/* ============================================================
   article.css — shared design system for long-form detail pages
   (ai_aec_interpreter, lennar_internship, future writeups)
   Minimal / technical: near-black structure + a single accent.
   To re-skin the whole site accent, change --accent below only.
   ============================================================ */
:root{
  --bg:#ffffff;
  --fg:#1a1d24;          /* near-black: text + structure */
  --muted:#5c6470;       /* secondary text */
  --line:#e6e8ec;        /* hairlines / borders */
  --ink-soft:#f6f7f9;    /* subtle fills (pre, abstract) */
  --accent:#0066cc;      /* the ONE accent — links & key figures */
  --accent-soft:#eaf2fb; /* faint accent tint (tags, callouts) */
  --max:1040px;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--fg);
  font-family:'Inter','Helvetica Neue',-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Arial,sans-serif;
  line-height:1.6;font-size:17px;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}
.wrap{max-width:var(--max);margin:0 auto;padding:0 24px}
a{color:var(--accent);text-decoration:none}
a:hover{text-decoration:underline}
code{font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,"Liberation Mono","Courier New",monospace;
  background:var(--ink-soft);padding:.15em .4em;border-radius:4px;font-size:.86em}

/* site nav (back link) */
nav.topnav{max-width:1120px;margin:18px auto 0;padding:0 24px}
nav.topnav a{font-size:.9rem;font-weight:600}

/* hero */
.hero .wrap{max-width:1120px}
header.hero{padding:40px 0;border-bottom:1px solid var(--line);text-align:center}
.hero h1{font-size:2.18rem;line-height:1.18;margin:0 auto 14px;letter-spacing:-.5px}
.hero h1 .title-line{display:block}
.hero h1 .title-line:last-child{white-space:nowrap}
.hero .sub{font-size:1.18rem;color:var(--muted);max-width:760px;margin:0 auto 8px}
.hero .authors{margin:18px 0 4px;font-size:1.02rem}
.hero .affil{color:var(--muted);font-size:.95rem;margin-bottom:26px}
.btns{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.btn{display:inline-flex;align-items:center;gap:8px;padding:10px 20px;border-radius:30px;
  background:var(--fg);color:#fff;font-weight:600;font-size:.96rem;border:1px solid var(--fg)}
.btn:hover{background:#000;text-decoration:none}
.btn.ghost{background:#fff;color:var(--fg)}
.btn.ghost:hover{background:var(--ink-soft)}

/* sections */
section{padding:52px 0}
h2{font-size:1.5rem;margin:0 0 10px;letter-spacing:-.3px}
h2 .num{color:var(--muted);font-size:1.0rem;font-weight:700;display:inline;
  text-transform:uppercase;letter-spacing:1.5px;vertical-align:.28em;margin-right:2px}
h2 .num::after{content:' | ';color:var(--accent);font-weight:700;letter-spacing:0;margin-left:3px}
h3{font-size:1.15rem;margin:1.4em 0 .4em}
.lead{color:var(--muted);max-width:780px;margin:0 0 24px}
p{margin:0 0 1em}
ul,ol{margin:0 0 1em;padding-left:1.4em}
li{margin-bottom:.4em}

/* media */
figure{margin:24px 0 8px}
figure img{width:100%;border:1px solid var(--line);border-radius:10px;display:block}
figure.fig-sm img{width:70%;margin-left:auto;margin-right:auto}
figcaption{color:var(--muted);font-size:.88rem;margin-top:10px;text-align:center}
.demo-video{width:100%;border:1px solid var(--line);border-radius:10px;display:block;margin:24px 0 8px}

/* meta key-value strip (project facts) */
.meta{display:grid;grid-template-columns:max-content 1fr;gap:6px 18px;
  margin:0 0 24px;font-size:.95rem}
.meta dt{color:var(--muted);font-weight:600}
.meta dd{margin:0}

/* abstract / soft panel */
.abstract{background:var(--ink-soft);border-radius:12px;padding:26px 30px;font-size:1.04rem}

/* contribution / feature cards */
.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-top:8px}
.cards.two{grid-template-columns:repeat(2,1fr)}
.card{border:1px solid var(--line);border-radius:12px;padding:22px}
.card h3{margin:0 0 8px;font-size:1.06rem}
.card .tag{display:inline-block;font-size:.72rem;font-weight:700;text-transform:uppercase;
  letter-spacing:1px;color:var(--accent);background:var(--accent-soft);
  padding:3px 9px;border-radius:20px;margin-bottom:10px}
.card p{margin:0;color:var(--muted);font-size:.95rem}

/* module cards (image + body) */
.mods{display:grid;grid-template-columns:repeat(2,1fr);gap:20px;margin-top:8px}
.mod{border:1px solid var(--line);border-radius:12px;overflow:hidden}
.mod img{width:100%;display:block;border-bottom:1px solid var(--line)}
.mod .body{padding:16px 18px}
.mod h3{margin:0 0 6px;font-size:1.05rem}
.mod p{margin:0;color:var(--muted);font-size:.92rem}
.mod .stack{margin-top:10px;font-size:.78rem;color:var(--accent);font-weight:600}

/* callout */
.callout{background:var(--accent-soft);border-left:4px solid var(--accent);
  border-radius:8px;padding:16px 20px;margin:0 0 26px;font-size:1.05rem}

/* two-column layout */
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:26px;align-items:start}

/* tables */
table{width:100%;border-collapse:collapse;font-size:.92rem;margin-top:6px}
th,td{text-align:left;padding:9px 10px;border-bottom:1px solid var(--line)}
th{font-size:.74rem;text-transform:uppercase;letter-spacing:.6px;color:var(--muted)}
tr.best td{background:var(--accent-soft);font-weight:600}
td.n,th.n{text-align:right;font-variant-numeric:tabular-nums}
.tcap{font-size:.82rem;color:var(--muted);margin-top:8px}

/* before / after lists */
.ba{display:grid;grid-template-columns:1fr 1fr;gap:18px;margin-top:8px}
.ba > div{border:1px solid var(--line);border-radius:12px;padding:20px}
.ba h3{margin:0 0 10px;font-size:1rem}
.ba.after h3{color:var(--accent)}
.ba ul{margin:0;padding-left:18px;color:var(--muted);font-size:.95rem}

/* code block */
pre{background:var(--ink-soft);border-radius:10px;padding:18px;overflow:auto;
  font-size:.85rem;line-height:1.5;border:1px solid var(--line)}
pre code{background:transparent;padding:0}

footer{padding:40px 0 70px;text-align:center;color:var(--muted);font-size:.92rem;
  border-top:1px solid var(--line)}

/* responsive */
@media(max-width:820px){
  .cards,.cards.two,.mods,.grid2,.ba{grid-template-columns:1fr}
  .hero h1{font-size:1.8rem}
  .hero h1 .title-line{display:inline}
  .hero h1 .title-line:last-child{white-space:normal}
  .meta{grid-template-columns:1fr}
  .meta dt{margin-top:6px}
}
@media(min-width:821px) and (max-width:1120px){
  .hero h1{font-size:1.95rem}
}

/* ---- supplement: enriched engineering content (index page) ---- */
.toolbar{display:flex;gap:12px;justify-content:center;flex-wrap:wrap;padding:30px 0 6px}
.res{margin-top:12px;font-size:.9rem;font-weight:700;color:var(--accent);
  border-top:1px solid var(--line);padding-top:10px}
.muted{color:var(--muted)}
.stack-note{margin-top:18px;color:var(--muted);font-size:.95rem;max-width:820px}
.badge{display:inline-block;font-size:.7rem;font-weight:700;letter-spacing:.5px;
  padding:2px 8px;border-radius:20px;color:#fff}
.badge.ans{background:#1f9d57}.badge.def{background:#d9822b}