/* Youngjun Kweon: wafer-and-process-traveler identity. Amber is the photolithography "yellow room" light. */
:root{
  --bg:#f3f4f2; --surface:#ffffff; --ink:#16191d; --muted:#5b6168; --line:#d9dcd8;
  --accent:#c98a00; --accent-ink:#8a5d00; --accent-wash:#fbf1d6;
  --die:#e3e6e2; --die-edge:#c9cdc8; --plate:#ffffff; --plate-edge:#d9dcd8;
  --f-display:"Bricolage Grotesque","Segoe UI",system-ui,sans-serif;
  --f-body:"IBM Plex Sans","Helvetica Neue",Arial,sans-serif;
  --f-mono:"IBM Plex Mono",ui-monospace,"SFMono-Regular",Menlo,monospace;
}
@media (prefers-color-scheme: dark){
  :root:not([data-theme="light"]){
    --bg:#101317; --surface:#171b20; --ink:#eceae4; --muted:#9aa0a7; --line:#2a3037;
    --accent:#f2b632; --accent-ink:#f5c55a; --accent-wash:#2b2413;
    --die:#1f252c; --die-edge:#2e363f; --plate:#f4f4f1; --plate-edge:#2a3037; color-scheme:dark;
  }
}
:root[data-theme="dark"]{
  --bg:#101317; --surface:#171b20; --ink:#eceae4; --muted:#9aa0a7; --line:#2a3037;
  --accent:#f2b632; --accent-ink:#f5c55a; --accent-wash:#2b2413;
  --die:#1f252c; --die-edge:#2e363f; --plate:#f4f4f1; --plate-edge:#2a3037; color-scheme:dark;
}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion: reduce){html{scroll-behavior:auto}}
body{margin:0;background:var(--bg);color:var(--ink);font-family:var(--f-body);font-size:1.0625rem;line-height:1.6;-webkit-font-smoothing:antialiased}
body::before{content:"";position:fixed;inset:0 0 auto;height:env(safe-area-inset-top,0px);z-index:10;background:var(--bg)}
img{max-width:100%;height:auto}
a{color:inherit}
a:focus-visible,button:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:2px}
sub{font-size:.72em;line-height:0}

.wrap{max-width:1120px;margin:0 auto;padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px))}

/* Nav */
.nav{position:sticky;top:env(safe-area-inset-top,0px);z-index:5;background:color-mix(in srgb,var(--bg) 90%,transparent);backdrop-filter:blur(8px);-webkit-backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.nav .wrap{display:flex;align-items:center;justify-content:space-between;gap:16px;padding-block:14px}
.mark{font-family:var(--f-display);font-weight:800;font-size:1.05rem;letter-spacing:-.01em;text-decoration:none;white-space:nowrap}
.mark span{color:var(--accent-ink)}
.nav ul{display:flex;gap:22px;list-style:none;margin:0;padding:0;font-size:.875rem;overflow-x:auto;scrollbar-width:none;min-width:0}
.nav ul::-webkit-scrollbar{display:none}
.nav a.l{text-decoration:none;color:var(--muted);white-space:nowrap}
.nav a.l:hover,.nav a.l[aria-current="page"]{color:var(--ink)}
.nav a.l[aria-current="page"]{box-shadow:inset 0 -2px 0 var(--accent)}

/* Shared bits */
.eyebrow{font-family:var(--f-mono);font-size:.78rem;letter-spacing:.08em;text-transform:uppercase;color:var(--accent-ink)}
.chip{display:inline-flex;align-items:center;gap:8px;font-family:var(--f-mono);font-size:.82rem;padding:8px 12px;border:1px solid var(--line);background:var(--surface);border-radius:999px;text-decoration:none;color:var(--ink);cursor:pointer}
.chip:hover{border-color:var(--accent)}
.chip.primary{background:var(--ink);color:var(--bg);border-color:var(--ink)}
.chip small{color:var(--muted);font-size:.72rem}
.chip.primary small{color:inherit;opacity:.7}
.chips{display:flex;flex-wrap:wrap;gap:10px}
h1,h2,h3{text-wrap:balance}
h2{font-family:var(--f-display);font-weight:700;font-size:clamp(1.7rem,3.6vw,2.4rem);line-height:1.08;letter-spacing:-.025em;margin:0}
h3{font-family:var(--f-display);font-weight:700;font-size:1.3rem;line-height:1.2;letter-spacing:-.015em;margin:0 0 4px}
.tag{display:inline-block;font-family:var(--f-mono);font-size:.72rem;letter-spacing:.06em;text-transform:uppercase;color:var(--accent-ink);margin-bottom:10px}
.meta{font-family:var(--f-mono);font-size:.8rem;color:var(--muted);margin:0 0 14px}

/* ---------- Home ---------- */
.hero .wrap{display:grid;grid-template-columns:1.15fr .85fr;gap:48px;align-items:center;padding-block:72px 56px}
.hero h1{font-family:var(--f-display);font-weight:800;font-size:clamp(3rem,8vw,5.6rem);line-height:.92;letter-spacing:-.035em;margin:.25em 0 .3em}
.lede{font-size:1.2rem;max-width:34ch;margin:0 0 28px}
.lede em{font-style:normal;background:linear-gradient(transparent 62%,var(--accent-wash) 62%)}
.wafer-box{position:relative;aspect-ratio:1;max-width:100%}
#wafer{width:100%;height:100%;display:block}
.wafer-cap{position:absolute;left:0;bottom:-6px;font-family:var(--f-mono);font-size:.72rem;color:var(--muted)}

.facts{border-block:1px solid var(--line);background:var(--surface)}
.facts .wrap{display:grid;grid-template-columns:repeat(4,1fr)}
.fact{padding:22px 20px 22px 0;border-right:1px solid var(--line);min-width:0}
.fact + .fact{padding-left:20px}
.fact:last-child{border-right:0}
.fact b{display:block;font-family:var(--f-display);font-size:1.6rem;font-weight:700;letter-spacing:-.02em;font-variant-numeric:tabular-nums}
.fact span{font-size:.85rem;color:var(--muted)}

section.blk .wrap{padding-block:88px 24px}
.sec-head{display:grid;grid-template-columns:220px 1fr;gap:32px;margin-bottom:40px}
.sec-head .eyebrow{padding-top:10px}
.sec-head p{color:var(--muted);max-width:60ch;margin:12px 0 0}
.indent{margin-left:252px}

.about{display:grid;grid-template-columns:260px 1fr;gap:36px;align-items:start}
.about img{width:100%;aspect-ratio:4/5;object-fit:cover;object-position:50% 30%;display:block;border:1px solid var(--line)}
.about p{margin:0 0 14px;max-width:62ch}
.about > *{min-width:0}

.now{display:grid;grid-template-columns:repeat(2,1fr);gap:20px}
.now article,.card{background:var(--surface);border:1px solid var(--line);padding:26px;min-width:0}
.now article.hl{border-color:var(--accent);box-shadow:inset 0 3px 0 var(--accent)}
.now ul,.role ul{margin:0;padding-left:1.1em}
.now li,.role li{margin-bottom:6px}

.roles{border-top:1px solid var(--line)}
.role{display:grid;grid-template-columns:1fr 1.5fr;gap:32px;padding-block:32px;border-bottom:1px solid var(--line)}
.role > *{min-width:0}
.role .pi{color:var(--muted);font-size:.95rem;margin:6px 0 0}
.pub{margin-top:16px;display:inline-block;font-size:.85rem;padding:6px 10px;background:var(--accent-wash);color:var(--accent-ink);font-weight:500}
.more{display:inline-block;margin-top:16px;font-family:var(--f-mono);font-size:.82rem;color:var(--accent-ink);text-decoration:none;border-bottom:1px solid currentColor}
.more:hover{color:var(--ink)}

.traveler{background:var(--surface);border:1px solid var(--line);overflow-x:auto}
.traveler table{width:100%;border-collapse:collapse;min-width:640px;font-size:.95rem}
.traveler th{font-family:var(--f-mono);font-weight:500;font-size:.72rem;letter-spacing:.07em;text-transform:uppercase;color:var(--muted);text-align:left;padding:14px 18px;border-bottom:1px solid var(--line)}
.traveler td{padding:16px 18px;border-bottom:1px solid var(--line);vertical-align:top}
.traveler tr:last-child td{border-bottom:0}
.traveler td.n{font-family:var(--f-mono);color:var(--accent-ink);font-variant-numeric:tabular-nums;width:56px}
.traveler td.step{font-weight:600;width:24%}
.traveler td.step a{text-decoration:none;border-bottom:1px solid var(--accent)}
.traveler td.tool{font-family:var(--f-mono);font-size:.82rem;width:24%}
.traveler td.why{color:var(--muted)}
.traveler tr:hover td{background:var(--accent-wash)}
.trav-note{margin:14px 0 0;font-size:.85rem;color:var(--muted)}

.skills{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.skill{min-width:0}
.skill h4{font-family:var(--f-mono);font-weight:500;font-size:.75rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);margin:0 0 12px;padding-bottom:10px;border-bottom:1px solid var(--line)}
.pills{display:flex;flex-wrap:wrap;gap:6px}
.pills span{font-size:.85rem;padding:4px 10px;border:1px solid var(--line);background:var(--surface)}
.two{display:grid;grid-template-columns:1fr 1fr;gap:20px}
.card p{margin:0;color:var(--muted)}

.notes{list-style:none;margin:0;padding:0;border-top:1px solid var(--line)}
.notes li{border-bottom:1px solid var(--line)}
.notes a{display:grid;grid-template-columns:56px 1fr auto;gap:16px;align-items:baseline;padding:18px 0;text-decoration:none}
.notes a:hover .t{color:var(--accent-ink)}
.notes .n{font-family:var(--f-mono);font-size:.85rem;color:var(--accent-ink)}
.notes .t{font-family:var(--f-display);font-weight:700;font-size:1.25rem;letter-spacing:-.01em}
.notes .d{color:var(--muted);font-size:.9rem}

/* ---------- Article pages ---------- */
.page-head{border-bottom:1px solid var(--line);background:var(--surface)}
.page-head .wrap{padding-block:56px 40px}
.crumb{font-family:var(--f-mono);font-size:.78rem;color:var(--muted);margin-bottom:18px}
.crumb a{text-decoration:none;color:var(--muted)}
.crumb a:hover{color:var(--ink)}
.page-head h1{font-family:var(--f-display);font-weight:800;font-size:clamp(2.3rem,6vw,4rem);line-height:.98;letter-spacing:-.03em;margin:.2em 0 .35em;max-width:18ch}
.page-head .lede{max-width:60ch;color:var(--muted);font-size:1.15rem;margin-bottom:24px}
.page-head .chips{margin-top:4px}

.doc .wrap{display:grid;grid-template-columns:220px minmax(0,1fr);gap:32px;padding-block:48px 24px}
.toc{position:sticky;top:calc(env(safe-area-inset-top,0px) + 76px);align-self:start;font-size:.88rem}
.toc p{font-family:var(--f-mono);font-size:.72rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);margin:0 0 10px}
.toc ol{list-style:none;margin:0;padding:0;border-left:1px solid var(--line)}
.toc a{display:block;padding:5px 0 5px 14px;margin-left:-1px;border-left:2px solid transparent;text-decoration:none;color:var(--muted);line-height:1.35}
.toc a:hover{color:var(--ink)}
.toc a.on{color:var(--ink);border-left-color:var(--accent)}

.prose{max-width:74ch;min-width:0}
.prose > h2{margin:56px 0 18px;padding-top:20px;border-top:1px solid var(--line);scroll-margin-top:90px}
.prose > h2:first-child{margin-top:0;border-top:0;padding-top:0}
.prose h3{margin:32px 0 10px;scroll-margin-top:90px}
.prose p{margin:0 0 14px}
.prose ul,.prose ol{margin:0 0 16px;padding-left:1.25em}
.prose li{margin-bottom:7px}
.prose li > ul,.prose li > ol{margin:8px 0 4px}
.prose a{color:var(--accent-ink);text-underline-offset:3px}
.prose strong{font-weight:600}
.kicker{font-family:var(--f-mono);font-size:.85rem;color:var(--accent-ink)}
.eq{font-family:var(--f-mono);font-size:.95rem;background:var(--surface);border:1px solid var(--line);border-left:3px solid var(--accent);padding:12px 16px;overflow-x:auto;line-height:1.8}
.callout{background:var(--accent-wash);padding:14px 18px;border-left:3px solid var(--accent)}

.prose table{width:100%;border-collapse:collapse;font-size:.93rem;margin:0 0 20px;background:var(--surface);border:1px solid var(--line)}
.tbl{overflow-x:auto;margin:0 0 20px}
.tbl table{margin:0;min-width:520px}
.prose th{text-align:left;font-family:var(--f-mono);font-weight:500;font-size:.72rem;letter-spacing:.07em;text-transform:uppercase;color:var(--muted);padding:12px 14px;border-bottom:1px solid var(--line)}
.prose td{padding:12px 14px;border-bottom:1px solid var(--line);vertical-align:top}
.prose tr:last-child td{border-bottom:0}
.prose td:first-child{font-weight:600;white-space:nowrap}

ol.flow{list-style:none;padding:0;display:flex;flex-wrap:wrap;gap:8px 6px;counter-reset:f;margin:6px 0 20px}
ol.flow li{counter-increment:f;margin:0;display:flex;align-items:center;gap:8px;font-size:.88rem;padding:6px 12px 6px 8px;background:var(--surface);border:1px solid var(--line)}
ol.flow li::before{content:counter(f,decimal-leading-zero);font-family:var(--f-mono);font-size:.72rem;color:var(--accent-ink)}

.fig{margin:24px 0 28px}
.fig .plate{background:var(--plate);border:1px solid var(--plate-edge);padding:14px;display:block}
.fig img{display:block;margin:0 auto;max-height:720px;width:auto}
.fig figcaption{font-size:.85rem;color:var(--muted);margin-top:8px}
.pair{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.pair .fig{margin:8px 0}
.split{display:grid;grid-template-columns:1.4fr 1fr;gap:32px;align-items:start}
.split > *{min-width:0}
.split .fig{margin-top:0}
.split h2{margin:0 0 16px}

.steps > p{margin:24px 0 8px;font-family:var(--f-display);font-size:1.1rem}
.steps > p:first-child{margin-top:8px}
.results{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:0 0 20px}
.results div{background:var(--surface);border:1px solid var(--line);padding:16px 18px;min-width:0}
.results b{display:block;font-family:var(--f-display);font-size:1.05rem;margin-bottom:4px}
.results span{color:var(--muted);font-size:.93rem}

.org{display:grid;grid-template-columns:140px minmax(0,1fr);gap:32px;padding-block:8px 40px;margin-bottom:40px;border-bottom:1px solid var(--line)}
.org:last-child{border-bottom:0}
.org > p{margin:0}
.org img.logo{width:140px;height:140px;object-fit:contain;background:var(--plate);border:1px solid var(--plate-edge);padding:12px;display:block}
.org h2{margin:0 0 6px!important;padding:0!important;border:0!important}
.out a{font-family:var(--f-mono);font-size:.85rem}

.pager{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin-top:56px}
.pager a{display:block;padding:18px 20px;border:1px solid var(--line);background:var(--surface);text-decoration:none;min-width:0}
.pager a:hover{border-color:var(--accent)}
.pager small{display:block;font-family:var(--f-mono);font-size:.72rem;letter-spacing:.07em;text-transform:uppercase;color:var(--muted);margin-bottom:4px}
.pager b{font-family:var(--f-display);font-size:1.1rem}
.pager .next{text-align:right;grid-column:2}

.fm{background:var(--surface);border:1px solid var(--line);padding:4px 22px 18px;margin:0 0 24px}
.fm h3{margin-top:20px}
.fm .pair{align-items:end}
.pfr{padding:10px 14px;border-left:3px solid var(--muted);background:var(--bg);margin:0 0 10px!important}
.pfr b{font-family:var(--f-mono);font-size:.72rem;letter-spacing:.08em;text-transform:uppercase;margin-right:10px}
.pfr.problem{border-left-color:#c2462e}
.pfr.problem b{color:#c2462e}
.pfr.fix{border-left-color:var(--accent)}
.pfr.fix b{color:var(--accent-ink)}
.pfr.result{border-left-color:#2f8a57}
.pfr.result b{color:#2f8a57}
/* Footer */
footer{margin-top:96px;background:var(--ink);color:var(--bg)}
footer .wrap{padding-block:56px;display:grid;grid-template-columns:1fr auto;gap:32px;align-items:end}
footer h2{color:var(--bg)}
footer p{opacity:.7;margin:10px 0 0;max-width:46ch}
footer .chip{background:transparent;color:var(--bg);border-color:color-mix(in srgb,var(--bg) 30%,transparent)}
footer .chip small{color:inherit;opacity:.65}
.fine{font-family:var(--f-mono);font-size:.72rem;opacity:.55;grid-column:1/-1;margin-top:8px}
.toast{position:fixed;left:50%;bottom:calc(20px + env(safe-area-inset-bottom,0px));transform:translateX(-50%);background:var(--ink);color:var(--bg);font-size:.85rem;padding:8px 14px;border-radius:4px;opacity:0;transition:opacity .2s;pointer-events:none;z-index:20}
.toast.on{opacity:1}

@media (max-width:900px){
  .hero .wrap{grid-template-columns:1fr;gap:32px;padding-block:48px 40px}
  .wafer-box{max-width:340px}
  .sec-head{grid-template-columns:1fr;gap:6px}
  .sec-head .eyebrow{padding-top:0}
  .indent{margin-left:0}
  .role{grid-template-columns:1fr;gap:12px}
  .facts .wrap{grid-template-columns:repeat(2,1fr)}
  .fact{padding:18px 12px 18px 0}
  .fact + .fact{padding-left:0}
  .fact:nth-child(2n){padding-left:16px;border-right:0}
  .fact:nth-child(-n+2){border-bottom:1px solid var(--line)}
  .skills{grid-template-columns:1fr 1fr}
  footer .wrap{grid-template-columns:1fr}
  .doc .wrap{grid-template-columns:1fr;gap:0;padding-block:32px 16px}
  .toc{display:none}
  .split{grid-template-columns:1fr}
}
@media (max-width:620px){
  .nav ul{gap:16px}
  .about{grid-template-columns:1fr}
  .about img{max-width:240px}
  .now,.two,.skills,.results,.pair{grid-template-columns:1fr}
  .notes a{grid-template-columns:40px 1fr}
  .notes .d{grid-column:2}
  section.blk .wrap{padding-block:64px 16px}
  .org{grid-template-columns:1fr;gap:16px}
  .org img.logo{width:96px;height:96px}
  .pager{grid-template-columns:1fr}
  .pager .next{grid-column:1}
  .prose td:first-child{white-space:normal}
}