/* Ni Lab — austere academic site. No webfonts, no CDN. */

:root {
  --ink: #222222;
  --text: #474747;
  --muted: #7a7a7a;
  --line: #d4d4d4;
  --bg: #ffffff;
  --accent: #2f6f69;
  --max: 42rem;
  --font: "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei",
    "Segoe UI", system-ui, -apple-system, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  font-size: 17px;
  line-height: 1.7;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; height: auto; display: block; }
a { color: var(--accent); text-decoration: underline; text-underline-offset: 3px; }
a:hover { color: var(--ink); }
h1, h2, h3 { color: var(--ink); font-weight: 500; line-height: 1.35; margin: 0 0 0.6em; }
h1 { font-size: 1.85rem; letter-spacing: 0.02em; }
h2 { font-size: 1.15rem; letter-spacing: 0.08em; text-transform: none; }
p { margin: 0 0 1.1em; }
p:last-child { margin-bottom: 0; }
em { font-style: italic; }
strong { font-weight: 600; color: var(--ink); }

.sr-only {
  position: absolute; width: 1px; height: 1px; margin: -1px; padding: 0;
  border: 0; clip: rect(0 0 0 0); overflow: hidden;
}
.skip-link {
  position: absolute; left: -999px; top: 8px; z-index: 20;
  background: var(--ink); color: #fff; padding: 8px 14px;
}
.skip-link:focus { left: 12px; color: #fff; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 1.25rem; }
.page { padding: 2.5rem 0 4.5rem; }
.lede { font-size: 1.02rem; color: var(--ink); }
.muted { color: var(--muted); }
.rule {
  border: 0; height: 1px; background: var(--line);
  margin: 2.25rem 0;
}
.rule-short { width: 3rem; margin-left: 0; }

/* Header */
.site-header { padding: 1.75rem 0 0.5rem; }
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  gap: 1rem; flex-wrap: wrap;
}
.brand {
  color: var(--ink); text-decoration: none; font-weight: 500;
  letter-spacing: 0.18em; text-transform: uppercase; font-size: 0.95rem;
}
.brand span {
  display: block; letter-spacing: 0.22em; font-size: 0.62rem;
  color: var(--muted); font-weight: 400; margin-top: 0.2rem;
  text-transform: none;
}
.brand:hover { color: var(--accent); }
.site-nav { display: flex; flex-wrap: wrap; gap: 0.4rem; }
.site-nav a {
  color: var(--text); text-decoration: none;
  font-size: 0.72rem; letter-spacing: 0.12em;
  border: 1px solid var(--line); border-radius: 999px;
  padding: 0.38rem 0.85rem; line-height: 1.2;
}
.site-nav a:hover,
.site-nav a[aria-current="page"] {
  border-color: var(--accent); color: var(--accent);
}
.nav-toggle {
  display: none; background: none; border: 1px solid var(--line);
  width: 2.4rem; height: 2.4rem; border-radius: 999px; padding: 0;
  cursor: pointer; position: relative;
}
.nav-toggle span {
  position: absolute; left: 0.6rem; right: 0.6rem; height: 1px;
  background: var(--ink);
}
.nav-toggle span:nth-child(1) { top: 0.8rem; }
.nav-toggle span:nth-child(2) { top: 1.15rem; }
.nav-toggle span:nth-child(3) { top: 1.5rem; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 1.5rem 0 2.5rem;
  font-size: 0.85rem; color: var(--muted);
}
.site-footer p { margin: 0 0 0.35em; }
.site-footer a { color: var(--muted); text-decoration: none; }
.site-footer a:hover { color: var(--accent); text-decoration: underline; }

/* Home */
.kicker {
  display: block; font-size: 0.72rem; letter-spacing: 0.22em;
  text-transform: uppercase; color: var(--muted); margin-bottom: 0.85rem;
}
.goals { list-style: none; margin: 0; padding: 0; }
.goals > li { margin: 0 0 1.75rem; }
.goals h3 {
  font-size: 0.95rem; letter-spacing: 0.06em; margin-bottom: 0.35rem;
}
.goals p { font-size: 0.98rem; }

/* About / lists */
.plain-list { list-style: none; margin: 0; padding: 0; }
.plain-list li {
  padding: 0.7rem 0; border-bottom: 1px solid #eee;
}
.plain-list li:last-child { border-bottom: 0; }
.plain-list .when {
  display: block; font-size: 0.78rem; letter-spacing: 0.08em;
  color: var(--muted); margin-bottom: 0.15rem;
}

/* Team */
.person { margin-bottom: 1.5rem; }
.person h3 { margin-bottom: 0.15rem; }
.person .role { color: var(--muted); font-size: 0.92rem; margin-bottom: 0.7rem; }
.team-photo { margin: 1.5rem 0 0.6rem; }
.team-photo img { width: 100%; }
.team-photo figcaption {
  font-size: 0.82rem; color: var(--muted); margin-top: 0.55rem;
}

/* Publications */
.pub-list { list-style: none; margin: 0; padding: 0; }
.pub-list li {
  padding: 1rem 0; border-bottom: 1px solid #eee;
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 1.1rem;
  align-items: start;
}
.pub-list li:last-child { border-bottom: 0; }
.pub-list .pub-figure {
  margin: 0;
  width: 100%;
  border-radius: 6px;
  overflow: hidden;
  background: #fff;
  border: 1px solid #eee;
}
.pub-list .pub-figure img {
  width: 100%; height: auto; display: block;
}
.pub-list .pub-body { min-width: 0; }
@media (max-width: 640px) {
  .pub-list li { grid-template-columns: 1fr; }
}
.pub-list .year {
  display: block; font-size: 0.75rem; letter-spacing: 0.12em;
  color: var(--muted); margin-bottom: 0.2rem;
}
.pub-list .title { color: var(--ink); text-decoration: none; }
.pub-list .title:hover { color: var(--accent); text-decoration: underline; }
.pub-list .meta { font-size: 0.88rem; color: var(--muted); margin-top: 0.25rem; }
.pub-list .summary {
  margin: 0.55rem 0 0.4rem; color: var(--text); font-size: 0.96rem;
}
.pub-list .significance {
  margin: 0 0 0.2rem; color: var(--ink); font-size: 0.9rem;
  border-left: 2px solid var(--accent); padding-left: 0.6rem;
}

/* Contact */
.contact-list { list-style: none; margin: 0; padding: 0; }
.contact-list li { padding: 0.45rem 0; }
.contact-list span {
  display: block; font-size: 0.75rem; letter-spacing: 0.1em;
  color: var(--muted); margin-bottom: 0.1rem;
}

@media (max-width: 640px) {
  body { font-size: 16px; }
  h1 { font-size: 1.5rem; }
  .nav-toggle { display: block; margin-left: auto; }
  .site-nav {
    display: none; width: 100%; flex-direction: column;
  }
  body.nav-open .site-nav { display: flex; }
}

/* 成员网格 */
.member-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.5rem 2rem;
  margin-bottom: 2rem;
}
.member-grid .person { margin-bottom: 0.8rem; }

/* 个人简介照片 */
.profile-photo {
  float: left;
  width: 160px;
  height: auto;
  margin: 0 1.4rem 0.8rem 0;
  border-radius: 4px;
  box-shadow: 0 1px 6px rgba(0, 0, 0, .12);
}
@media (max-width: 640px) {
  .profile-photo {
    float: none;
    display: block;
    margin: 0 0 1rem;
  }
}

/* 资源与工具：成员专属提示 */
.members-only {
  display: inline-block;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: #8a4b0f;
  background: #fdf3e3;
  border: 1px solid #f0d9b5;
  border-radius: 999px;
  padding: 0.12rem 0.55rem;
  margin-bottom: 0.6rem;
}