/* ===========================================================
   Design tokens
=========================================================== */
:root{
  --bg:#FAF9F6;
  --bg-alt:#F2F0EA;
  --ink:#15171C;
  --muted:#5B5F68;
  --faint:#9A9DA5;
  --line:#DEDBD2;
  --indigo:#2B3A67;
  --indigo-soft:#EEF0F6;
  --gold:#B08B2E;
  --gold-soft:#F5EEDC;
  --green:#3E7A4E;
  --green-soft:#E9F1EA;

  --serif:'Fraunces', serif;
  --sans:'Inter', sans-serif;
  --mono:'IBM Plex Mono', monospace;

  --rail-w:280px;
}

*{margin:0;padding:0;box-sizing:border-box;}
html{scroll-behavior:smooth;}
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto;}
  *{animation-duration:0.01ms !important; transition-duration:0.01ms !important;}
}

body{
  background:var(--bg);
  color:var(--ink);
  font-family:var(--sans);
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
}

a{color:inherit;text-decoration:none;}
::selection{background:var(--indigo-soft);color:var(--indigo);}

/* ===========================================================
   Scroll-reveal (progressive enhancement — content is visible
   by default; only animates once JS confirms it's running)
=========================================================== */
.js-ready .reveal{
  opacity:0;
  transform:translateY(18px);
  transition:opacity .6s cubic-bezier(.16,.8,.3,1), transform .6s cubic-bezier(.16,.8,.3,1);
}
.js-ready .reveal.in-view{
  opacity:1;
  transform:translateY(0);
}
@media (prefers-reduced-motion: reduce){
  .js-ready .reveal{opacity:1;transform:none;}
}

/* ===========================================================
   Mobile header
=========================================================== */
.mobile-header{
  display:none;
  position:sticky;top:0;z-index:200;
  background:var(--bg);
  border-bottom:1px solid var(--line);
  padding:16px 24px;
  align-items:center;justify-content:space-between;
}
.mobile-name{font-family:var(--serif);font-weight:600;font-size:18px;}
.mobile-toggle{
  font-family:var(--mono);font-size:12px;letter-spacing:0.05em;text-transform:uppercase;
  background:none;border:1px solid var(--line);padding:8px 14px;border-radius:2px;cursor:pointer;color:var(--ink);
  transition:border-color .15s ease, background .15s ease;
}
.mobile-toggle:hover{border-color:var(--indigo);background:var(--indigo-soft);}

/* ===========================================================
   Page grid: rail + main
=========================================================== */
.page{
  display:grid;
  grid-template-columns:var(--rail-w) 1fr;
  max-width:1240px;
  margin:0 auto;
}

/* ---------- Left rail ---------- */
.rail{
  position:sticky;top:0;
  height:100vh;
  display:flex;flex-direction:column;justify-content:space-between;
  padding:56px 40px 40px 24px;
  border-right:1px solid var(--line);
}
.rail-name{
  font-family:var(--serif);font-weight:600;font-size:26px;line-height:1.18;
  letter-spacing:-0.01em;margin-bottom:14px;
}
.rail-role{
  font-family:var(--mono);font-size:11.5px;color:var(--muted);line-height:1.55;
  letter-spacing:0.01em;
}
.rail-nav{display:flex;flex-direction:column;gap:2px;margin:48px 0;}
.rail-nav a{
  position:relative;
  font-family:var(--sans);font-size:14.5px;color:var(--muted);
  padding:9px 0 9px 14px;display:flex;align-items:center;gap:10px;
  transition:color .15s ease;
}
.rail-nav a::before{
  content:'';position:absolute;left:0;top:50%;transform:translateY(-50%);
  width:3px;height:0;background:var(--indigo);
  transition:height .2s ease;
}
.rail-nav a:hover::before, .rail-nav a.active::before{height:60%;}
.rail-nav a .idx{
  font-family:var(--mono);font-size:11px;color:var(--faint);width:22px;
}
.rail-nav a:hover, .rail-nav a.active{color:var(--ink);}
.rail-nav a.active .idx{color:var(--indigo);}
.rail-bottom{display:flex;flex-direction:column;gap:10px;}
.rail-bottom a{
  font-family:var(--mono);font-size:12px;color:var(--muted);
  transition:color .15s ease;
}
.rail-bottom a:hover{color:var(--indigo);}

/* ===========================================================
   Main content
=========================================================== */
main{min-width:0;}

.section{
  padding:88px 56px 88px 64px;
  border-bottom:1px solid var(--line);
  position:relative;
}
.section-num{
  font-family:var(--mono);font-size:12px;color:var(--faint);
  position:absolute;left:20px;top:92px;
}
.section-title{
  font-family:var(--serif);font-weight:600;font-size:clamp(28px,3vw,38px);
  letter-spacing:-0.01em;margin-bottom:18px;
}
.section-lede{
  color:var(--muted);font-size:16px;max-width:620px;margin-bottom:48px;
}

/* ---------- Hero ---------- */
.hero-section{padding-top:64px;}
.hero-headline{
  font-family:var(--serif);font-weight:600;font-size:clamp(38px,5.2vw,68px);
  line-height:1.08;letter-spacing:-0.02em;margin-bottom:52px;max-width:820px;
  animation:rise .8s cubic-bezier(.16,.8,.3,1) both;
}
.hero-headline em{
  font-style:italic;font-weight:500;color:var(--indigo);
}
@keyframes rise{
  from{opacity:0;transform:translateY(22px);}
  to{opacity:1;transform:translateY(0);}
}
@media (prefers-reduced-motion: reduce){
  .hero-headline{animation:none;}
}
.hero-meta{
  display:grid;grid-template-columns:1.3fr 1fr;gap:56px;align-items:start;
}
.hero-intro{color:var(--muted);font-size:16.5px;max-width:440px;}
.stat-list{display:grid;grid-template-columns:1fr 1fr;gap:24px 20px;}
.stat-list div{border-top:1px solid var(--line);padding-top:10px;transition:border-color .2s ease;}
.stat-list div:hover{border-color:var(--indigo);}
.stat-list dt{
  font-family:var(--mono);font-size:10.5px;text-transform:uppercase;letter-spacing:0.06em;
  color:var(--faint);margin-bottom:6px;
}
.stat-list dd{font-family:var(--serif);font-size:20px;font-weight:600;}

@media (max-width:900px){
  .hero-meta{grid-template-columns:1fr;gap:32px;}
}

/* ---------- Project entries ---------- */
.entry-list{display:flex;flex-direction:column;}
.entry{
  padding:36px 24px 36px 20px;margin:0 -24px 0 -20px;
  border-top:1px solid var(--line);
  border-left:3px solid transparent;
  display:grid;grid-template-columns:280px 1fr;gap:32px;
  transition:border-left-color .2s ease, background .2s ease;
}
.entry:first-child{border-top:1px solid var(--line);}
.entry:hover{border-left-color:var(--indigo);background:var(--bg-alt);}
.entry-head{display:flex;align-items:center;gap:8px;flex-wrap:wrap;}
.entry-head h3{font-family:var(--serif);font-weight:600;font-size:22px;}
.badge{
  font-family:var(--mono);font-size:10px;text-transform:uppercase;letter-spacing:0.05em;
  padding:3px 9px;border-radius:2px;white-space:nowrap;
}
.badge-live{background:var(--green-soft);color:var(--green);}
.badge-repo{background:var(--bg-alt);color:var(--muted);}
.badge-featured{background:var(--indigo);color:#fff;}

.entry-desc{color:var(--muted);font-size:15px;margin:14px 0 16px;max-width:640px;}
.key-result{
  font-family:var(--mono);font-size:13px;font-weight:500;color:var(--indigo);
  background:var(--indigo-soft);border-left:2px solid var(--indigo);
  padding:10px 14px;margin:0 0 16px;max-width:640px;line-height:1.5;
}

.entry-tags{display:flex;flex-wrap:wrap;gap:7px;margin-bottom:16px;}
.entry-tags span{
  font-family:var(--mono);font-size:10.5px;color:var(--muted);
  background:var(--bg-alt);padding:4px 9px;border-radius:2px;
  transition:background .15s ease, color .15s ease;
}
.entry:hover .entry-tags span{background:#fff;}
.entry-links{display:flex;flex-direction:column;gap:8px;}
.entry-links a{
  font-family:var(--mono);font-size:12px;color:var(--indigo);
  border-bottom:1px solid transparent;width:fit-content;
  transition:border-color .15s ease;
  word-break:break-word;
}
.entry-links a:hover{border-bottom-color:var(--indigo);}

@media (max-width:760px){
  .entry{grid-template-columns:1fr;gap:8px;margin:0;padding:28px 4px 28px 16px;}
}

/* ---------- Papers (bibliography style) ---------- */
.biblio{list-style:none;}
.biblio li{
  padding:22px 20px;margin:0 -20px;
  border-top:1px solid var(--line);
  border-left:3px solid transparent;
  display:flex;flex-direction:column;gap:10px;
  transition:border-left-color .2s ease, background .2s ease;
}
.biblio li:hover{border-left-color:var(--gold);background:var(--bg-alt);}
.biblio li:last-child{border-bottom:1px solid var(--line);}
.biblio-title{
  font-family:var(--serif);font-style:italic;font-weight:500;font-size:17px;
  max-width:680px;line-height:1.4;
}
.biblio-abstract{
  font-family:var(--sans);font-size:14px;color:var(--muted);
  max-width:680px;line-height:1.55;
}
.biblio-meta{display:flex;align-items:center;gap:16px;flex-wrap:wrap;}
.biblio-id{font-family:var(--mono);font-size:11.5px;color:var(--faint);}
.biblio-status{
  font-family:var(--mono);font-size:10px;text-transform:uppercase;letter-spacing:0.05em;
  background:var(--gold-soft);color:var(--gold);padding:3px 9px;border-radius:2px;
}
.biblio-meta a{
  font-family:var(--mono);font-size:12px;color:var(--indigo);
  border-bottom:1px solid transparent;word-break:break-word;
}
.biblio-meta a:hover{border-bottom-color:var(--indigo);}

.entry-employer{
  font-family:var(--mono);font-size:12px;color:var(--faint);
  margin-top:8px;padding-top:16px;border-top:1px solid var(--line);
}

/* ---------- Skills ---------- */
.skill-grid{display:flex;flex-wrap:wrap;gap:12px;}
.skill-grid span{
  font-family:var(--mono);font-size:13px;color:var(--ink);
  border:1px solid var(--line);padding:10px 18px;border-radius:2px;
  transition:border-color .15s ease, background .15s ease, transform .15s ease;
}
.skill-grid span:hover{border-color:var(--indigo);background:var(--indigo-soft);transform:translateY(-2px);}

/* ---------- Contact ---------- */
.contact-section{border-bottom:none;}
.contact-grid{
  display:grid;grid-template-columns:1fr 1fr;gap:1px;
  background:var(--line);border:1px solid var(--line);margin-bottom:64px;max-width:680px;
}
.contact-grid a{
  background:var(--bg);padding:24px;display:flex;flex-direction:column;gap:6px;
  transition:background .15s ease;
}
.contact-grid a:hover{background:var(--indigo-soft);}
.contact-label{
  font-family:var(--mono);font-size:10.5px;text-transform:uppercase;letter-spacing:0.06em;color:var(--faint);
}
.contact-value{font-family:var(--serif);font-size:16px;font-weight:500;word-break:break-word;}

@media (max-width:600px){
  .contact-grid{grid-template-columns:1fr;}
}

.footer-bar{
  display:flex;justify-content:space-between;flex-wrap:wrap;gap:8px;
  font-family:var(--mono);font-size:11px;color:var(--faint);
  border-top:1px solid var(--line);padding-top:24px;
}

/* ===========================================================
   Chat — shared components (floating bubble + inline Ask AI section)
=========================================================== */
.chat-fab{
  position:fixed;right:24px;bottom:24px;z-index:300;
  width:56px;height:56px;border-radius:50%;
  background:var(--indigo);color:#fff;border:none;cursor:pointer;
  display:flex;align-items:center;justify-content:center;font-size:22px;
  box-shadow:0 6px 20px rgba(43,58,103,0.35);
  transition:transform .15s ease, box-shadow .15s ease;
}
.chat-fab:hover{transform:translateY(-2px);box-shadow:0 10px 26px rgba(43,58,103,0.45);}
.chat-fab.is-hidden{display:none;}

.chat-panel{
  position:fixed;right:24px;bottom:92px;z-index:300;
  width:380px;max-width:calc(100vw - 32px);
  height:520px;max-height:calc(100vh - 140px);
  background:var(--bg);border:1px solid var(--line);
  box-shadow:0 20px 60px rgba(21,23,28,0.18);
  display:flex;flex-direction:column;
  opacity:0;transform:translateY(12px) scale(.98);pointer-events:none;
  transition:opacity .18s ease, transform .18s ease;
}
.chat-panel.is-open{opacity:1;transform:translateY(0) scale(1);pointer-events:auto;}

.chat-header{
  display:flex;align-items:center;justify-content:space-between;
  padding:16px 18px;border-bottom:1px solid var(--line);flex-shrink:0;
}
.chat-header-title{font-family:var(--serif);font-weight:600;font-size:16px;}
.chat-header-sub{font-family:var(--mono);font-size:10.5px;color:var(--faint);margin-top:2px;}
.chat-close{
  background:none;border:1px solid var(--line);cursor:pointer;
  font-family:var(--mono);font-size:11px;color:var(--muted);padding:6px 12px;border-radius:2px;
  transition:border-color .15s ease,color .15s ease;
}
.chat-close:hover{border-color:var(--indigo);color:var(--indigo);}

.chat-messages{flex:1;overflow-y:auto;padding:16px 18px;display:flex;flex-direction:column;gap:12px;}
.chat-msg{max-width:88%;font-size:14px;line-height:1.55;padding:10px 13px;border-radius:2px;white-space:pre-wrap;}
.chat-msg.user{align-self:flex-end;background:var(--indigo);color:#fff;}
.chat-msg.bot{align-self:flex-start;background:var(--bg-alt);color:var(--ink);border:1px solid var(--line);}
.chat-msg.error{align-self:flex-start;background:#FBEAEA;color:#7A2E2E;border:1px solid #E8C4C4;}
.chat-msg.typing{align-self:flex-start;font-family:var(--mono);font-size:12px;color:var(--faint);background:none;border:none;padding:0 0 0 2px;}

.chat-suggestions{display:flex;flex-wrap:wrap;gap:6px;padding:0 18px 12px;flex-shrink:0;}
.chat-suggestion{
  font-family:var(--mono);font-size:11px;color:var(--indigo);
  border:1px solid var(--line);background:var(--indigo-soft);
  padding:5px 10px;border-radius:2px;cursor:pointer;transition:border-color .15s ease;
}
.chat-suggestion:hover{border-color:var(--indigo);}

.chat-input-row{display:flex;gap:8px;padding:14px 18px;border-top:1px solid var(--line);flex-shrink:0;}
.chat-input{
  flex:1;font-family:var(--sans);font-size:14px;padding:10px 12px;
  border:1px solid var(--line);border-radius:2px;background:#fff;color:var(--ink);
  resize:none;line-height:1.4;max-height:100px;
}
.chat-input:focus{outline:none;border-color:var(--indigo);}
.chat-send{
  font-family:var(--mono);font-size:12px;text-transform:uppercase;letter-spacing:.04em;
  background:var(--indigo);color:#fff;border:none;padding:0 16px;border-radius:2px;cursor:pointer;
}
.chat-send:disabled{opacity:.5;cursor:not-allowed;}
.chat-footer-note{font-family:var(--mono);font-size:10px;color:var(--faint);padding:0 18px 14px;flex-shrink:0;}

.ask-panel{
  border:1px solid var(--line);max-width:680px;
  display:flex;flex-direction:column;height:480px;
}
.ask-panel .chat-messages{padding:20px;}
.ask-panel .chat-input-row{padding:16px 20px;}
.ask-panel .chat-suggestions{padding:0 20px 12px;}

@media (max-width:600px){
  .chat-panel{right:12px;left:12px;width:auto;bottom:82px;}
  .chat-fab{right:16px;bottom:16px;}
  .ask-panel{height:440px;}
}

/* ===========================================================
   Responsive: collapse rail on mobile
=========================================================== */
@media (max-width:900px){
  .mobile-header{display:flex;}
  .page{grid-template-columns:1fr;}
  .rail{
    position:fixed;top:57px;left:0;right:0;bottom:0;height:auto;
    background:var(--bg);z-index:150;
    padding:32px 24px;
    border-right:none;border-bottom:1px solid var(--line);
    transform:translateY(-110%);
    transition:transform .25s ease;
    overflow-y:auto;
  }
  .rail.open{transform:translateY(0);}
  .rail-top{display:none;}
  .section{padding:56px 24px 56px 40px;}
  .section-num{left:8px;top:58px;}
}