:root{--paper:#fafaf7;--subtle:#f2f2ed;--ink:#17181a;--muted:#54575c;--quiet:#6b6e73;--line:rgba(23,24,26,.11);--line-strong:rgba(23,24,26,.24);--sans:"Inter","Pretendard",-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;--mono:"IBM Plex Mono",ui-monospace,SFMono-Regular,Menlo,Consolas,monospace}
*{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:80px}
body{margin:0;background:var(--paper);color:var(--ink);font-family:var(--sans);line-height:1.7;word-break:keep-all;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility}
a{color:inherit;text-decoration:none}
::selection{background:var(--ink);color:var(--paper)}
a:focus-visible,summary:focus-visible{outline:2px solid var(--ink);outline-offset:5px}
.wrap{width:100%;max-width:1120px;padding:0 24px;margin:0 auto}
.skip{position:fixed;top:-70px;left:16px;padding:12px;background:#fff;z-index:100}
.skip:focus{top:10px}

/* header */
header{position:fixed;top:0;left:0;right:0;z-index:80;background:rgba(250,250,247,.92);backdrop-filter:blur(12px);border-bottom:1px solid var(--line)}
.nav{height:60px;display:flex;align-items:center;justify-content:space-between;gap:24px}
.brand{font-size:14px;font-weight:700;letter-spacing:.26em;display:inline-flex;align-items:center;gap:17px}
.brand small{border-left:1px solid var(--line-strong);padding-left:17px;font-family:var(--mono);font-size:11px;font-weight:400;letter-spacing:.08em;color:var(--quiet)}
.navlinks{display:flex;align-items:center;gap:24px;font-family:var(--mono);font-size:11.5px;letter-spacing:.06em;color:var(--muted)}
.navlinks a:hover{color:var(--ink);text-decoration:underline;text-underline-offset:5px}

/* hero */
.hero{padding:104px 0 44px;border-bottom:1px solid var(--line)}
.eyebrow{display:flex;align-items:center;gap:10px;font-family:var(--mono);font-size:11.5px;letter-spacing:.12em;color:var(--quiet);text-transform:uppercase;margin-bottom:18px}
.dot{width:8px;height:8px;border:1.5px solid var(--quiet);border-radius:50%;flex:none}
h1{font-size:clamp(32px,4.6vw,54px);line-height:1.2;font-weight:700;letter-spacing:-.045em;margin:0;max-width:18ch}
h1 span{color:var(--quiet)}
.lead{font-size:clamp(14.5px,1.6vw,16.5px);color:var(--muted);line-height:1.75;max-width:58ch;margin:18px 0 0}
.hero-note{font-family:var(--mono);font-size:11px;color:var(--quiet);margin:20px 0 0}
.btn{display:inline-flex;align-items:center;gap:14px;background:var(--ink);color:var(--paper);padding:12px 22px;border-radius:4px;font-family:var(--mono);font-size:12.5px;font-weight:500;transition:opacity .2s,transform .2s}
.btn:hover{opacity:.85;transform:translateY(-1px)}

.definition{display:grid;grid-template-columns:1fr 2fr;gap:40px;border-bottom:1px solid var(--line);padding:22px 0;align-items:center}
.definition strong{font-size:14px;font-weight:600}
.definition strong span{display:block;font-family:var(--mono);font-size:10px;letter-spacing:.04em;font-weight:400;color:var(--quiet);margin-top:5px}
.definition p{margin:0;font-size:13px;line-height:1.8;color:var(--muted)}

/* sections */
.section{padding:44px 0}
.section-top{display:flex;justify-content:space-between;align-items:flex-end;gap:32px;margin-bottom:24px}
.section-tag{font-family:var(--mono);font-size:11.5px;font-weight:500;letter-spacing:.14em;color:var(--muted);margin-bottom:11px}
.section-tag::before{content:attr(data-index);color:var(--quiet);letter-spacing:0;margin-right:14px;font-weight:400}
h2{font-weight:600;font-size:clamp(20px,2.3vw,26px);line-height:1.4;letter-spacing:-.025em;margin:0}
.section-top>p{font-size:13px;color:var(--muted);line-height:1.75;margin:0}
.cards{border-top:1px solid var(--line)}
.card{display:grid;grid-template-columns:150px 220px 1fr;gap:10px 24px;padding:19px 0;border-bottom:1px solid var(--line);align-items:baseline}
.card-num{font-family:var(--mono);font-size:11px;color:var(--quiet)}
.card h3{font-size:15.5px;font-weight:600;letter-spacing:-.01em;margin:0}
.card p{font-size:13.5px;color:var(--muted);margin:0;line-height:1.75}
.card-bottom{grid-column:3;font-family:var(--mono);font-size:11px;color:var(--quiet)}

.process-band{background:var(--subtle)}
.process{padding-top:44px;padding-bottom:44px}
.steps{display:grid;grid-template-columns:repeat(4,1fr);gap:22px;margin-top:26px}
.step{border-top:1px solid var(--line-strong);padding-top:15px}
.step b{font-family:var(--mono);font-size:11px;font-weight:400;color:var(--quiet)}
.step h3{font-size:15.5px;font-weight:600;margin:11px 0 8px}
.step p{font-size:13px;color:var(--muted);line-height:1.75;margin:0}

/* faq */
.faq{display:grid;grid-template-columns:1fr 1.6fr;gap:56px}
details{border-bottom:1px solid var(--line)}
details:first-of-type{border-top:1px solid var(--line)}
summary{cursor:pointer;list-style:none;position:relative;padding:16px 32px 16px 0;font-size:14px;font-weight:500}
summary::-webkit-details-marker{display:none}
summary:after{content:"+";position:absolute;right:3px;top:13px;font-family:var(--mono);font-size:20px;font-weight:400;color:var(--quiet)}
details[open] summary:after{content:"−"}
details p{font-size:13px;line-height:1.85;color:var(--muted);margin:0;padding:0 24px 18px 0}

.closing{padding:44px 0 48px;border-top:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;gap:32px}
.closing p{font-size:14px;color:var(--muted);margin:16px 0 0}
.status{font-family:var(--mono);font-size:12px;color:var(--quiet);padding-bottom:8px;border-bottom:1px solid var(--line-strong);white-space:nowrap}

footer{border-top:1px solid var(--line)}
.footer{display:flex;align-items:center;justify-content:space-between;gap:20px;padding-top:22px;padding-bottom:22px}
.footer .brand{font-size:12px}
.footer>span,.footer nav{font-family:var(--mono);font-size:11px;color:var(--quiet)}
.footer nav a{margin-left:18px}
.footer nav a:hover{color:var(--ink)}

/* ── blog list ── */
.page-head{padding:104px 0 32px;border-bottom:1px solid var(--line)}
.page-head h1{font-size:clamp(28px,4vw,44px);max-width:22ch}
.page-head .lead{margin-top:16px}
.postlist{border-top:1px solid var(--line);margin:0;padding:0;list-style:none}
.postlist li{border-bottom:1px solid var(--line)}
.postlist a{display:grid;grid-template-columns:150px 1fr 150px;gap:8px 24px;padding:22px 0;align-items:baseline;transition:opacity .2s}
.postlist a:hover{opacity:.62}
.postlist .meta{font-family:var(--mono);font-size:11px;color:var(--quiet)}
.postlist h2{font-size:17px;font-weight:600;margin:0}
.postlist p{font-size:13.5px;color:var(--muted);line-height:1.75;margin:7px 0 0;grid-column:2;max-width:62ch}
.postlist .go{font-family:var(--mono);font-size:11px;color:var(--quiet);text-align:right}

/* ── article ── */
.article-head{padding:100px 0 26px;border-bottom:1px solid var(--line)}
.crumb{font-family:var(--mono);font-size:11px;letter-spacing:.06em;color:var(--quiet);margin-bottom:18px}
.crumb a:hover{color:var(--ink);text-decoration:underline;text-underline-offset:4px}
.article-head h1{font-size:clamp(27px,3.6vw,40px);line-height:1.28;max-width:24ch}
.article-meta{font-family:var(--mono);font-size:11px;color:var(--quiet);margin-top:18px;display:flex;gap:18px;flex-wrap:wrap}
.article-layout{display:grid;grid-template-columns:200px 1fr;gap:56px;padding:36px 0 48px;align-items:start}
.toc{position:sticky;top:88px;font-family:var(--mono);font-size:11.5px;line-height:1.9;color:var(--quiet)}
.toc b{display:block;letter-spacing:.12em;color:var(--muted);margin-bottom:10px;font-weight:500}
.toc a{display:block;padding:2px 0}
.toc a:hover{color:var(--ink)}
.prose{max-width:70ch;font-size:15.5px;line-height:1.85}
.prose>p{color:var(--muted);margin:0 0 18px}
.prose .summary{background:var(--subtle);border-left:2px solid var(--ink);padding:18px 22px;font-size:14.5px;color:var(--ink);margin:0 0 30px;line-height:1.8}
.prose h2{font-size:21px;margin:38px 0 14px;letter-spacing:-.02em;scroll-margin-top:86px}
.prose h3{font-size:16.5px;font-weight:600;margin:26px 0 10px}
.prose ul,.prose ol{color:var(--muted);margin:0 0 18px;padding-left:20px}
.prose li{margin-bottom:8px}
.prose strong{color:var(--ink);font-weight:600}
.prose table{width:100%;border-collapse:collapse;margin:0 0 22px;font-size:14px}
.prose th,.prose td{text-align:left;padding:11px 12px;border-bottom:1px solid var(--line);vertical-align:top;color:var(--muted)}
.prose th{font-family:var(--mono);font-size:11px;font-weight:500;letter-spacing:.06em;color:var(--ink);border-bottom:1px solid var(--line-strong);text-transform:uppercase}
.prose td:first-child{color:var(--ink);font-weight:500;width:26%}
.prose blockquote{margin:0 0 22px;padding-left:20px;border-left:2px solid var(--line-strong);color:var(--quiet);font-size:14.5px}
.prose .qa{border-top:1px solid var(--line);margin-top:34px;padding-top:6px}
.prose .qa h2{margin-top:22px}
.prose a.inline{text-decoration:underline;text-underline-offset:3px;color:var(--ink)}
.next{border-top:1px solid var(--line);padding:26px 0 44px;display:flex;justify-content:space-between;gap:24px;align-items:center;flex-wrap:wrap}
.next span{font-family:var(--mono);font-size:11px;color:var(--quiet)}

@media(max-width:820px){
  .hero{padding:88px 0 36px}.section{padding:36px 0}
  .card{grid-template-columns:120px 1fr;gap:8px 20px}.card p,.card-bottom{grid-column:2}
  .steps{grid-template-columns:1fr 1fr;gap:22px}
  .faq{gap:28px}.definition{gap:24px}.navlinks{gap:16px}
  .process{padding-top:36px;padding-bottom:36px}
  .article-layout{grid-template-columns:1fr;gap:0;padding-top:26px}
  .toc{position:static;border-bottom:1px solid var(--line);padding-bottom:18px;margin-bottom:26px}
  .toc a{display:inline-block;margin-right:16px}
  .page-head,.article-head{padding-top:88px}
  .postlist a{grid-template-columns:110px 1fr}.postlist .go{display:none}
}
@media(max-width:540px){
  .navlinks>a:not(.nav-cta){display:none}
  .brand{gap:12px}.brand small{padding-left:12px}.navlinks{font-size:11px}
  .eyebrow{font-size:10px;letter-spacing:.07em}
  h1{font-size:34px;letter-spacing:-.05em}
  .definition{grid-template-columns:1fr;gap:12px;padding:20px 0}
  .section-top{display:block}.section-top>p{margin-top:16px}
  .card{grid-template-columns:1fr;gap:6px;padding:18px 0}
  .card p,.card-bottom{grid-column:1}.card h3{margin:4px 0}.card-bottom{margin-top:4px}
  .faq{grid-template-columns:1fr;gap:24px}
  .closing{display:block;padding:36px 0 40px}.status{display:inline-block;margin-top:22px}
  .footer{align-items:flex-start;flex-wrap:wrap;gap:10px}.footer>span{font-size:10px}
  .footer nav a{margin:0 18px 0 0}
  .step p br{display:none}
  .postlist a{grid-template-columns:1fr;gap:4px;padding:20px 0}
  .postlist p{grid-column:1}
  .prose{font-size:15px}
  .prose table,.prose thead,.prose tbody,.prose tr,.prose th,.prose td{display:block}
  .prose thead{display:none}
  .prose tr{border-bottom:1px solid var(--line);padding:10px 0}
  .prose td{border:0;padding:3px 0;width:auto!important}
  .prose td:first-child{width:auto}
}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}.btn{transition:none}.btn:hover{transform:none}}