:root {
  --bg:#f7f8fa; --surface:#ffffff; --surface-2:#f0f3f6; --text:#1f2328; --muted:#57606a;
  --border:#d8dee4; --border-strong:#c6ccd4; --accent:#0b5cad; --accent-2:#0969da;
  --ok:#1a7f37; --ok-bg:#e8f5ec; --warn:#9a6700; --warn-bg:#fff8e1; --err:#b42318; --err-bg:#fdecea;
  --code-bg:#f6f8fa; --shadow:0 1px 2px rgba(27,31,36,.06), 0 3px 12px rgba(27,31,36,.05);
}
* { box-sizing:border-box; }
html { -webkit-text-size-adjust:100%; }
body { margin:0; background:var(--bg); color:var(--text);
  font:16px/1.62 -apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif; }

/* masthead: the logo sits on its own row, at content width */
.masthead { background:var(--surface); border-bottom:1px solid var(--border); }
.masthead .wrap, nav.mainnav .wrap { max-width:1080px; margin:0 auto; padding:.75rem 1rem; }
.masthead .brand { display:block; text-decoration:none; }
.masthead .logo { display:block; width:100%; height:auto; border-radius:12px; }
nav.mainnav { position:sticky; top:0; z-index:20; background:rgba(255,255,255,.94);
  backdrop-filter:saturate(140%) blur(8px); border-bottom:1px solid var(--border); }
nav.mainnav .wrap { padding:.5rem 1rem; display:flex; align-items:center; gap:1rem; flex-wrap:wrap; }
nav.mainnav .links { display:flex; gap:.9rem; flex-wrap:wrap; }
nav.mainnav a { color:var(--muted); text-decoration:none; font-size:.9rem; padding:.15rem 0;
  border-bottom:2px solid transparent; }
nav.mainnav a:hover { color:var(--accent); border-bottom-color:var(--accent); }

main { max-width:1080px; margin:0 auto; padding:1.2rem 1rem 3rem; }
main.narrow { max-width:980px; }
h1,h2,h3,h4 { line-height:1.25; margin:1.5em 0 .55em; }
h1 { font-size:1.7rem; }
h2 { font-size:1.25rem; margin-top:2.2rem; padding-bottom:.25rem; border-bottom:1px solid var(--border); }
h3 { font-size:1.05rem; }
a { color:var(--accent-2); }
a:hover { color:var(--accent); }
p { margin:.65rem 0; }
code { font-family:ui-monospace,SFMono-Regular,"SF Mono",Menlo,Consolas,monospace; font-size:.87em;
  background:var(--code-bg); border:1px solid var(--border); border-radius:5px; padding:.08em .35em; }
pre { position:relative; background:var(--code-bg); border:1px solid var(--border); border-radius:8px;
  padding:.85rem 1rem; overflow:auto; }
pre code { background:none; border:0; padding:0; font-size:.85rem; }
pre .copy { position:absolute; top:.45rem; right:.45rem; font-size:.72rem; padding:.15rem .45rem;
  border:1px solid var(--border-strong); border-radius:5px; background:var(--surface); color:var(--muted);
  cursor:pointer; opacity:0; transition:opacity .12s; }
pre:hover .copy { opacity:1; }
table { border-collapse:collapse; width:100%; margin:1rem 0; font-size:.9rem; display:block; overflow:auto;
  background:var(--surface); border:1px solid var(--border); border-radius:8px; }
th,td { border:1px solid var(--border); padding:.45rem .6rem; text-align:left; vertical-align:top; }
th { background:var(--surface-2); font-weight:600; }
blockquote { margin:1rem 0; padding:.55rem 1rem; border-left:3px solid var(--accent-2);
  background:var(--surface); color:#3b434d; border-radius:0 8px 8px 0; }
hr { border:0; border-top:1px solid var(--border); margin:2rem 0; }
ul,ol { padding-left:1.4rem; }
li { margin:.2rem 0; }
img { max-width:100%; }
.muted { color:var(--muted); }
.toc { background:var(--surface); border:1px solid var(--border); border-radius:10px; padding:.6rem .9rem;
  margin:1rem 0 1.4rem; box-shadow:var(--shadow); font-size:.9rem; }
.toc .toc-title { font-size:.72rem; text-transform:uppercase; letter-spacing:.08em; color:var(--muted);
  font-weight:700; margin-bottom:.2rem; }
.toc ul { margin:.2rem 0; padding-left:1.1rem; }
.toc a { color:var(--muted); text-decoration:none; }
.toc a:hover { color:var(--accent); }
.small { font-size:.86rem; }

/* hero */
.hero { background:linear-gradient(180deg,#eef5ff 0%,#f7f8fa 100%); border:1px solid var(--border);
  border-radius:14px; padding:1.6rem 1.5rem 1.4rem; box-shadow:var(--shadow); margin:.4rem 0 1.6rem; }
.kicker { text-transform:uppercase; letter-spacing:.08em; font-size:.74rem; color:var(--accent); font-weight:700; }
.hero h1 { font-size:2rem; margin:.4rem 0 .5rem; }
.hero h1 em { color:var(--accent); font-style:normal; }
.lede { font-size:1.03rem; color:#333b44; max-width:62ch; }
.cta { display:flex; gap:.6rem; flex-wrap:wrap; margin-top:.9rem; }
.btn { display:inline-block; padding:.5rem .9rem; border-radius:8px; border:1px solid var(--border-strong);
  background:var(--surface); color:var(--text); text-decoration:none; font-size:.92rem; font-weight:600;
  box-shadow:var(--shadow); }
.btn:hover { border-color:var(--accent-2); color:var(--accent); }
.btn-primary { background:var(--accent); border-color:var(--accent); color:#fff; }
.btn-primary:hover { background:#0a4f96; color:#fff; }
.badges { margin:.7rem 0 0; display:flex; gap:.4rem; flex-wrap:wrap; }
.badge { display:inline-block; padding:.18rem .55rem; border-radius:999px; font-size:.76rem; font-weight:700;
  letter-spacing:.02em; background:var(--surface-2); color:var(--muted); border:1px solid var(--border); }
.badge-ok { background:var(--ok-bg); color:var(--ok); border-color:#b7e0c4; }
.badge-warn { background:var(--warn-bg); color:var(--warn); border-color:#ecd9a3; }
.badge-user { background:#e8f0fe; color:#0b5cad; border-color:#c3d7f7; }
.badge-ai { background:#eef0ff; color:#4a3fbf; border-color:#d3d0f7; }

/* stats + cards */
.stats { display:grid; grid-template-columns:repeat(auto-fit,minmax(190px,1fr)); gap:.8rem; margin:1rem 0 1.8rem; }
.stat { background:var(--surface); border:1px solid var(--border); border-radius:12px; padding:.9rem 1rem;
  box-shadow:var(--shadow); text-align:center; }
.stat-value { font-size:1.6rem; font-weight:800; color:var(--accent); }
.stat-label { font-size:.84rem; color:var(--muted); margin-top:.2rem; }
.cards { display:grid; grid-template-columns:repeat(auto-fit,minmax(240px,1fr)); gap:.8rem; }
.card { background:var(--surface); border:1px solid var(--border); border-radius:12px; padding:1rem 1.1rem;
  box-shadow:var(--shadow); }
.card h3 { margin-top:0; }
.card p { color:#3b434d; font-size:.94rem; }

/* media + gallery */
.media video { width:100%; height:auto; border:1px solid var(--border-strong); border-radius:12px;
  box-shadow:var(--shadow); background:#000; }
.gallery { display:grid; grid-template-columns:repeat(auto-fit,minmax(280px,1fr)); gap:.9rem; }
.gallery figure { margin:0; background:var(--surface); border:1px solid var(--border); border-radius:12px;
  padding:.5rem; box-shadow:var(--shadow); }
.gallery img { border-radius:8px; border:1px solid var(--border); display:block; }
.gallery figcaption { font-size:.84rem; color:var(--muted); padding:.45rem .2rem 0; }

/* session transcript */
.session-summary { background:var(--surface); border:1px solid var(--border); border-radius:12px;
  padding:1.1rem 1.2rem; box-shadow:var(--shadow); margin-bottom:1.4rem; }
.session-summary h1 { margin:.1rem 0 .4rem; font-size:1.5rem; }
.stat-grid { display:grid; grid-template-columns:repeat(auto-fit,minmax(120px,1fr)); gap:.6rem; margin:.8rem 0; }
.stat-grid .stat-value { font-size:1.25rem; }
.toolbar { display:flex; gap:.5rem; flex-wrap:wrap; align-items:center; margin:.8rem 0 .2rem; }
.toolbar input[type=search] { flex:1 1 240px; padding:.45rem .6rem; border:1px solid var(--border-strong);
  border-radius:8px; background:var(--surface); font-size:.92rem; }
.toolbar button { padding:.42rem .7rem; border:1px solid var(--border-strong); border-radius:8px;
  background:var(--surface); cursor:pointer; font-size:.86rem; color:var(--muted); }
.toolbar button:hover { border-color:var(--accent-2); color:var(--accent); }
.turn { margin:1.4rem 0; }
.turn-head { font-size:.95rem; text-transform:uppercase; letter-spacing:.06em; color:var(--muted);
  border-bottom:1px solid var(--border); padding-bottom:.3rem; }
.turn-end { font-size:.8rem; margin:.2rem 0 0; }
.ev { margin:.7rem 0; }
.ev-head { display:flex; gap:.5rem; align-items:center; font-size:.8rem; margin-bottom:.25rem; }
.bubble { background:var(--surface); border:1px solid var(--border); border-radius:10px; padding:.2rem .9rem;
  box-shadow:var(--shadow); }
.ev-user .bubble { background:#f4f8ff; border-color:#d6e4fb; }
.ev-assistant > .md, .ev-assistant > details { background:var(--surface); border:1px solid var(--border);
  border-radius:10px; padding:.2rem .9rem; margin:.35rem 0; box-shadow:var(--shadow); }
.reasoning, .tool, .system-ctx { background:var(--surface); border:1px solid var(--border); border-radius:10px;
  padding:.45rem .8rem; margin:.35rem 0; box-shadow:var(--shadow); }
.reasoning summary, .tool summary, .system-ctx summary { cursor:pointer; color:var(--muted); font-size:.86rem; }
.reasoning[open], .tool[open], .system-ctx[open] { padding-bottom:.6rem; }
.tool summary { display:flex; gap:.5rem; align-items:center; }
.tool-name { font-weight:700; color:var(--accent); font-size:.84rem; }
.tool-desc { color:var(--muted); font-size:.84rem; flex:1; overflow:hidden; text-overflow:ellipsis;
  white-space:nowrap; }
.tool-status { font-size:.72rem; font-weight:700; padding:.05rem .45rem; border-radius:999px; }
.tool-status.ok { background:var(--ok-bg); color:var(--ok); }
.tool-status.err { background:var(--err-bg); color:var(--err); }
.tool-body pre { margin:.4rem 0; }
.tool-result-label { font-size:.74rem; text-transform:uppercase; letter-spacing:.06em;
  color:var(--muted); margin-top:.5rem; }
.note { border-left:3px solid var(--accent-2); background:var(--surface); border-radius:0 8px 8px 0;
  padding:.5rem .9rem; margin:.8rem 0; box-shadow:var(--shadow); }
.goal-note { border-left-color:var(--warn); }
.pre-wrap { white-space:pre-wrap; word-break:break-word; }
.md pre { background:var(--code-bg); }

footer { max-width:1080px; margin:0 auto; padding:1.1rem 1rem 2rem; color:var(--muted);
  font-size:.82rem; border-top:1px solid var(--border); }
footer p { margin:.3rem 0; }
footer code { font-size:.95em; }

@media (max-width:640px) {
  .hero h1 { font-size:1.55rem; }
  main { padding:.9rem .7rem 2rem; }
  nav.mainnav .wrap { padding:.5rem .7rem; }
}
/* credits */
.credit { font-size:.8rem; color:var(--muted); }
nav.mainnav .credit { margin-left:auto; white-space:nowrap; }
nav.mainnav .credit a, footer .credit a { color:var(--accent-2); }
.credits-top, .credits-bottom { color:var(--muted); font-size:.86rem; }
.credits-bottom { margin-top:2rem; border-top:1px solid var(--border); padding-top:.8rem; }

/* mobile polish */
@media (max-width:760px) {
  body { font-size:15.5px; }
  nav.mainnav .wrap { gap:.45rem; padding:.5rem .7rem; }
  nav.mainnav .links { gap:.55rem .85rem; }
  nav.mainnav a { font-size:.85rem; }
  nav.mainnav .credit { flex-basis:100%; order:3; font-size:.74rem; }
  main { padding:1rem .75rem 2.4rem; }
  .hero { padding:1.15rem .95rem 1rem; }
  .hero h1 { font-size:1.5rem; }
  .lede { font-size:.98rem; }
  .cards, .gallery, .stats { grid-template-columns:1fr; }
  .stat { padding:.75rem .9rem; }
  .toolbar input[type=search] { flex:1 1 100%; }
  .tool summary { flex-wrap:wrap; row-gap:.2rem; }
  .tool-desc { white-space:normal; }
  .bubble, .ev-assistant > .md, .ev-assistant > details { padding:.15rem .7rem; }
  .session-summary { padding:.9rem; }
  table { font-size:.84rem; }
  pre { font-size:.8rem; }
  .toc { font-size:.84rem; }
  footer { font-size:.78rem; padding:1rem .8rem 1.6rem; }
}
@media (max-width:430px) {
  .hero h1 { font-size:1.32rem; }
  .cta .btn { display:block; width:100%; text-align:center; margin-bottom:.45rem; }
  .stat-grid { grid-template-columns:repeat(2,1fr); }
}
/* callouts + FAQ (used by the ELI20 page and notes) */
.callout { border-radius:12px; padding:.85rem 1rem; margin:1.1rem 0; border:1px solid var(--border);
  background:var(--surface); box-shadow:var(--shadow); }
.callout p { margin:.35rem 0; }
.callout p:first-child { margin-top:0; } .callout p:last-child { margin-bottom:0; }
.callout.info { border-left:4px solid var(--accent-2); background:#f4f9ff; }
.callout.tip { border-left:4px solid var(--ok); background:#f2fbf5; }
.callout.warn { border-left:4px solid var(--warn); background:#fffaf0; }
details.faq { background:var(--surface); border:1px solid var(--border); border-radius:10px;
  padding:.55rem .9rem; margin:.6rem 0; box-shadow:var(--shadow); }
details.faq summary { cursor:pointer; font-weight:600; }
details.faq[open] { padding-bottom:.7rem; }
details.faq p { color:#3b434d; }
@media (max-width:760px) { .callout { padding:.75rem .85rem; } }

/* brand + logo (masthead row, full content width) */
.brand { display:block; text-decoration:none; }
.brand .logo { display:block; width:100%; height:auto; border-radius:12px; }


/* stats row full width */
.stats { grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); }
@media (max-width: 760px) {
  .stats { grid-template-columns: repeat(2, 1fr); }
}

/* ---- responsive layer (auxiliary pages: session transcript) ---- */
pre{overflow:auto}
code{overflow-wrap:anywhere}
pre code{white-space:inherit}
main{overflow-wrap:break-word}
@media (max-width:900px){
  main{padding:1rem .8rem 2.5rem}
  main.narrow{max-width:none}
  .masthead .logo{max-height:72px;object-fit:contain}
  nav.mainnav .wrap{gap:.5rem .7rem}
  nav.mainnav a{font-size:.85rem}
  pre{font-size:.72rem;white-space:pre-wrap;word-break:break-word}
  table{display:block;overflow-x:auto;max-width:100%}
  h1{font-size:1.35rem} h2{font-size:1.12rem} h3{font-size:1rem}
  body{font-size:15px}
  img,video{max-width:100%;height:auto}
}
@media (max-width:600px){
  main{padding:.9rem .7rem 2.2rem}
  pre{font-size:.68rem}
  .masthead .logo{max-height:56px}
}