:root {
  --paper-50: #faf9f6;
  --paper-100: #f7f6f3;
  --paper-200: #eeece5;
  --paper-300: #e3e0d5;
  --ink-950: #121312;
  --ink-900: #272826;
  --ink-700: #3b3f3a;
  --ink-600: #5c5b56;
  --ink-500: #656a62;
  --ink-400: #8c9288;
  --ink-300: #9ea59a;
  --line-100: rgba(18, 19, 18, 0.06);
  --line-200: rgba(18, 19, 18, 0.09);
  --line-400: rgba(18, 19, 18, 0.18);
  --line-dark: rgba(247, 246, 243, 0.12);
  --rust: #d9381e;
  --rust-hover: #b82d16;
  --rust-soft: rgba(217, 56, 30, 0.08);
  --emerald: #059669;
  --emerald-soft: rgba(5, 150, 105, 0.12);
  --bg: var(--paper-100);
  --surface: #ffffff;
  --subtle: var(--paper-200);
  --fg: var(--ink-950);
  --fg-2: var(--ink-700);
  --fg-mute: var(--ink-500);
  --border: var(--line-200);
  --gutter: clamp(1.25rem, 4vw, 3.25rem);
  --container: 78rem;
  --narrow: 54rem;
  --section: clamp(4.5rem, 3.5rem + 4.5vw, 8rem);
  --font-display: "Space Grotesk", Pretendard, "Apple SD Gothic Neo", -apple-system, sans-serif;
  --font-sans: Pretendard, "Apple SD Gothic Neo", -apple-system, BlinkMacSystemFont, "Noto Sans KR", sans-serif;
  --font-mono: "Space Mono", ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  --radius: 12px;
  --radius-lg: 16px;
  --radius-xl: 22px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.03), 0 8px 24px -4px rgba(0, 0, 0, 0.04);
  --ease: cubic-bezier(0.16, 1, 0.3, 1);
  --header-h: 72px;
}

*,
*::before,
*::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 5.5rem;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  background: var(--bg);
  color: var(--fg);
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 0.975rem;
  line-height: 1.7;
  background: var(--bg);
  color: var(--fg);
}

img, svg { display: block; max-width: 100%; }
a { color: inherit; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; }
code, kbd, pre { font-family: var(--font-mono); }

.skip {
  position: absolute;
  left: 1rem;
  top: -4rem;
  z-index: 9999;
  padding: 0.5rem 0.9rem;
  background: var(--ink-950);
  color: var(--paper-50);
  border-radius: 999px;
}
.skip:focus { top: 1rem; }

.wrap {
  width: min(100% - 2 * var(--gutter), var(--container));
  margin-inline: auto;
}

.header {
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid var(--border);
  background: rgba(247, 246, 243, 0.9);
  backdrop-filter: blur(12px);
}

.header-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  height: var(--header-h);
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
}

.brand-mark {
  width: 36px;
  height: 36px;
  border-radius: 6px;
  overflow: hidden;
  flex-shrink: 0;
  transition: transform 150ms var(--ease);
}
.brand:hover .brand-mark { transform: scale(1.05); }

.brand-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.9375rem;
  letter-spacing: -0.02em;
  line-height: 1.15;
}
.brand-sub {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--fg-mute);
}

.nav-desk {
  display: none;
  align-items: center;
  gap: 1.7rem;
}
.nav-desk a {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 500;
  text-decoration: none;
  color: rgba(18, 19, 18, 0.8);
  transition: color 150ms var(--ease);
}
.nav-desk a:hover { color: var(--rust); }

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.pill {
  display: none;
  align-items: center;
  gap: 0.5rem;
  border: 1px solid var(--border);
  background: rgba(238, 236, 229, 0.6);
  border-radius: 999px;
  padding: 0.25rem 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 600;
  color: var(--fg-mute);
}

.dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--emerald);
  position: relative;
}
.dot::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: 50%;
  background: var(--emerald);
  animation: ping 1.6s cubic-bezier(0, 0, 0.2, 1) infinite;
}
@keyframes ping {
  75%, 100% { transform: scale(2.2); opacity: 0; }
}

.btn-ghost,
.lang-switch {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  background: var(--paper-50);
  text-decoration: none;
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--fg);
  transition: background 150ms var(--ease), color 150ms var(--ease), border-color 150ms var(--ease);
}
.btn-ghost {
  border-radius: 999px;
  padding: 0.3rem 0.85rem;
  font-size: 0.75rem;
}
.lang-switch {
  width: 32px;
  height: 32px;
  border-radius: 999px;
  font-size: 0.75rem;
}
.btn-ghost:hover,
.lang-switch:hover {
  border-color: var(--ink-950);
  background: var(--ink-950);
  color: var(--paper-50);
}

.nav-strip {
  display: flex;
  gap: 1.25rem;
  overflow-x: auto;
  border-top: 1px solid var(--border);
  padding: 0.5rem var(--gutter);
  -webkit-overflow-scrolling: touch;
}
.nav-strip a {
  flex-shrink: 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  text-decoration: none;
  color: rgba(18, 19, 18, 0.8);
}
.nav-strip a:hover { color: var(--rust); }

@media (min-width: 1100px) {
  .nav-desk { display: flex; }
  .pill { display: inline-flex; }
  .nav-strip { display: none; }
}

.hero {
  border-bottom: 1px solid var(--border);
  padding: clamp(2.5rem, 2rem + 3vw, 5rem) 0 clamp(3.5rem, 2.5rem + 4vw, 6.5rem);
}
.hero-grid {
  display: grid;
  gap: 3rem;
}
@media (min-width: 960px) {
  .hero-grid {
    grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr);
    align-items: center;
    gap: 3rem;
  }
}

.meta-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.65rem;
}
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  border: 1px solid var(--border);
  background: var(--subtle);
  border-radius: 999px;
  padding: 0.2rem 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--fg-mute);
}
.badge .sq {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--rust);
}
.geo {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--fg-mute);
}

h1 {
  margin: 1.4rem 0 0;
  font-family: var(--font-display);
  font-size: clamp(2.15rem, 1.3rem + 3.4vw, 4.4rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.08;
  text-wrap: balance;
}
h1 .rust { color: var(--rust); }

.lede {
  margin: 1.5rem 0 0;
  border-left: 3px solid var(--rust);
  padding-left: 1.2rem;
  max-width: 42rem;
  font-size: 1.05rem;
  line-height: 1.75;
  color: rgba(18, 19, 18, 0.9);
  text-wrap: pretty;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
  margin-top: 2.2rem;
}
.btn-primary,
.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  border-radius: 999px;
  padding: 0.85rem 1.45rem;
  font-family: var(--font-display);
  font-size: 0.9375rem;
  font-weight: 700;
  text-decoration: none;
  transition: transform 150ms var(--ease), background 150ms var(--ease), border-color 150ms var(--ease);
}
.btn-primary {
  background: var(--ink-950);
  color: var(--paper-50);
  box-shadow: var(--shadow);
}
.btn-primary:hover { background: var(--rust); transform: translateY(-2px); }
.btn-secondary {
  border: 1px solid var(--border);
  background: var(--paper-50);
  color: var(--fg);
}
.btn-secondary:hover {
  border-color: var(--ink-950);
  background: var(--subtle);
  transform: translateY(-2px);
}

.machine {
  border: 1px solid var(--border);
  background: var(--surface);
  border-radius: var(--radius-xl);
  padding: 1.2rem;
  box-shadow: var(--shadow);
}
.machine-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.75rem;
}
.machine-title {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
}
.machine-meta {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--fg-mute);
}

.steps {
  display: grid;
  gap: 0.4rem;
  margin-top: 0.9rem;
}
.step {
  display: grid;
  grid-template-columns: 2.2rem 1fr auto;
  align-items: center;
  gap: 0.7rem;
  padding: 0.55rem 0.7rem;
  border-radius: 10px;
  border: 1px solid transparent;
  transition: background 200ms var(--ease), border-color 200ms var(--ease);
}
.step.is-on {
  background: var(--rust-soft);
  border-color: rgba(217, 56, 30, 0.22);
}
.step-n {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 700;
  color: var(--fg-mute);
}
.step.is-on .step-n { color: var(--rust); }
.step-name {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 0.9rem;
  letter-spacing: -0.02em;
}
.step-note {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--fg-mute);
}

.scoreboard {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.5rem;
  margin-top: 0.9rem;
  padding-top: 0.9rem;
  border-top: 1px solid var(--border);
}
.stat {
  background: var(--subtle);
  border-radius: 10px;
  padding: 0.7rem 0.75rem;
}
.stat b {
  display: block;
  font-family: var(--font-mono);
  font-size: 1.05rem;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.03em;
}
.stat span {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--fg-mute);
}

.ticker {
  overflow: hidden;
  border-bottom: 1px solid var(--border);
  background: var(--subtle);
}
.ticker-track {
  display: flex;
  gap: 2.5rem;
  width: max-content;
  padding: 0.7rem 0;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink-700);
  animation: marquee 42s linear infinite;
}
.ticker b { color: var(--rust); margin-right: 0.45rem; }
@keyframes marquee {
  from { transform: translateX(0); }
  to { transform: translateX(-50%); }
}

.section {
  padding: var(--section) 0;
  border-bottom: 1px solid var(--border);
}
.section-kicker {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--rust);
}
.section h2 {
  margin: 0.55rem 0 0;
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 1.15rem + 1.4vw, 2.2rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.25;
  text-wrap: balance;
  max-width: 22em;
}
.section-lead {
  margin: 1rem 0 0;
  max-width: 42rem;
  color: var(--fg-2);
  font-size: 1.02rem;
  text-wrap: pretty;
}

.two-col {
  display: grid;
  gap: 1.5rem;
  margin-top: 2.4rem;
}
@media (min-width: 860px) {
  .two-col.eq { grid-template-columns: 1fr 1fr; }
  .two-col.split { grid-template-columns: 1.15fr 0.85fr; }
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.35rem 1.4rem;
  box-shadow: var(--shadow);
}
.card h3 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.15rem;
  letter-spacing: -0.02em;
}
.card p { margin: 0.55rem 0 0; color: var(--fg-2); }
.card ul {
  margin: 0.7rem 0 0;
  padding: 0 0 0 1.1rem;
  color: var(--fg-2);
}
.card li + li { margin-top: 0.3rem; }

.not-list {
  display: grid;
  gap: 0.55rem;
  margin-top: 1rem;
}
.not-item {
  display: flex;
  gap: 0.7rem;
  align-items: flex-start;
  padding: 0.7rem 0.8rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--paper-50);
}
.not-item strong {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--rust);
  min-width: 3.4rem;
  padding-top: 0.2rem;
}

.layers {
  display: grid;
  gap: 0;
  margin-top: 2rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--surface);
}
.layer {
  display: grid;
  grid-template-columns: 7.5rem 1fr;
  gap: 1rem;
  padding: 1rem 1.15rem;
  border-top: 1px solid var(--border);
}
.layer:first-child { border-top: 0; }
.layer-id {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--rust);
}
.layer h3 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1rem;
}
.layer p { margin: 0.2rem 0 0; color: var(--fg-2); font-size: 0.9rem; }
.layer code {
  font-size: 0.78rem;
  background: var(--subtle);
  padding: 0.05rem 0.35rem;
  border-radius: 4px;
}

@media (max-width: 640px) {
  .layer { grid-template-columns: 1fr; gap: 0.25rem; }
}

.invariants {
  display: grid;
  gap: 0.7rem;
  margin-top: 1.8rem;
}
@media (min-width: 720px) {
  .invariants { grid-template-columns: 1fr 1fr; }
}
.inv {
  display: grid;
  grid-template-columns: 2.4rem 1fr;
  gap: 0.7rem;
  padding: 0.95rem 1rem;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--surface);
}
.inv b {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--rust);
}
.inv p { margin: 0; color: var(--fg-2); font-size: 0.9rem; }

.timeline {
  margin-top: 2rem;
  display: grid;
  gap: 0;
  border-left: 2px solid var(--paper-300);
  padding-left: 1.4rem;
}
.tl {
  position: relative;
  padding: 0 0 1.6rem;
}
.tl::before {
  content: "";
  position: absolute;
  left: -1.55rem;
  top: 0.35rem;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--rust);
  box-shadow: 0 0 0 4px var(--bg);
}
.tl .when {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--fg-mute);
}
.tl h3 {
  margin: 0.15rem 0 0;
  font-family: var(--font-display);
  font-size: 1.15rem;
}
.tl p { margin: 0.3rem 0 0; color: var(--fg-2); max-width: 46rem; }

.uses {
  display: grid;
  gap: 0.85rem;
  margin-top: 2rem;
}
@media (min-width: 760px) {
  .uses { grid-template-columns: 1fr 1fr; }
}
@media (min-width: 1100px) {
  .uses { grid-template-columns: 1fr 1fr 1fr; }
}
.use {
  padding: 1.2rem 1.25rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: var(--surface);
  min-height: 100%;
}
.use .n {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--rust);
  letter-spacing: 0.08em;
}
.use h3 {
  margin: 0.35rem 0 0;
  font-family: var(--font-display);
  font-size: 1.08rem;
  letter-spacing: -0.02em;
}
.use p { margin: 0.45rem 0 0; color: var(--fg-2); }

.formula {
  margin-top: 1.4rem;
  background: var(--ink-950);
  color: var(--paper-50);
  border-radius: var(--radius-lg);
  padding: 1.2rem 1.3rem;
  overflow-x: auto;
}
.formula pre {
  margin: 0;
  font-size: 0.78rem;
  line-height: 1.65;
  white-space: pre;
}
.formula .c { color: #ff8a74; }

.example {
  margin-top: 1.2rem;
}
.example-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 0.45rem;
}
.example h3 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.05rem;
}
.copy {
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.2rem 0.7rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 700;
  background: var(--paper-50);
}
.copy:hover { border-color: var(--ink-950); }
.copy.is-ok { color: var(--emerald); border-color: var(--emerald); }

pre.cli {
  margin: 0;
  padding: 1rem 1.1rem;
  background: var(--ink-950);
  color: #e8e6df;
  border-radius: 12px;
  overflow-x: auto;
  font-size: 0.78rem;
  line-height: 1.6;
}
pre.cli .c { color: #8c9288; }
pre.cli .g { color: #7dcea0; }

.tools {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: 1rem;
}
.tool {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  border: 1px solid var(--border);
  background: var(--subtle);
  border-radius: 999px;
  padding: 0.28rem 0.7rem;
}

.stack-grid {
  display: grid;
  gap: 0.8rem;
  margin-top: 1.8rem;
}
@media (min-width: 720px) {
  .stack-grid { grid-template-columns: 1fr 1fr 1fr; }
}
.stack-item h3 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.05rem;
}
.stack-item p { margin: 0.4rem 0 0; color: var(--fg-2); }

.repo-box {
  margin-top: 1.8rem;
  display: grid;
  gap: 1rem;
  padding: 1.4rem 1.5rem;
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  background: var(--surface);
  box-shadow: var(--shadow);
}
@media (min-width: 800px) {
  .repo-box { grid-template-columns: 1fr auto; align-items: center; }
}
.repo-box h3 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.25rem;
}
.repo-box p { margin: 0.35rem 0 0; color: var(--fg-2); }
.docs {
  display: grid;
  gap: 0.55rem;
  margin-top: 1.4rem;
}
.doc {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 1rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  text-decoration: none;
  background: var(--paper-50);
  transition: border-color 150ms var(--ease);
}
.doc:hover { border-color: var(--ink-950); }
.doc b { font-family: var(--font-display); }
.doc span {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--fg-mute);
  white-space: nowrap;
}

.status {
  background: var(--ink-950);
  color: var(--paper-50);
  border-bottom: 0;
}
.status h2 { color: var(--paper-50); }
.status .section-lead { color: var(--ink-300); }
.status-grid {
  display: grid;
  gap: 0.8rem;
  margin-top: 2rem;
}
@media (min-width: 800px) {
  .status-grid { grid-template-columns: 1fr 1fr; }
}
.status .card {
  background: #181a18;
  border-color: var(--line-dark);
  color: var(--paper-50);
}
.status .card p { color: var(--ink-300); }
.ok { color: #7dcea0; }
.warn { color: #ffb088; }

.footer {
  background: var(--ink-950);
  color: var(--paper-50);
  padding: 2.5rem 0 2rem;
}
.footer-row {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1.2rem;
  align-items: flex-start;
}
.footer a { color: var(--paper-50); }
.footer .mute { color: var(--ink-300); font-size: 0.85rem; }
.footer-brand {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  text-decoration: none;
}

:focus-visible {
  outline: 2px solid var(--rust);
  outline-offset: 3px;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .ticker-track, .dot::after { animation: none; }
}