:root {
  --bg: #F4F5F7; --surface: #ffffff; --surface-2: #ebecf0;
  --ink: #0E0E10; --ink-2: #4a4c55; --ink-3: #6c6f79;
  --line: #e0e2e7; --accent: #D81B67; --brand: #FF3D8B; --brand-ink: #0E0E10;
  --warn: #9a5b00; --warn-soft: #fff3df;
  --code-bg: #0E0E10; --code-ink: #e4e5ea;
  --f-body: "IBM Plex Sans KR", system-ui, -apple-system, "Malgun Gothic", sans-serif;
  --f-mono: "IBM Plex Mono", ui-monospace, Menlo, Consolas, monospace;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0E0E10; --surface: #17171b; --surface-2: #1f1f24;
    --ink: #F4F5F7; --ink-2: #a9abb3; --ink-3: #80838c;
    --line: #2a2a30; --accent: #FF3D8B;
    --warn: #f0b860; --warn-soft: #2b2112;
    --code-bg: #08080a; --code-ink: #e4e5ea;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; }
body {
  margin: 0; background: var(--bg); color: var(--ink);
  font-family: var(--f-body); font-size: 16px; line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); }
a:hover { text-decoration-thickness: 2px; }
code, kbd {
  font-family: var(--f-mono); font-size: .88em;
  background: var(--surface-2); border: 1px solid var(--line); border-radius: 4px; padding: 1px 6px;
}
kbd { border-bottom-width: 2px; }
.wrap { max-width: 1080px; margin: 0 auto; padding-inline: 20px; }
@media (max-width: 600px) { .wrap { padding-inline: 16px; } }

/* nav */
.nav {
  position: sticky; top: 0; z-index: 10;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px); border-bottom: 1px solid var(--line);
}
.nav .wrap { display: flex; align-items: center; gap: 20px; height: 60px; }
.logo { display: flex; align-items: center; gap: 9px; font-weight: 700; font-size: 18px; color: var(--ink); text-decoration: none; }
.logo svg { flex: none; }
.nav ul { display: flex; gap: 18px; list-style: none; margin: 0 0 0 auto; padding: 0; align-items: center; }
.nav ul a { color: var(--ink-2); text-decoration: none; font-size: 14.5px; }
.nav ul a:hover, .nav ul a[aria-current="page"] { color: var(--ink); }
.lang {
  font-family: var(--f-mono); font-size: 12.5px !important; border: 1px solid var(--line);
  border-radius: 6px; padding: 3px 9px;
}
@media (max-width: 640px) {
  .nav ul { gap: 12px; }
  .nav ul .hide-sm { display: none; }
}

/* buttons */
.btn {
  display: inline-flex; align-items: center; gap: 9px; text-decoration: none;
  font-weight: 600; font-size: 15.5px; border-radius: 8px; padding: 12px 20px;
  border: 1px solid transparent; transition: filter .15s, transform .05s;
}
.btn:active { transform: translateY(1px); }
.btn.primary { background: var(--brand); color: var(--brand-ink); }
.btn.primary:hover { filter: brightness(1.08); }
.btn.ghost { border-color: var(--line); color: var(--ink); background: var(--surface); }
.btn.ghost:hover { border-color: var(--ink-3); }
.btn small { font-weight: 400; font-size: 12.5px; opacity: .85; font-family: var(--f-mono); }

/* hero */
.hero { padding: 72px 0 56px; }
.eyebrow {
  font-family: var(--f-mono); font-size: 12.5px; letter-spacing: .08em;
  color: var(--accent); margin: 0 0 14px; text-transform: uppercase;
}
.hero h1 { font-size: clamp(32px, 5.4vw, 52px); line-height: 1.18; letter-spacing: -.02em; margin: 0 0 18px; text-wrap: balance; }
.hero .lede { font-size: clamp(16.5px, 2vw, 19px); color: var(--ink-2); max-width: 62ch; margin: 0 0 28px; }
.cta { display: flex; gap: 12px; flex-wrap: wrap; }
.facts { display: flex; flex-wrap: wrap; gap: 8px 22px; margin: 26px 0 0; padding: 0; list-style: none; color: var(--ink-3); font-size: 14px; }
.facts li::before { content: "·"; margin-right: 8px; color: var(--accent); font-weight: 700; }
.facts li:first-child::before { content: none; }

/* sections */
section { padding: 56px 0; border-top: 1px solid var(--line); }
section h2 { font-size: clamp(24px, 3.4vw, 32px); letter-spacing: -.01em; margin: 0 0 10px; }
section .intro { color: var(--ink-2); margin: 0 0 30px; max-width: 66ch; }

.flow { display: grid; grid-template-columns: repeat(5, minmax(0, 1fr)); gap: 10px; counter-reset: s; list-style: none; padding: 0; margin: 0; }
.flow li {
  background: var(--surface); border: 1px solid var(--line); border-radius: 10px; padding: 14px 16px;
  font-weight: 600; position: relative;
}
.flow li::before {
  counter-increment: s; content: counter(s); display: block;
  font-family: var(--f-mono); font-size: 12px; color: var(--accent); font-weight: 500; margin-bottom: 2px;
}
.flow li span { display: block; font-weight: 400; font-size: 13.5px; color: var(--ink-2); }
@media (max-width: 760px) { .flow { grid-template-columns: 1fr 1fr; } }

.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(290px, 1fr)); gap: 14px; }
.card { background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 20px 22px; }
.card h3 { margin: 0 0 4px; font-size: 17.5px; }
.card .tag { font-family: var(--f-mono); font-size: 11.5px; color: var(--ink-3); margin: 0 0 10px; }
.card ul { margin: 0; padding-left: 18px; color: var(--ink-2); font-size: 14.5px; }
.card li { margin: 3px 0; }

.formats { display: grid; grid-template-columns: 160px 1fr; gap: 0; border: 1px solid var(--line); border-radius: 12px; overflow: hidden; background: var(--surface); }
.formats dt, .formats dd { margin: 0; padding: 12px 18px; border-bottom: 1px solid var(--line); }
.formats dt { font-weight: 600; background: var(--surface-2); }
.formats dd { color: var(--ink-2); font-family: var(--f-mono); font-size: 13.5px; }
.formats dt:last-of-type, .formats dd:last-of-type { border-bottom: none; }
@media (max-width: 600px) { .formats { grid-template-columns: 1fr; } .formats dt { border-bottom: none; padding-bottom: 4px; } }

.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 14px; }
.stat { background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 20px 22px; }
.stat b { display: block; font-family: var(--f-mono); font-size: 30px; font-weight: 500; letter-spacing: -.02em; color: var(--ink); }
.stat b s { color: var(--ink-3); font-size: 18px; margin-right: 8px; }
.stat span { color: var(--ink-2); font-size: 14px; }
.note { color: var(--ink-3); font-size: 13.5px; margin: 14px 0 0; }

.principles { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 22px; }
.principles h3 { font-size: 16px; margin: 0 0 4px; }
.principles p { margin: 0; color: var(--ink-2); font-size: 14.5px; }

/* download */
.dl { background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 28px; display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 24px; align-items: center; }
@media (max-width: 760px) { .dl { grid-template-columns: 1fr; } }
.dl h3 { margin: 0 0 6px; font-size: 20px; }
.dl dl { display: grid; grid-template-columns: auto minmax(0, 1fr); gap: 6px 16px; margin: 14px 0 0; font-size: 14px; }
.dl dt { color: var(--ink-3); }
.dl dd { margin: 0; color: var(--ink-2); }
.hash { font-family: var(--f-mono); font-size: 12.5px; word-break: break-all; }
.callout { margin-top: 18px; border-left: 3px solid var(--warn); background: var(--warn-soft); border-radius: 0 8px 8px 0; padding: 12px 16px; font-size: 14.5px; color: var(--ink); }

/* guide */
.guide { display: grid; grid-template-columns: 220px minmax(0, 1fr); gap: 48px; padding: 48px 0 24px; }
@media (max-width: 860px) { .guide { grid-template-columns: minmax(0, 1fr); gap: 8px; } .toc { position: static !important; } }
.toc { position: sticky; top: 84px; align-self: start; font-size: 14px; }
.toc p { font-family: var(--f-mono); font-size: 12px; letter-spacing: .08em; text-transform: uppercase; color: var(--ink-3); margin: 0 0 8px; }
.toc ol { margin: 0; padding-left: 20px; color: var(--ink-3); }
.toc li { margin: 5px 0; }
.toc a { color: var(--ink-2); text-decoration: none; }
.toc a:hover { color: var(--accent); }
.doc h1 { font-size: clamp(28px, 4.4vw, 40px); letter-spacing: -.02em; margin: 0 0 10px; }
.doc > .lede { color: var(--ink-2); margin: 0 0 18px; }
.doc h2 { font-size: 23px; margin: 48px 0 12px; padding-top: 22px; border-top: 1px solid var(--line); }
.doc h3 { font-size: 17px; margin: 26px 0 8px; }
.doc p, .doc li { color: var(--ink-2); }
.doc strong { color: var(--ink); }
.doc ol.steps { padding-left: 22px; }
.doc ol.steps > li { margin: 8px 0; padding-left: 4px; }
.doc table { width: 100%; border-collapse: collapse; font-size: 14.5px; background: var(--surface); border: 1px solid var(--line); border-radius: 10px; overflow: hidden; display: block; overflow-x: auto; }
.doc th, .doc td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--line); vertical-align: top; }
.doc th { background: var(--surface-2); font-weight: 600; white-space: nowrap; }
.doc tr:last-child td { border-bottom: none; }
.doc td:first-child { white-space: nowrap; color: var(--ink); font-weight: 500; }
pre {
  background: var(--code-bg); color: var(--code-ink); font-family: var(--f-mono); font-size: 13.5px;
  line-height: 1.75; padding: 16px 18px; border-radius: 10px; overflow-x: auto; margin: 12px 0;
}
pre code { background: none; border: none; padding: 0; color: inherit; font-size: inherit; }

/* footer */
footer { border-top: 1px solid var(--line); margin-top: 56px; padding: 28px 0 40px; color: var(--ink-3); font-size: 14px; }
footer .wrap { display: flex; flex-wrap: wrap; gap: 8px 24px; justify-content: space-between; }
footer a { color: var(--ink-2); }
.by { display: inline-flex; align-items: center; gap: 7px; text-decoration: none; color: var(--ink-2); }
.by:hover { color: var(--ink); }
.by svg { width: 18px; height: 18px; }
.by b { font-family: "Bricolage Grotesque", var(--f-body); font-weight: 800; font-size: 16px; letter-spacing: -.03em; color: var(--ink); }

/* compare */
.compare { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 14px; }
@media (max-width: 860px) { .compare { grid-template-columns: 1fr; } }
.cmp { background: var(--surface); border: 1px solid var(--line); border-radius: 12px; padding: 22px 24px; }
.cmp h3 { margin: 0 0 8px; font-size: 18px; }
.cmp p { margin: 0; color: var(--ink-2); font-size: 15px; }
.cmp.us { border: 2px solid var(--brand); }
.cmp.us h3 { color: var(--accent); }