:root {
  --bg: #fbfbf9;
  --surface: #ffffff;
  --surface-soft: #f5f4f0;
  --text: #1d1d1b;
  --muted: #66655f;
  --line: #e8e6df;
  --line-strong: #d5d2c8;
  --chip: #efeee8;
  --shadow: 0 12px 30px rgba(17, 17, 17, 0.04);
  --radius-xl: 28px;
  --radius-lg: 22px;
  --radius-md: 16px;
  --radius-sm: 12px;
  --max-width: 1120px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Apple SD Gothic Neo", "Noto Sans KR", "Malgun Gothic", sans-serif;
  line-height: 1.7;
}

img,
svg {
  display: block;
  max-width: 100%;
}

a,
button {
  color: inherit;
}

strong {
  font-weight: 700;
}

.top-progress {
  position: fixed;
  inset: 0 auto auto 0;
  width: 0;
  height: 3px;
  background: #1d1d1b;
  z-index: 60;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(14px);
  background: rgba(251, 251, 249, 0.82);
  border-bottom: 1px solid rgba(232, 230, 223, 0.86);
}

.header-inner {
  width: min(var(--max-width), calc(100% - 32px));
  min-height: 72px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.brand {
  display: grid;
  gap: 2px;
  text-decoration: none;
  white-space: nowrap;
}

.brand-label {
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
}

.brand-title {
  font-size: 15px;
  font-weight: 700;
  letter-spacing: -0.03em;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 8px;
  overflow-x: auto;
}

.nav-link {
  text-decoration: none;
  color: var(--muted);
  font-size: 14px;
  padding: 8px 12px;
  border-radius: 999px;
  white-space: nowrap;
  transition: background 0.2s ease, color 0.2s ease;
}

.nav-link:hover,
.nav-link.is-active {
  background: var(--surface-soft);
  color: var(--text);
}

.page {
  width: min(var(--max-width), calc(100% - 32px));
  margin: 0 auto;
  padding: 42px 0 90px;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(320px, 0.85fr);
  gap: 28px;
  align-items: start;
  padding-top: 18px;
}

.page-path,
.section-kicker,
.panel-label,
.track-map-label {
  margin: 0 0 12px;
  color: var(--muted);
  font-size: 13px;
  letter-spacing: -0.01em;
}

.hero h1 {
  margin: 0;
  font-size: clamp(2.45rem, 6vw, 4.85rem);
  line-height: 1.08;
  letter-spacing: -0.055em;
}

.lead {
  margin: 22px 0 0;
  max-width: 700px;
  font-size: 17px;
  color: #32312d;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 22px;
}

.meta-chip,
.badge {
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--chip);
  font-size: 13px;
  color: #45443f;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 28px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0 18px;
  border-radius: 999px;
  border: 1px solid var(--line-strong);
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
  transition: transform 0.18s ease, background 0.18s ease, border-color 0.18s ease;
}

.button:hover {
  transform: translateY(-1px);
}

.button-primary {
  background: #1d1d1b;
  border-color: #1d1d1b;
  color: #ffffff;
}

.button-secondary {
  background: var(--surface);
}

.note-block,
.panel,
.mini-card,
.point-card,
.diagram-card,
.track-card,
.callout,
.criteria-card,
.footer,
.closing-note {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}

.note-block {
  margin-top: 24px;
  padding: 18px 20px;
}

.note-block strong,
.callout strong,
.closing-note strong {
  display: block;
  margin-bottom: 6px;
  font-size: 14px;
}

.note-block p,
.callout p,
.closing-note p {
  margin: 0;
  color: var(--muted);
}

.hero-side {
  display: grid;
  gap: 18px;
}

.panel {
  padding: 18px;
}

.panel-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  margin-bottom: 16px;
}

.panel-label {
  margin: 0;
}

.panel-meta {
  color: var(--muted);
  font-size: 13px;
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.stat-card {
  padding: 16px;
  border-radius: var(--radius-md);
  background: var(--surface-soft);
  border: 1px solid var(--line);
}

.stat-value {
  margin: 0;
  font-size: 28px;
  font-weight: 700;
  letter-spacing: -0.05em;
}

.stat-label {
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 13px;
}

.file-list {
  display: grid;
  gap: 12px;
}

.file-item {
  display: block;
  padding: 14px 15px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--surface-soft);
  text-decoration: none;
  transition: border-color 0.18s ease, transform 0.18s ease;
}

.file-item:hover {
  border-color: var(--line-strong);
  transform: translateY(-1px);
}

.file-name {
  margin: 0;
  font-size: 14px;
  font-weight: 600;
  word-break: break-word;
}

.file-meta {
  margin: 6px 0 0;
  color: var(--muted);
  font-size: 13px;
}

.section {
  margin-top: 104px;
}

.section-heading {
  max-width: 820px;
  margin-bottom: 28px;
}

.section-heading h2 {
  margin: 0;
  font-size: clamp(1.9rem, 4vw, 2.8rem);
  line-height: 1.15;
  letter-spacing: -0.045em;
}

.section-desc {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 16px;
}

.summary-grid,
.direct-grid,
.criteria-grid {
  display: grid;
  gap: 16px;
}

.summary-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.direct-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.criteria-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.mini-card,
.point-card,
.track-card,
.criteria-card {
  padding: 22px;
}

.mini-title,
.point-title,
.criteria-title,
.track-name,
.track-map-card h3 {
  margin: 0;
  font-weight: 700;
  font-size: 18px;
  letter-spacing: -0.03em;
}

.mini-body,
.point-body,
.track-summary,
.track-map-card p {
  margin: 10px 0 0;
  color: var(--muted);
}

.point-card {
  position: relative;
  overflow: hidden;
}

.point-card::before {
  content: "";
  position: absolute;
  inset: 0 auto 0 0;
  width: 4px;
  background: #1d1d1b;
  opacity: 0.08;
}

.diagram-card {
  padding: 24px;
}

.pipeline-strip {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 42px minmax(0, 1fr) 42px minmax(0, 1fr) 42px minmax(0, 1fr) 42px minmax(0, 1fr);
  gap: 0;
  align-items: stretch;
}

.pipeline-node {
  min-height: 148px;
  padding: 20px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--surface-soft);
}

.pipeline-node-strong {
  background: #f1efe8;
}

.pipeline-title {
  margin: 0;
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.03em;
}

.pipeline-body {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.65;
}

.pipeline-arrow {
  position: relative;
  align-self: center;
  justify-self: center;
  width: 100%;
  height: 2px;
  background: var(--line-strong);
}

.pipeline-arrow::after {
  content: "";
  position: absolute;
  right: 0;
  top: 50%;
  width: 9px;
  height: 9px;
  border-top: 2px solid var(--line-strong);
  border-right: 2px solid var(--line-strong);
  transform: translateY(-50%) rotate(45deg);
}

.track-map {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin-top: 20px;
}

.track-map-card {
  padding: 20px;
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
  background: var(--surface);
}

.track-map-label {
  margin-bottom: 8px;
}

.track-map-card ul {
  margin: 14px 0 0;
  padding-left: 18px;
}

.track-map-card li + li {
  margin-top: 6px;
}

.diagram-footnote {
  margin-top: 18px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
  color: var(--muted);
}

.tracks-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.track-top {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.badge-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.track-list {
  margin: 16px 0 0;
  padding-left: 18px;
  color: #3a3935;
}

.track-list li + li {
  margin-top: 8px;
}

.track-memo {
  margin: 16px 0 0;
  padding: 12px 14px;
  border-radius: 14px;
  background: var(--surface-soft);
  color: #4f4d48;
  font-size: 14px;
}

.code-note {
  margin: 18px 0 0;
  padding: 16px;
  border-radius: var(--radius-md);
  background: #171717;
  color: #f4f4f1;
  border: 1px solid #2b2b2b;
  overflow-x: auto;
  font-size: 13px;
  line-height: 1.6;
}

.callout {
  padding: 18px 20px;
  margin-bottom: 18px;
}

.timeline-root {
  display: grid;
  gap: 28px;
}

.timeline-group {
  display: grid;
  gap: 16px;
}

.timeline-date {
  font-size: 22px;
  font-weight: 700;
  letter-spacing: -0.03em;
}

.timeline-list {
  display: grid;
  gap: 14px;
}

.commit-card {
  display: grid;
  grid-template-columns: 132px minmax(0, 1fr);
  gap: 18px;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  background: var(--surface);
  box-shadow: var(--shadow);
}

.commit-left {
  padding-right: 8px;
  border-right: 1px solid var(--line);
}

.commit-sha {
  display: inline-flex;
  align-items: center;
  min-height: 28px;
  padding: 0 10px;
  border-radius: 999px;
  background: var(--surface-soft);
  border: 1px solid var(--line);
  font-size: 12px;
  font-weight: 700;
}

.commit-file {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.5;
  word-break: break-word;
}

.commit-title {
  margin: 0;
  font-size: 19px;
  font-weight: 700;
  letter-spacing: -0.03em;
}

.commit-desc {
  margin: 6px 0 0;
  color: var(--muted);
}

.commit-points {
  margin: 12px 0 0;
  padding-left: 18px;
}

.commit-points li + li {
  margin-top: 6px;
}

.diff-block {
  margin-top: 14px;
  padding-top: 14px;
  border-top: 1px solid var(--line);
}

.diff-label {
  margin: 0 0 10px;
  color: var(--muted);
  font-size: 13px;
}

.diff-row {
  display: grid;
  grid-template-columns: 46px minmax(0, 1fr) 86px;
  align-items: center;
  gap: 10px;
}

.diff-row + .diff-row {
  margin-top: 8px;
}

.diff-kind {
  font-size: 12px;
  color: var(--muted);
}

.diff-track {
  height: 10px;
  border-radius: 999px;
  background: #efeee9;
  overflow: hidden;
  border: 1px solid var(--line);
}

.diff-fill {
  display: block;
  height: 100%;
  border-radius: inherit;
  background: #1d1d1b;
}

.diff-fill-light {
  background: #8a8780;
}

.diff-value {
  text-align: right;
  font-size: 12px;
  color: var(--muted);
}

.criteria-card ul {
  margin: 12px 0 0;
  padding-left: 18px;
}

.criteria-card li + li {
  margin-top: 8px;
}

.criteria-card-highlight {
  background: #f6f5f1;
}

.closing-note {
  margin-top: 18px;
  padding: 18px 20px;
}

.footer {
  margin-top: 104px;
  padding: 26px;
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}

.footer-title {
  margin: 0;
  font-size: 20px;
  font-weight: 700;
  letter-spacing: -0.03em;
}

.footer-copy {
  margin: 8px 0 0;
  color: var(--muted);
  max-width: 720px;
}

.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.65s ease, transform 0.65s ease;
}

.reveal.is-visible {
  opacity: 1;
  transform: translateY(0);
}

@media (max-width: 1180px) {
  .pipeline-strip {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 14px;
  }

  .pipeline-arrow {
    display: none;
  }
}

@media (max-width: 1080px) {
  .hero,
  .tracks-grid,
  .track-map {
    grid-template-columns: 1fr;
  }

  .summary-grid,
  .direct-grid,
  .criteria-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 780px) {
  .page,
  .header-inner {
    width: min(var(--max-width), calc(100% - 22px));
  }

  .page {
    padding-top: 32px;
  }

  .section {
    margin-top: 76px;
  }

  .summary-grid,
  .direct-grid,
  .criteria-grid,
  .stat-grid,
  .pipeline-strip {
    grid-template-columns: 1fr;
  }

  .commit-card {
    grid-template-columns: 1fr;
  }

  .commit-left {
    border-right: 0;
    border-bottom: 1px solid var(--line);
    padding-right: 0;
    padding-bottom: 12px;
  }

  .footer-inner {
    flex-direction: column;
    align-items: flex-start;
  }

  .diagram-card {
    padding: 16px;
  }
}