper-info .pub-links a { color: var(--ruoshi-link); font-weight: 700; font-family: var(--lato); }
#publications .paper-info .pub-links a:hover { color: var(--ruoshi-link); text-decoration: underline; }

/* ── experience ─────────────────────────────────────────── */
.post-list { list-style: none; margin: 0; padding: 0; }
.post-list li { border-bottom: 1px solid var(--rule); padding: 18px 0; }
.post-list li:first-child { padding-top: 0; }
.post-list li:last-child { border-bottom: 0; padding-bottom: 0; }
.post-meta { color: var(--muted); font-size: 14px; }
.post-list h3 { margin-top: 5px; }
.where { font-weight: 400; color: var(--muted); font-size: 14.5px; }
.post-list p { margin: 5px 0 0; color: var(--ink-2); font-size: 15.5px; max-width: 68ch; }

/* ── photography ────────────────────────────────────────── */
.gallery { columns: 3; column-gap: 14px; margin: 22px 0 30px; }
.gallery figure { break-inside: avoid; margin: 0 0 16px; }
.gallery img {
  width: 100%; display: block; border-radius: 5px;
  box-shadow: 0 1px 3px rgba(0,0,0,.12);
  cursor: zoom-in;
}
.gallery figcaption { font-size: 12.5px; color: var(--muted); margin-top: 6px; text-align: center; }

.ph-empty {
  break-inside: avoid; margin: 0 0 14px;
  border: 1px dashed var(--rule); border-radius: 5px;
  display: grid; place-items: center; text-align: center;
  color: var(--muted); font-family: var(--mono); font-size: 11px; line-height: 1.8;
  padding: 18px; background: #fafafa;
}
.ph-empty span { display: block; font-size: 20px; opacity: .4; margin-bottom: 6px; }

.hobby-row { display: flex; gap: 30px; flex-wrap: wrap; border-top: 1px solid var(--rule); padding-top: 22px; }
.hobby { flex: 1 1 200px; }
.hobby p { margin: 0; color: var(--ink-2); font-size: 15.5px; }

/* ── reviewer: matches the about/news/publications treatment (Lato, after ruoshiliu.github.io) ── */
#reviewer h2 { font-family: var(--lato); font-weight: 700; color: #272727; }
#reviewer p { font-family: var(--lato); font-weight: 300; font-size: 17.5px; color: #272727; margin: 0; }

/* ── footer ─────────────────────────────────────────────── */
.foot { border-top: 1px solid var(--rule); padding-top: 24px; font-size: 13px; color: var(--muted); }
.foot p { margin: 0; }

/* ── lightbox ───────────────────────────────────────────── */
.lightbox { position: fixed; inset: 0; z-index: 100; background: rgba(10,10,10,.94); display: grid; place-items: center; padding: 40px; }
.lightbox[hidden] { display: none; }
.lightbox img { max-width: 100%; max-height: 84vh; object-fit: contain; border-radius: 3px; }
.lb-cap { position: absolute; bottom: 18px; left: 0; right: 0; text-align: center; color: #ccc; font-size: 12.5px; margin: 0; }
.lightbox button { position: absolute; background: none; border: 0; color: #fff; cursor: pointer; font-size: 32px; line-height: 1; opacity: .6; padding: 12px; }
.lightbox button:hover { opacity: 1; }
.lb-close { top: 12px; right: 18px; }
.lb-prev { left: 6px; top: 50%; transform: translateY(-50%); font-size: 42px; }
.lb-next { right: 6px; top: 50%; transform: translateY(-50%); font-size: 42px; }

/* ── responsive ─────────────────────────────────────────── */
@media (max-width: 760px) {
  .navbar-toggler { display: flex; }
  .nav-links {
    position: absolute; top: 54px; left: 0; right: 0;
    background: #fff; border-bottom: 1px solid var(--rule);
    flex-direction: column; gap: 0; padding: 8px 22px;
    display: none;
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 11px 0; border-bottom: 1px solid var(--rule); width: 100%; }
  .nav-links li:last-child a { border-bottom: 0; }

  .profile-img-round { width: 125px; height: auto; margin: -4px 0 12px 16px; }

  .paper-entry { flex-direction: column; gap: 10px; }
  .paper-thumb { width: 100%; }

  .gallery { columns: 2; }
}
@media (max-width: 480px) {
  .gallery { columns: 1; }
  .lightbox { padding: 16px; }
}