/* ==========================================================================
   Ying Ding Lab — shared stylesheet
   Classical academic elegance with a warm, luxe register:
   "high-priced wood" — walnut/espresso browns on a soft warm-beige ground.
   Restrained on purpose. Edit palette below.
   ========================================================================== */

:root {
  /* Color palette (warm "wood + skin", AA-checked) */
  --bg:            #F5ECDE;  /* warm light beige page background */
  --bg-panel:      #EDE0CE;  /* soft warm sand: footer, callouts, headshot */
  --text:          #2A2119;  /* primary text, dark espresso */
  --text-muted:    #6F5D4A;  /* secondary text, warm taupe */
  --accent:        #5A3E2B;  /* walnut brown: headings, links, rules */
  --accent-dark:   #3E2A1C;  /* hover / pressed */
  --hairline:      #DFD0BC;  /* borders, dividers */
  --pitt-blue:     #003594;  /* University of Pittsburgh official blue */

  /* Type */
  --font-head: "Cormorant Garamond", Georgia, "Times New Roman", serif;
  --font-body: "Source Serif 4", Georgia, "Times New Roman", serif;

  /* Measure & rhythm */
  --wrap:  66rem;   /* header / footer width */
  --prose: 60rem;   /* reading measure (wide, per request for narrow margins) */
  --pad:   1rem;
}

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

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 1.125rem;      /* 18px */
  line-height: 1.65;
  font-weight: 400;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }

/* -------------------------------------------------------------- Skip link */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--accent);
  color: #fff;
  padding: 0.5rem 1rem;
  z-index: 100;
  text-decoration: none;
}
.skip-link:focus {
  left: 0.75rem;
  top: 0.75rem;
}

/* --------------------------------------------------------------- Wrappers */
.wrap {
  width: 100%;
  max-width: var(--wrap);
  margin-inline: auto;
  padding-inline: var(--pad);
}

/* ---------------------------------------------------------------- Header */
.site-header {
  border-bottom: 1px solid var(--hairline);
  padding-block: 2.1rem 0;
}
/* One masthead row: institution badge on the left, primary nav to its right. */
.site-header-inner {
  display: flex;
  align-items: flex-end;
  gap: 0.75rem 2rem;
  flex-wrap: wrap;
}
.site-badge-link {
  display: inline-flex;
  flex: 0 0 auto;
  text-decoration: none;
}
.site-badge {
  height: 46px;
  width: auto;
  display: block;
}

/* Navigation */
.main-nav {
  margin: 0;
}
.main-nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.4rem;
}
.main-nav a {
  display: inline-block;
  padding: 0.35rem 0;
  font-size: 0.98rem;
  letter-spacing: 0.02em;
  color: var(--text-muted);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  transition: color 120ms ease, border-color 120ms ease;
}
.main-nav a:hover,
.main-nav a:focus-visible {
  color: var(--accent);
  border-bottom-color: var(--hairline);
}
.main-nav a[aria-current="page"] {
  color: var(--accent);
  font-weight: 600;
  border-bottom-color: var(--accent);
}

/* ------------------------------------------------------------------ Main */
main {
  max-width: var(--prose);
  margin-inline: auto;
  padding: 3rem var(--pad) 4rem;
}

/* Page header block */
.page-header { margin-bottom: 2.5rem; }
.page-title {
  font-family: var(--font-head);
  font-weight: 600;
  font-size: clamp(2.2rem, 5vw, 3rem);
  line-height: 1.08;
  letter-spacing: 0.005em;
  color: var(--accent);
  margin: 0;
}
.page-header .rule {
  width: 3.5rem;
  height: 2px;
  background: var(--accent);
  border: 0;
  margin: 1.1rem 0 0;
}

/* Lead paragraph — used on the warmer pages */
.lead {
  font-size: 1.3rem;
  line-height: 1.55;
  color: var(--text);
  margin: 1.4rem 0 1.9rem;   /* bottom margin gives a clear break before the next paragraph */
}
.lead-italic {
  font-family: var(--font-head);
  font-size: 1.5rem;
  font-style: italic;
  color: var(--accent);
  line-height: 1.4;
  margin: 1rem 0 0;
}

/* ----------------------------------------------------------- Typography */
h2 {
  font-family: var(--font-head);
  font-weight: 600;
  font-size: 1.75rem;
  line-height: 1.15;
  color: var(--accent);
  margin: 2.75rem 0 1rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--hairline);
}
h3 {
  font-family: var(--font-head);
  font-weight: 600;
  font-size: 1.35rem;
  line-height: 1.2;
  color: var(--text);
  margin: 2rem 0 0.5rem;
}
p { margin: 0 0 1.15rem; }
main > section > p:last-child { margin-bottom: 0; }

a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 0.14em;
  text-decoration-thickness: 1px;
  text-decoration-color: var(--hairline);
  transition: color 120ms ease, text-decoration-color 120ms ease;
}
a:hover,
a:focus-visible {
  color: var(--accent-dark);
  text-decoration-color: currentColor;
}

strong { font-weight: 600; }
em { font-style: italic; }

hr.divider {
  border: 0;
  border-top: 1px solid var(--hairline);
  margin: 2.5rem 0;
}

/* --------------------------------------------------- CV-style definition lists */
/* Education, appointments, courses: label + detail rows */
.cv-list {
  margin: 1.25rem 0 0;
  display: grid;
  gap: 1.4rem;
}
.cv-item {
  display: grid;
  grid-template-columns: 7.5rem 1fr;
  gap: 0.25rem 1.5rem;
}
.cv-item .cv-when {
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
  font-size: 0.98rem;
  padding-top: 0.1rem;
}
.cv-item .cv-what { margin: 0; }
.cv-item .cv-what .cv-role { font-weight: 600; }
.cv-item .cv-what .cv-where { color: var(--text-muted); display: block; font-size: 0.98rem; }

/* Simple stacked list (awards, plain items) */
.stack-list {
  margin: 1.25rem 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 0.9rem;
}
.stack-list li {
  display: grid;
  grid-template-columns: 4rem 1fr;
  gap: 1.25rem;
}
.stack-list .yr {
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
  font-size: 0.98rem;
}

/* -------------------------------------------------------- Research interests */
/* Home page: each interest = title + description + a line of recent citations. */
.interests {
  margin: 1.5rem 0 0;
  display: grid;
  gap: 2.25rem;
}
.interest .i-title {
  font-family: var(--font-head);
  font-weight: 600;
  font-size: 1.35rem;
  line-height: 1.2;
  color: var(--accent);
  margin: 0 0 0.45rem;
}
.interest .i-desc { margin: 0 0 0.6rem; }
.interest .i-pubs {
  margin: 0;
  padding-left: 1.1rem;
  border-left: 2px solid var(--hairline);
  font-size: 0.95rem;
  line-height: 1.6;
  color: var(--text-muted);
}
.interest .i-pubs-label {
  display: block;
  font-family: var(--font-head);
  font-style: italic;
  font-size: 1.05rem;
  color: var(--accent);
}
.i-more { margin-top: 2.25rem; font-size: 0.95rem; }

/* --------------------------------------------------------------- News list */
.news {
  margin: 1.25rem 0 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 1rem;
}
.news li {
  display: grid;
  grid-template-columns: 6rem 1fr;
  gap: 1.25rem;
}
.news .news-date {
  color: var(--text-muted);
  font-size: 0.92rem;
  font-variant-numeric: tabular-nums;
  padding-top: 0.05rem;
}
.news p { margin: 0; }

/* -------------------------------------------------------------- Publications */
.pub-year {
  font-family: var(--font-head);
  font-weight: 600;
  font-size: 1.75rem;
  color: var(--accent);
  margin: 2.75rem 0 1rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--hairline);
}
.pub-list {
  margin: 0;
  padding: 0;
  list-style: none;
  display: grid;
  gap: 1.4rem;
}
.pub-list li { padding-left: 1.1rem; border-left: 2px solid var(--hairline); }
.pub-list .pub-title { font-weight: 600; }
.pub-list .pub-venue { font-style: italic; color: var(--text-muted); }
.pub-list .pub-meta { display: block; margin-top: 0.2rem; font-size: 0.95rem; }

/* --------------------------------------------------------------- People */
.people-group { margin-top: 1rem; }
.person {
  display: grid;
  grid-template-columns: 12.5rem 1fr;
  gap: 0.15rem 1.75rem;
  padding: 0.7rem 0;
  border-bottom: 1px solid var(--hairline);
}
.person:last-child { border-bottom: 0; }
.person .p-name { font-weight: 600; }
.person .p-role { color: var(--text-muted); }

/* PI card — a little warmth on the People page */
.pi-card {
  display: grid;
  grid-template-columns: 9.5rem 1fr;
  gap: 1.75rem;
  align-items: start;
  margin-top: 1.5rem;
}
.pi-card .headshot {
  width: 9.5rem;
  border: 1px solid var(--hairline);
  background: var(--bg-panel);
}
.pi-card h3 { margin-top: 0; }
.pi-card .p-role { color: var(--text-muted); margin-top: -0.25rem; }

/* --------------------------------------------------------------- Callout */
/* Warm note — prospective students, contact aside */
.callout {
  background: var(--bg-panel);
  border-left: 3px solid var(--accent);
  padding: 1.25rem 1.5rem;
  margin: 2rem 0 0;
}
.callout p:last-child { margin-bottom: 0; }
.callout h2,
.callout h3 { border: 0; margin-top: 0; }
.callout .eeo { font-size: 0.88rem; color: var(--text-muted); margin-top: 0.75rem; }

/* Highlighted callout — used for the open postdoc position, so it reads clearly
   as a live announcement rather than ordinary body copy. */
.callout-open {
  border-left-width: 5px;
  padding: 1.6rem 1.75rem;
}
.callout-open h3 {
  font-size: 1.7rem;
  color: var(--accent);
  margin-bottom: 0.2rem;
}
.callout-open .open-tag {
  display: inline-block;
  margin-bottom: 0.55rem;
  font-family: var(--font-body);
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--accent);
}
.callout-open .open-lead {
  font-size: 1.1rem;
  font-weight: 600;
}

/* Contact details block */
.contact-list {
  margin: 1.5rem 0 0;
  display: grid;
  gap: 1.1rem;
}
.contact-list .c-row { display: grid; grid-template-columns: 7rem 1fr; gap: 1.25rem; }
.contact-list .c-label {
  color: var(--text-muted);
  font-size: 0.98rem;
  letter-spacing: 0.02em;
}
.contact-list .c-value { margin: 0; }

/* ---------------------------------------------------------------- Footer */
.site-footer {
  background: var(--bg-panel);
  border-top: 1px solid var(--hairline);
  color: var(--text-muted);
  padding-block: 2rem;
  font-size: 0.92rem;
}
.site-footer .foot-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.75rem 2rem;
}
.site-footer p { margin: 0; }
.site-footer a { color: var(--accent); }
.site-footer nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.1rem;
}
.site-footer nav a { text-decoration: none; }
.site-footer nav a:hover { text-decoration: underline; }
/* Deliberately understated: its own line at the very bottom, small and faint. */
.site-footer .last-updated {
  flex-basis: 100%;
  margin-top: 0.9rem;
  font-size: 0.8rem;
  opacity: 0.7;
}

/* ---------------------------------------------------------------- Hero (home) */
.hero {
  position: relative;
  background-color: var(--accent-dark);
  background-image: url("../img/pittsburgh.jpg");   /* swap this file to change the hero photo */
  background-size: cover;
  background-position: center;
  border-bottom: 1px solid var(--hairline);
}
.hero::before {
  /* solid warm wash (not a gradient) to keep overlaid text legible;
     deepen the alpha if you swap in a bright photo */
  content: "";
  position: absolute;
  inset: 0;
  background: rgba(42, 33, 25, 0.45);
}
.hero-inner {
  position: relative;
  max-width: var(--wrap);
  margin-inline: auto;
  padding: clamp(3.25rem, 11vw, 6.5rem) var(--pad);
  color: #F5ECDE;
}
.hero-title {
  font-family: var(--font-head);
  font-weight: 600;
  font-size: clamp(3rem, 10vw, 5.5rem);
  line-height: 1;
  letter-spacing: 0.01em;
  margin: 0;
  color: #F5ECDE;
}

/* ".pitt" spans are kept in the markup but no longer coloured — "University of
   Pittsburgh" now reads in the same colour as surrounding text. */
.pitt { color: inherit; }

/* -------------------------------------------- Affiliation inside the hero (home) */
/* Department + street address, directly under the "Ding Lab" hero title. */
.hero .affiliation-text { margin-top: 1rem; }
.hero .affiliation-text p { margin: 0; }
.hero .aff-dept { color: #F5ECDE; font-weight: 600; font-size: 1.15rem; }
.hero .aff-addr { color: #EDE0CE; font-size: 0.95rem; margin-top: 0.25rem; }

/* ------------------------------------------------- Full-bleed page banner (16:9) */
/* Used on teaching.html. Sits between the header and <main>, edge to edge. */
.page-banner {
  margin: 0;
  width: 100%;
  background: var(--bg-panel);
  border-bottom: 1px solid var(--hairline);
}
.page-banner img {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  object-fit: cover;   /* a non-16:9 photo is centre-cropped rather than squashed */
  object-position: center;
}

/* -------------------------------------------------------------- Research figure */
figure.research-figure { margin: 1.5rem 0 0; }
figure.research-figure img {
  width: 100%;
  border: 1px solid var(--hairline);
  background: var(--bg-panel);
}
figure.research-figure figcaption {
  margin-top: 0.5rem;
  font-size: 0.92rem;
  color: var(--text-muted);
}

/* --------------------------------------------------------- People photo grid */
.people-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 2rem 1.5rem;
  margin-top: 1.5rem;
}
.member-card { margin: 0; }
.member-card .avatar {
  width: 100%;
  max-width: 160px;
  aspect-ratio: 1 / 1;
  object-fit: cover;
  object-position: center 20%;  /* bias toward faces; no effect on already-square photos */
  border-radius: 50%;
  border: 1px solid var(--hairline);
  background: var(--bg-panel);
}
.member-card figcaption { margin-top: 0.75rem; }
.member-card .m-name { font-weight: 600; margin: 0; }
.member-card .m-role { color: var(--text-muted); font-size: 0.95rem; margin: 0.1rem 0 0; }

/* ------------------------------------------------------------ Focus states */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* --------------------------------------------------------------- Responsive */
@media (max-width: 34rem) {
  body { font-size: 1.06rem; }
  main { padding-top: 2.25rem; }
  .cv-item { grid-template-columns: 1fr; gap: 0.15rem; }
  .stack-list li { grid-template-columns: 3.25rem 1fr; gap: 0.85rem; }
  .news li { grid-template-columns: 1fr; gap: 0.15rem; }
  .contact-list .c-row { grid-template-columns: 1fr; gap: 0.1rem; }
  .pi-card { grid-template-columns: 1fr; gap: 1rem; }
  .pi-card .headshot { width: 8rem; }
  .lead { font-size: 1.2rem; }
  .people-grid { grid-template-columns: repeat(auto-fill, minmax(120px, 1fr)); gap: 1.5rem 1.25rem; }
  .member-card .avatar { max-width: 130px; }
  .person { grid-template-columns: 1fr; gap: 0.1rem; }
  .site-badge { height: 40px; }
}