/* ------------------------------------------------------------------
   chituan.github.io — one stylesheet for the whole site.
   Classic academic: serif, single column, warm paper, navy accent.
   No JavaScript, no web fonts, no external requests.
------------------------------------------------------------------ */

:root {
  --bg:     #fdfcf9;
  --text:   #1c1b19;
  --muted:  #6b6862;
  --accent: #14315c;
  --rule:   #e3ded3;
  --serif:  "Iowan Old Style", "Charter", "Palatino Linotype", Palatino,
            "Book Antiqua", Georgia, serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg:     #17161b;
    --text:   #e9e6e0;
    --muted:  #9c968d;
    --accent: #93b3de;
    --rule:   #2d2b33;
  }
}

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

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0 auto;
  max-width: 46rem;              /* ~720px */
  padding: 3.5rem 1.75rem 4rem;
  background: var(--bg);
  color: var(--text);
  font-family: var(--serif);
  font-size: 18px;
  line-height: 1.65;
  font-kerning: normal;
  text-rendering: optimizeLegibility;
}

/* ---------- links ---------- */

a {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-thickness: 0.06em;
  text-underline-offset: 0.16em;
}
a:hover { text-decoration-thickness: 0.11em; }

/* ---------- header + nav ---------- */

.site-header {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.5rem 1.5rem;
  padding-bottom: 0.9rem;
  border-bottom: 1px solid var(--rule);
  margin-bottom: 3rem;
}

.site-name {
  font-size: 1.1rem;
  letter-spacing: 0.03em;
  color: var(--text);
  text-decoration: none;
}
.site-name:hover { color: var(--accent); }

.site-nav a {
  margin-left: 1.35rem;
  font-variant: small-caps;
  letter-spacing: 0.06em;
  font-size: 1rem;
  color: var(--muted);
  text-decoration: none;
  padding-bottom: 0.15rem;
  border-bottom: 1px solid transparent;
}
.site-nav a:first-child { margin-left: 0; }
.site-nav a:hover { color: var(--text); }
.site-nav a[aria-current="page"] {
  color: var(--text);
  border-bottom-color: var(--accent);
}

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

h1 {
  font-size: 2.05rem;
  font-weight: normal;
  line-height: 1.2;
  letter-spacing: 0.005em;
  margin: 0 0 0.35rem;
}

.subtitle {
  color: var(--muted);
  font-size: 1.05rem;
  line-height: 1.45;
  margin: 0 0 2rem;
}

h2 {
  font-size: 1.3rem;
  font-weight: normal;
  letter-spacing: 0.01em;
  margin: 2.75rem 0 0.75rem;
}

h3 {
  font-size: 1.08rem;
  font-weight: normal;
  font-style: italic;
  color: var(--text);
  margin: 1.9rem 0 0.5rem;
}

p { margin: 0 0 1.15rem; }

hr {
  border: 0;
  border-top: 1px solid var(--rule);
  margin: 2.75rem 0;
}

/* ---------- portrait ---------- */

.portrait {
  float: right;
  width: 168px;
  height: auto;
  margin: 0.35rem 0 1.25rem 1.9rem;
  border-radius: 2px;
  filter: saturate(0.92);
}

/* ---------- interests line ---------- */

.interests {
  color: var(--muted);
  font-size: 0.97rem;
  line-height: 1.55;
}
.interests strong {
  font-weight: normal;
  font-variant: small-caps;
  letter-spacing: 0.06em;
  color: var(--text);
}

/* ---------- contact block ---------- */

.contact-lines {
  margin: 0 0 1.1rem;
  color: var(--text);
}
.contact-lines span {
  display: block;
  line-height: 1.5;
}
.contact-lines .label {
  display: inline;
  font-variant: small-caps;
  letter-spacing: 0.06em;
  color: var(--muted);
  margin-right: 0.45em;
}

.profile-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 1.5rem;
  padding-top: 1rem;
  border-top: 1px solid var(--rule);
}
.profile-links a {
  display: inline-flex;
  align-items: center;
  gap: 0.42em;
  font-variant: small-caps;
  letter-spacing: 0.06em;
  font-size: 1rem;
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}
.profile-links a:hover { border-bottom-color: var(--accent); }
.profile-links svg {
  width: 0.95em;
  height: 0.95em;
  flex: none;
  vertical-align: middle;
}

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

.news { list-style: none; margin: 0; padding: 0; }
.news li {
  margin-bottom: 0.55rem;
  padding-left: 6.2rem;
  text-indent: -6.2rem;
  line-height: 1.5;
}
.news .date {
  display: inline-block;
  width: 6.2rem;
  text-indent: 0;
  font-variant: small-caps;
  letter-spacing: 0.05em;
  color: var(--muted);
}

/* ---------- entries: papers, theses, projects, courses ---------- */

.entry { margin: 0 0 1.9rem; }
.entry .title { display: block; }
.entry .meta {
  display: block;
  color: var(--muted);
  font-size: 0.97rem;
  line-height: 1.5;
}
.entry p { margin: 0.4rem 0 0.5rem; }

.tags { font-variant: small-caps; letter-spacing: 0.06em; font-size: 0.95rem; }
.tags a { text-decoration: none; border-bottom: 1px solid var(--rule); }
.tags a:hover { border-bottom-color: var(--accent); }
.tags .sep { color: var(--muted); margin: 0 0.45em; }

code {
  font-family: "SFMono-Regular", Menlo, Consolas, monospace;
  font-size: 0.86em;
  background: color-mix(in srgb, var(--rule) 45%, transparent);
  padding: 0.08em 0.3em;
  border-radius: 2px;
}

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

.site-footer {
  margin-top: 4.5rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--rule);
  font-size: 0.92rem;
  line-height: 1.6;
  color: var(--muted);
}
.site-footer a { color: var(--muted); text-decoration: none; border-bottom: 1px solid var(--rule); }
.site-footer a:hover { color: var(--accent); border-bottom-color: var(--accent); }
.site-footer .sep { margin: 0 0.5em; }

/* ---------- narrow screens ---------- */

@media (max-width: 640px) {
  body { padding: 2.5rem 1.15rem 3rem; font-size: 17px; }

  .site-header { display: block; }
  .site-name { display: block; margin-bottom: 0.55rem; }
  .site-nav a { margin: 0 1.15rem 0 0; }

  h1 { font-size: 1.75rem; }

  .portrait {
    float: none;
    display: block;
    margin: 0 0 1.5rem;
    width: 150px;
  }

  .news li { padding-left: 0; text-indent: 0; }
  .news .date { display: block; width: auto; }
}

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

@media print {
  body { max-width: none; color: #000; background: #fff; }
  .site-nav, .profile-links { display: none; }
  a { color: #000; }
}