/* ====== Tokens ====== */
:root{
  --blue:#1555b6; --blue-ink:#0a2a5b;
  --bg:#ffffff; --fg:#101214; --muted:#5f6672; --border:#e6e8eb;
  --max:1600px; --rail-w:230px; --rside-w:280px;
}
@media (prefers-color-scheme: dark){
  :root{ --bg:#0f1115; --fg:#e7e9ee; --muted:#a7adba; --border:#273245; }
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0; background:var(--bg); color:var(--fg);
  font:16px/1.6 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,"Apple Color Emoji","Segoe UI Emoji";
}

/* ====== Shell layout: left rail | content | (optional) right sidebar ====== */
.shell{
  max-width:var(--max); margin:0 auto; padding:24px 32px;
  display:grid; grid-template-columns:var(--rail-w) 1fr var(--rside-w); gap:32px;
}
.no-right .shell{ grid-template-columns:var(--rail-w) 1fr; }
.main{display:block}

/* ====== Left rail (desktop) ====== */
.rail{position:sticky; top:24px; align-self:start}
.rail-inner{position:relative; height:calc(100vh - 48px); display:flex; flex-direction:column}
.rail .brand{padding-bottom:10px; border-bottom:1px solid var(--border); display:flex; gap:12px; align-items:center}
.rail .brand img{width:44px;height:44px;object-fit:cover}
.rail .brand.no-photo{ gap:0 }
.rail .name{margin:0;font-weight:700;font-size:1.15rem}
.rail nav{margin-top:8px}

/* Square nav items (no rounded corners) */
.rail a{
  display:flex;align-items:center;gap:10px;padding:10px 8px 10px 6px;
  text-decoration:none;color:var(--fg);border-left:4px solid transparent;border-radius:0;
}
.rail a:hover{background:#f5f7fb}
.rail a.active{border-left-color:var(--blue);background:rgba(21,85,182,.08);font-weight:700}
.btn-icon{
  display:flex;align-items:center;gap:8px;padding:10px 8px 10px 6px;
  text-decoration:none;color:var(--fg);border-left:4px solid transparent;border-radius:0;
}
.btn-icon:hover{background:#f5f7fb}
.icon{width:18px;height:18px;display:inline-block}
.rail-footer{position:absolute;left:0;right:0;bottom:0;padding-top:10px;border-top:1px solid var(--border);color:var(--muted);font-size:.9rem}

/* ====== Content ====== */
h1{margin:0 0 8px;font-size:1.9rem;font-weight:700}
p.meta{color:var(--muted);font-size:.95rem;margin:.3rem 0 1rem}
.block{margin:0 0 18px}
.grid-2{display:grid;grid-template-columns:1fr 1fr;gap:24px}
.section-title{margin:18px 0 10px;padding-bottom:6px;font-size:1.05rem;font-weight:700;color:var(--blue);border-bottom:1px solid var(--border)}
.paper{padding:12px 0}
.paper + .paper{margin-top:12px}
.paper .title{font-weight:700;font-size:1.05rem}
.paper .info{color:var(--muted);margin-top:2px}
.paper .links{display:flex;flex-wrap:wrap;gap:12px;margin:8px 0}
a.link{color:var(--blue-ink);text-decoration:none}
a.link:hover{text-decoration:underline}
.paper .intro{margin:4px 0 0}

/* ====== Right Sidebar (desktop) ====== */
.aside{position:sticky;top:24px;height:fit-content;align-self:start}
.aside h3{margin:0 0 8px;font-size:.95rem;color:var(--muted);font-weight:600}
.aside a{display:block;padding:6px 6px;color:var(--fg);text-decoration:none;border-radius:0}
.aside a:hover{background:#f5f7fb}
.aside a.active{color:var(--blue);background:rgba(21,85,182,.08)}

/* ====== Mobile / narrow ====== */
.mbar{display:none}
.backdrop{display:none}

/* Hide the floating TOC by default (desktop) */
.toc-fab, .toc-sheet{display:none}

/* ≥1200px → collapse right sidebar only */
@media (max-width:1200px){
  .shell{grid-template-columns:var(--rail-w) 1fr}
  .aside{display:none}
}

/* ≤760px → one-column layout, drawer nav, mobile TOC */
@media (max-width:760px){
  /* KEY FIX: override the more specific `.no-right .shell` so the rail column disappears */
  .shell, .no-right .shell{ grid-template-columns:1fr !important; padding:12px 16px; }

  /* top bar */
  .mbar{
    position:sticky;top:0;z-index:60;display:flex;align-items:center;gap:12px;
    background:var(--bg);border-bottom:1px solid var(--border);padding:10px 4px 10px 0;margin-bottom:10px;
  }
  .mnav-btn{
    width:40px;height:40px;border:none;background:transparent;padding:0;margin:0;cursor:pointer;
    display:inline-flex;align-items:center;justify-content:center;border-radius:8px
  }
  .mnav-btn:active{background:#f5f7fb}
  .mbar-title{margin:0;font-weight:800;font-size:1.2rem}

  /* drawer rail */
  .rail{
    position:fixed;top:0;left:0;width:86vw;max-width:360px;height:100vh;z-index:55;
    background:var(--bg);border-right:1px solid var(--border);transform:translateX(-100%);transition:transform .25s ease
  }
  .rail-inner{height:100%;padding:12px 12px 10px}
  .backdrop{position:fixed;inset:0;background:rgba(0,0,0,.25);z-index:50;display:none}
  body.menu-open .rail{transform:translateX(0)}
  body.menu-open .backdrop{display:block}

  /* 2-column helpers collapse */
  .grid-2{grid-template-columns:1fr}

  /* Floating TOC only on mobile (research/teaching) */
  .toc-fab{
    display:flex;position:fixed;right:16px;bottom:16px;z-index:40;
    width:52px;height:52px;border-radius:50%;border:1px solid var(--border);
    background:var(--bg);align-items:center;justify-content:center;box-shadow:0 2px 10px rgba(0,0,0,.12)
  }
  .toc-sheet{
    display:none;position:fixed;right:12px;bottom:84px;z-index:41;min-width:220px;
    border:1px solid var(--border);background:var(--bg);border-radius:10px
  }
  .toc-sheet a{display:block;padding:10px 12px;text-decoration:none;color:var(--fg);border-bottom:1px solid var(--border)}
  .toc-sheet a:last-child{border-bottom:none}
  body.toc-open .toc-sheet{display:block}
}

/* ====== Print ====== */
@media print{
  .rail,.aside,.mbar,.backdrop,.toc-fab,.toc-sheet{display:none!important}
  .shell{padding:0 16px;grid-template-columns:1fr}
}

/* ====== Index hero ====== */
/* Desktop: photo left, text right — FLEX (no grid) */
.hero{ display:flex; gap:32px; align-items:flex-start; }
.hero > div{ flex:1 1 auto; min-width:0 }
.portrait-wrap{ flex:0 0 380px }
.portrait{
  width:100%; max-width:380px; aspect-ratio:4/5; object-fit:cover;
  display:block; border:1px solid var(--border);
}

/* Mobile: stack — photo ABOVE text; full-width text */
@media (max-width:760px){
  .hero{ display:block !important; width:100% }
  .portrait-wrap{ display:block; margin:0 0 14px }
  .portrait{ width:100%; max-width:360px; height:auto; margin:0 auto 16px }
}

/* === Bigger portrait on wide screens === */
/* default stays 380px; scale up on larger viewports */
@media (min-width: 1100px){
  .portrait-wrap{ flex-basis: 500px !important; }  /* was 380 */
  .portrait{ max-width: 500px !important; }
}
@media (min-width: 1400px){
  .portrait-wrap{ flex-basis: 600px !important; }
  .portrait{ max-width: 600px !important; }
}

/* Language switch above footer */
.lang-switch {
  margin: 0 0 0.75rem 0;  /* spacing above footer */
}

.lang-switch a {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 0;                 
  background: none;            /* no background */
  border: none;                
  color: #666;                 /* plain gray */
  text-decoration: none;
  font-size: 0.9rem;
}

.lang-switch a:hover {
  background: none !important; /* override nav hover */
  color: #444;                 /* slightly darker on hover */
  text-decoration: underline;  /* subtle hover cue */
}

.lang-switch .icon {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

/* Reserve space for the footer so content above doesn't overlap it */
.rail-inner{ padding-bottom:56px; }           /* desktop */
@media (max-width:760px){
  .rail-inner{ padding-bottom:56px; }         /* drawer on mobile */
}

/* Language switch above the footer */
.lang-switch{
  margin-top:auto;          /* push to bottom of the flex column */
  margin-bottom:12px;       /* breathing room above the separator line */
}

.lang-switch a{
  display:inline-flex;
  align-items:center;
  gap:6px;
  padding:0;                /* not a nav pill */
  background:none !important;
  border:none;
  color:#666;               /* gray */
  text-decoration:none;
  font-size:0.9rem;
  pointer-events:auto;      /* ensure it's clickable even near footer */
}
.lang-switch a:hover{
  background:none !important;
  color:#444;
  text-decoration:underline;
}
.lang-switch .icon{ width:16px; height:16px; flex-shrink:0; }