/* ==========================================================================
   Structured Machine Learning Group — Design tokens
   Signature: the "structure graph" — nodes & edges as literal motif for
   "structured" machine learning (sequences, trees, graphs, relations).
   ========================================================================== */
:root{
  --bg:        #F6F5F1;   /* paper, cool neutral (not warm cream) */
  --surface:   #FFFFFF;
  --ink:       #191B22;
  --ink-soft:  #4A4E5A;
  --ink-faint: #8A8E9C;
  --accent:    #2E4374;   /* structure blue */
  --accent-2:  #1A2B4D;   /* deep blue, hover/active */
  --warm:      #D98E2B;   /* amber — used sparingly, tags/badges only */
  --line:      #DAD7CD;   /* hairline rule */
  --line-soft: #E8E6DE;
  --radius:    3px;
  --maxw:      1120px;
  --font-display: "Fraunces", "Iowan Old Style", Georgia, serif;
  --font-body:    "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --font-mono:    "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
}

*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto;}
  *{animation-duration:0.001ms !important; animation-iteration-count:1 !important; transition-duration:0.001ms !important;}
}

body{
  margin:0;
  background:var(--bg);
  color:var(--ink);
  font-family:var(--font-body);
  font-size:16px;
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
}

h1,h2,h3,h4{
  font-family:var(--font-display);
  font-weight:600;
  color:var(--ink);
  line-height:1.15;
  margin:0 0 0.5em;
}
h1{font-size:clamp(2.2rem,5vw,3.4rem); font-weight:500; letter-spacing:-0.01em;}
h2{font-size:clamp(1.5rem,3vw,2rem);}
h3{font-size:1.2rem;}
p{margin:0 0 1em;}
a{color:var(--accent); text-decoration:none;}
a:hover{text-decoration:underline;}
a:focus-visible, button:focus-visible, input:focus-visible{
  outline:2px solid var(--accent); outline-offset:2px;
}

.eyebrow{
  font-family:var(--font-mono);
  font-size:0.72rem;
  text-transform:uppercase;
  letter-spacing:0.12em;
  color:var(--accent);
  display:block;
  margin-bottom:0.6em;
}

.wrap{max-width:var(--maxw); margin:0 auto; padding:0 24px;}
.hairline{border:none; border-top:1px solid var(--line); margin:0;}
section{padding:64px 0;}
section.tight{padding:40px 0;}

/* ---------- Header / nav ---------- */
.site-header{
  position:sticky; top:0; z-index:50;
  background:rgba(246,245,241,0.92);
  backdrop-filter:saturate(180%) blur(8px);
  border-bottom:1px solid var(--line);
}
.nav{
  display:flex; align-items:center; justify-content:space-between;
  padding:16px 24px; max-width:var(--maxw); margin:0 auto;
}
.brand{
  display:flex; align-items:center; gap:10px;
  font-family:var(--font-mono); font-weight:500; font-size:0.95rem;
  color:var(--ink); text-decoration:none;
}
.brand:hover{text-decoration:none;}
.brand-logo{height:24px; width:auto; max-height:24px; object-fit:contain; display:block; flex-shrink:0;}
.brand .mark{color:var(--accent); font-size:1.1em;}
.nav-links{display:flex; gap:26px; list-style:none; margin:0; padding:0; flex-wrap:wrap;}
.nav-links a{
  color:var(--ink-soft); font-size:0.93rem; font-weight:500;
  padding:6px 0; border-bottom:2px solid transparent;
}
.nav-links a:hover, .nav-links a[aria-current="page"]{
  color:var(--ink); text-decoration:none; border-bottom-color:var(--accent);
}
.nav-toggle{display:none;}

@media (max-width:820px){
  .nav-toggle{
    display:block; background:none; border:1px solid var(--line);
    border-radius:var(--radius); padding:8px 12px; font-family:var(--font-mono);
    font-size:0.8rem; color:var(--ink); cursor:pointer;
  }
  .nav-links{
    display:none; position:absolute; top:100%; left:0; right:0;
    background:var(--surface); flex-direction:column; gap:0;
    border-bottom:1px solid var(--line); padding:8px 24px;
  }
  .nav-links.open{display:flex;}
  .nav-links a{padding:12px 0; border-bottom:1px solid var(--line-soft);}
}

/* ---------- Hero ---------- */
.hero{padding:72px 0 40px; position:relative;}
.hero-title-row{display:flex; align-items:center; gap:18px; margin-bottom:28px;}
.hero-logo{height:56px; width:auto; max-height:56px; object-fit:contain; flex-shrink:0; display:block;}
.hero-title-row h1{margin:0; max-width:none;}
.hero-grid{display:grid; grid-template-columns:1fr 1.15fr; gap:40px; align-items:center;}
@media (max-width:900px){.hero-grid{grid-template-columns:1fr;}}
.hero-lede{font-size:1.15rem; color:var(--ink-soft); max-width:52ch;}
.hero-links{display:flex; gap:16px; margin-top:32px; flex-wrap:wrap;}
.btn{
  font-family:var(--font-mono); font-size:0.85rem; letter-spacing:0.02em;
  padding:10px 18px; border-radius:var(--radius); border:1px solid var(--ink);
  color:var(--ink); display:inline-block;
}
.btn:hover{background:var(--ink); color:var(--bg); text-decoration:none;}
.btn.primary{background:var(--accent); border-color:var(--accent); color:#fff;}
.btn.primary:hover{background:var(--accent-2); border-color:var(--accent-2);}

/* graph signature */
.graph-wrap{position:relative;}
#hero-graph{width:100%; height:auto; display:block;}
.node{fill:var(--surface); stroke:var(--accent); stroke-width:1.6;}
.node-label{
  font-family:var(--font-mono); font-size:13px; fill:var(--ink-soft);
}
.edge{stroke:var(--line); stroke-width:1; }
.edge.pulse{stroke:var(--accent); opacity:0.55;}

/* ---------- Section headers ---------- */
.section-head{display:flex; align-items:baseline; justify-content:space-between; gap:24px; margin-bottom:28px; flex-wrap:wrap;}
.section-head h2{margin:0;}
.section-head .more{font-family:var(--font-mono); font-size:0.82rem;}

/* ---------- Cards ---------- */
.card-grid{display:grid; grid-template-columns:repeat(auto-fill,minmax(260px,1fr)); gap:20px;}
.card{
  background:var(--surface); border:1px solid var(--line); border-radius:var(--radius);
  padding:24px; display:flex; flex-direction:column; gap:10px;
}
.card h3{margin-bottom:2px;}
.card .tag{
  font-family:var(--font-mono); font-size:0.7rem; text-transform:uppercase;
  letter-spacing:0.08em; color:var(--warm); align-self:flex-start;
  border:1px solid var(--warm); border-radius:20px; padding:2px 10px;
}
.card p{color:var(--ink-soft); font-size:0.94rem; margin-bottom:0;}
.card .card-links{margin-top:auto; display:flex; gap:14px; font-family:var(--font-mono); font-size:0.8rem;}

/* ---------- Publications ---------- */
.pub-controls{
  display:flex; gap:12px; flex-wrap:wrap; margin-bottom:24px;
  font-family:var(--font-mono); font-size:0.85rem;
}
.pub-controls input[type="search"]{
  flex:1; min-width:200px; padding:10px 12px; border:1px solid var(--line);
  border-radius:var(--radius); background:var(--surface); font-family:var(--font-body); font-size:0.95rem;
}
.pub-controls select{
  padding:10px 12px; border:1px solid var(--line); border-radius:var(--radius);
  background:var(--surface); font-family:var(--font-mono); font-size:0.85rem;
}
.pub-list{list-style:none; margin:0; padding:0;}
.pub-item{
  padding:20px 0; border-top:1px solid var(--line-soft);
  display:grid; grid-template-columns:64px 1fr; gap:18px;
}
.pub-item:first-child{border-top:none;}
.pub-year{font-family:var(--font-mono); color:var(--ink-faint); font-size:0.95rem; padding-top:2px;}
.pub-title{font-weight:600; margin-bottom:4px;}
.pub-authors{color:var(--ink-soft); font-size:0.92rem; margin-bottom:2px;}
.pub-venue{color:var(--ink-faint); font-size:0.88rem; font-style:italic; margin-bottom:6px;}
.pub-links{font-family:var(--font-mono); font-size:0.8rem; display:flex; gap:14px;}
.pub-status{font-family:var(--font-mono); font-size:0.8rem; color:var(--ink-faint); text-align:center; padding:20px 0;}

/* ---------- Social / news ---------- */
.social-grid{display:grid; grid-template-columns:1fr 1fr; gap:28px;}
@media (max-width:760px){.social-grid{grid-template-columns:1fr;}}
.social-col h3{
  font-family:var(--font-mono); font-size:0.85rem; text-transform:uppercase;
  letter-spacing:0.08em; color:var(--ink-soft); border-bottom:1px solid var(--line); padding-bottom:10px;
}
.post-list{list-style:none; margin:0; padding:0; display:flex; flex-direction:column; gap:14px;}
.post{
  border:1px solid var(--line); border-radius:var(--radius); padding:14px 16px;
  background:var(--surface); font-size:0.92rem;
}
.post-meta{font-family:var(--font-mono); font-size:0.72rem; color:var(--ink-faint); margin-bottom:6px; display:flex; justify-content:space-between;}
.post a{word-break:break-word;}
.social-status{font-family:var(--font-mono); font-size:0.8rem; color:var(--ink-faint);}

/* ---------- Footer ---------- */
.site-footer{
  border-top:1px solid var(--line); padding:36px 0; margin-top:40px;
  font-family:var(--font-mono); font-size:0.82rem; color:var(--ink-faint);
}
.site-footer .wrap{display:flex; justify-content:space-between; flex-wrap:wrap; gap:12px;}
.site-footer a{color:var(--ink-soft);}

/* ---------- Generic content pages ---------- */
.page-head{padding:56px 0 24px;}
.page-head .eyebrow{margin-bottom:10px;}
.prose{max-width:70ch;}
.prose p{color:var(--ink-soft);}
ul.plain{padding-left:1.1em;}
ul.plain li{margin-bottom:6px; color:var(--ink-soft);}

/* ---------- Course pages (Teaching) ---------- */
.course-badges{display:flex; gap:10px; flex-wrap:wrap; margin-bottom:6px;}
.course-badges .tag{position:static;}
.course-meta{list-style:none; margin:0 0 28px; padding:0; border-top:1px solid var(--line);}
.course-meta li{
  display:grid; grid-template-columns:160px 1fr; gap:16px;
  padding:14px 0; border-bottom:1px solid var(--line-soft);
}
.course-meta .k{
  font-family:var(--font-mono); font-size:0.78rem; text-transform:uppercase;
  letter-spacing:0.06em; color:var(--ink-faint); padding-top:2px;
}
.course-meta .v{color:var(--ink-soft);}
.course-meta .v a{word-break:break-word;}
.material-list{list-style:none; margin:0; padding:0;}
.material-list li{
  padding:10px 0; border-top:1px solid var(--line-soft);
  display:flex; justify-content:space-between; align-items:baseline; gap:16px; flex-wrap:wrap;
}
.material-list li:first-child{border-top:none;}
.material-list .m-name{color:var(--ink);}
.material-list .m-links{font-family:var(--font-mono); font-size:0.8rem; display:flex; gap:12px;}
.year-switch{
  font-family:var(--font-mono); font-size:0.82rem; color:var(--ink-faint);
  margin-bottom:20px;
}
.year-switch a{color:var(--ink-soft);}