/* =========================================================
   AI & Data Science Lab — design tokens
   ========================================================= */
:root{
  /* color */
  --paper:      #eef0f2;
  --paper-raised:#ffffff;
  --ink:        #171a21;
  --ink-soft:   #4b515c;
  --line:       #cfd4da;
  --edge:       #2f5d8a;   /* connection / link color, from network diagrams */
  --edge-soft:  #7d9ab8;
  --signal:     #b8802e;   /* single warm accent, used sparingly */
  --node-fill:  #171a21;

  /* type */
  --font-display: "Fraunces", "Iowan Old Style", "Palatino Linotype", serif;
  --font-body:    "Inter", "Helvetica Neue", Arial, sans-serif;
  --font-mono:    "IBM Plex Mono", "SFMono-Regular", Menlo, monospace;

  /* scale */
  --measure: 62ch;
  --gap: 1.5rem;
  --radius: 3px;
}

*{ box-sizing: border-box; }
html{ scroll-behavior: smooth; }

body{
  margin:0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

h1,h2,h3{
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.15;
  color: var(--ink);
  margin: 0 0 0.5em 0;
}

h1{ font-size: clamp(2.2rem, 4.5vw, 3.4rem); font-weight: 500; }
h2{ font-size: clamp(1.5rem, 2.6vw, 2rem); }
h3{ font-size: 1.15rem; }

p{ margin: 0 0 1em 0; max-width: var(--measure); color: var(--ink-soft); }

a{ color: var(--edge); text-decoration: none; }
a:hover{ text-decoration: underline; text-underline-offset: 3px; }
a:focus-visible, button:focus-visible{
  outline: 2px solid var(--signal);
  outline-offset: 3px;
}

.eyebrow{
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.02em;
  color: var(--edge);
}

.wrap{
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* ---------------------------------------------------------
   Header / nav
   --------------------------------------------------------- */
.site-header{
  border-bottom: 1px solid var(--line);
  background: var(--paper);
  position: sticky;
  top: 0;
  z-index: 20;
}

.site-header .wrap{
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 1.1rem;
  padding-bottom: 1.1rem;
}

.brand{
  display:flex;
  align-items: baseline;
  gap: 0.6rem;
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 600;
}
.brand:hover{ text-decoration: none; }
.brand .brand-mark{
  width: 10px; height: 10px;
  background: var(--signal);
  border-radius: 50%;
  display: inline-block;
  flex: none;
}
.brand small{
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 400;
  color: var(--ink-soft);
}

nav.primary-nav ul{
  list-style: none;
  display:flex;
  gap: 1.8rem;
  margin:0; padding:0;
}
nav.primary-nav a{
  color: var(--ink);
  font-size: 0.95rem;
}
nav.primary-nav a[aria-current="page"]{
  color: var(--edge);
  border-bottom: 2px solid var(--signal);
  padding-bottom: 3px;
}

.nav-toggle{
  display:none;
  background:none;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 0.4rem 0.6rem;
  font-family: var(--font-mono);
  cursor:pointer;
}

@media (max-width: 720px){
  .nav-toggle{ display:block; }
  nav.primary-nav{
    display:none;
    position:absolute;
    left:0; right:0; top: 100%;
    background: var(--paper-raised);
    border-bottom: 1px solid var(--line);
  }
  nav.primary-nav.open{ display:block; }
  nav.primary-nav ul{
    flex-direction: column;
    gap:0;
    padding: 0.5rem 2rem 1.2rem;
  }
  nav.primary-nav li{ padding: 0.55rem 0; border-bottom: 1px dashed var(--line); }
}

/* ---------------------------------------------------------
   Hero
   --------------------------------------------------------- */
.hero{
  padding: 4.5rem 0 3.5rem;
}
.hero .wrap{
  display:grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 3rem;
  align-items: center;
}
@media (max-width: 860px){
  .hero .wrap{ grid-template-columns: 1fr; }
}

.hero-copy .eyebrow{ display:block; margin-bottom: 0.9rem; }
.hero-copy p.lede{
  font-size: 1.1rem;
  color: var(--ink);
  max-width: 46ch;
}
.hero-affil{
  margin-top: 1.6rem;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--ink-soft);
  border-left: 2px solid var(--line);
  padding-left: 0.9rem;
}
.hero-affil a{ color: var(--ink-soft); }

.hero-diagram{ width: 100%; height: auto; }
.hero-diagram .edge{
  stroke: var(--edge-soft);
  stroke-width: 1;
  opacity: 0;
  animation: draw-edge 900ms ease-out forwards;
}
.hero-diagram .node{
  fill: var(--node-fill);
  opacity: 0;
  animation: pop-node 500ms ease-out forwards;
}
.hero-diagram .node.accent{ fill: var(--signal); }
.hero-diagram text{
  font-family: var(--font-mono);
  font-size: 10px;
  fill: var(--ink-soft);
}

@keyframes draw-edge{ to{ opacity: 1; } }
@keyframes pop-node{ to{ opacity: 1; } }

@media (prefers-reduced-motion: reduce){
  .hero-diagram .edge, .hero-diagram .node{
    animation: none !important;
    opacity: 1 !important;
  }
}

/* ---------------------------------------------------------
   Sections
   --------------------------------------------------------- */
section{ padding: 3.2rem 0; }
section.alt{
  background: var(--paper-raised);
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}
.section-head{
  display:flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1rem;
  margin-bottom: 2rem;
  border-bottom: 1px solid var(--line);
  padding-bottom: 0.9rem;
}
.section-head .eyebrow{ margin:0; }

/* research area grid — nodes, not cards */
.area-grid{
  display:grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 2px;
  background: var(--line);
  border: 1px solid var(--line);
}
@media (max-width: 720px){ .area-grid{ grid-template-columns: 1fr; } }

.area{
  background: var(--paper);
  padding: 1.8rem;
  position: relative;
}
.area .index{
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--edge);
  display:block;
  margin-bottom: 0.6rem;
}
.area h3{ margin-bottom: 0.5rem; }
.area p{ font-size: 0.95rem; margin-bottom: 0; }

/* news / list rows */
.row-list{ border-top: 1px solid var(--line); }
.row-item{
  display:grid;
  grid-template-columns: 9rem 1fr;
  gap: 1.5rem;
  padding: 1.1rem 0;
  border-bottom: 1px solid var(--line);
}
@media (max-width: 620px){
  .row-item{ grid-template-columns: 1fr; gap: 0.3rem; }
}
.row-item time{
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--ink-soft);
}
.row-item p{ margin:0; }

/* people grid */
.people-grid{
  display:grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}
@media (max-width: 860px){ .people-grid{ grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px){ .people-grid{ grid-template-columns: 1fr; } }

.person{ border-top: 2px solid var(--ink); padding-top: 0.9rem; }
.person .avatar{
  width: 100%;
  aspect-ratio: 1;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  margin-bottom: 0.9rem;
  display:flex;
  align-items:center;
  justify-content:center;
  font-family: var(--font-mono);
  color: var(--line);
  font-size: 0.75rem;
  overflow: hidden;
}
.person .avatar img{
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.person .avatar.initials{
  color: var(--edge);
  font-size: 1.4rem;
  font-weight: 500;
  letter-spacing: 0.03em;
  background: var(--paper);
}
.person h3{ margin-bottom: 0.15rem; }
.person .role{
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--edge);
  display:block;
  margin-bottom: 0.6rem;
}
.person p{ font-size: 0.92rem; }
.person .links a{ font-size: 0.85rem; margin-right: 0.8rem; }

/* publications */
.pub-year{
  font-family: var(--font-mono);
  color: var(--ink-soft);
  font-size: 0.85rem;
  margin: 2rem 0 0.6rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--line);
}
.pub-list{ list-style:none; margin:0; padding:0; }
.pub-item{
  padding: 1rem 0;
  border-bottom: 1px dashed var(--line);
}
.pub-item .pub-title{ color: var(--ink); font-weight: 500; }
.pub-item .pub-meta{
  display:block;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  color: var(--ink-soft);
  margin-top: 0.3rem;
}
.pub-item .pub-tag{
  display:inline-block;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  padding: 0.1rem 0.4rem;
  color: var(--ink-soft);
  margin-right: 0.4rem;
}

.placeholder-note{
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--signal);
  background: #f7ecdb;
  border: 1px dashed var(--signal);
  padding: 0.7rem 1rem;
  margin-bottom: 2rem;
  max-width: none;
}

/* ---------------------------------------------------------
   Footer
   --------------------------------------------------------- */
.site-footer{
  border-top: 1px solid var(--line);
  padding: 2.5rem 0;
  margin-top: 2rem;
}
.site-footer .wrap{
  display:flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1.5rem;
  font-size: 0.85rem;
  color: var(--ink-soft);
}
.site-footer a{ color: var(--ink-soft); }
.site-footer .cols{
  display:flex;
  gap: 3rem;
  flex-wrap: wrap;
}
.site-footer .cols div{ font-family: var(--font-mono); font-size: 0.8rem; }
.site-footer .cols a{ display:block; margin-bottom: 0.4rem; }

.btn{
  display:inline-block;
  border: 1px solid var(--ink);
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  padding: 0.55rem 1rem;
  border-radius: var(--radius);
  margin-top: 1.4rem;
}
.btn:hover{ background: var(--ink); color: var(--paper); text-decoration:none; }