:root {
  --text: #1a1a1a;
  --muted: #555;
  --faint: #777;
  --border: #ddd;
  --fill: #f0f0f0;
  --fill-2: #fafafa;
  --accent: #0056b3;
  --accent-fill: #eef3fa;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --header-h: 52px;
  --sidebar-w: 240px;
  --toc-w: 244px;
}

* {
  box-sizing: border-box;
}
html {
  scroll-behavior: smooth;
  overscroll-behavior-y: none;
}

body {
  margin: 0;
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.6;
  color: var(--text);
  background: #fff;
  overscroll-behavior-y: none;
}
a {
  color: var(--accent);
}
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  height: var(--header-h);
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 0 20px;
  background: #fff;
  border-bottom: 1px solid var(--border);
}
.brand {
  display: flex;
  align-items: center;
  gap: 9px;
  text-decoration: none;
}
.brand .mark {
  font-family: var(--mono);
  font-size: 12px;
  font-weight: 600;
  color: var(--text);
  border: 1px solid var(--border);
  padding: 2px 6px;
  border-radius: 3px;
  background: var(--fill-2);
}
.brand .name {
  font-weight: 600;
  font-size: 15px;
  letter-spacing: -0.01em;
  color: var(--text);
}
.brand .name span {
  color: var(--faint);
  font-weight: 400;
}

.breadcrumb {
  font-family: var(--mono);
  font-size: 12.5px;
  color: var(--faint);
  display: flex;
  align-items: center;
  gap: 6px;
}
.breadcrumb .here {
  color: var(--text);
}

.header-spacer {
  flex: 1;
}

.search {
  display: flex;
  align-items: center;
  gap: 8px;
  height: 32px;
  padding: 0 10px;
  min-width: 210px;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: #fff;
  color: var(--faint);
  font-size: 13.5px;
  font-family: var(--sans);
  text-align: left;
  cursor: pointer;
}
.search:hover {
  border-color: #bbb;
  color: var(--muted);
}
.search .kbd {
  margin-left: auto;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--faint);
  border: 1px solid var(--border);
  border-radius: 3px;
  padding: 1px 5px;
  background: var(--fill-2);
}

.menu-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: #fff;
  cursor: pointer;
  color: var(--text);
}
.menu-toggle svg {
  width: 18px;
  height: 18px;
}

.layout {
  display: grid;
  grid-template-columns: var(--sidebar-w) minmax(0, 1fr) var(--toc-w);
  max-width: 1320px;
  margin: 0 auto;
  align-items: start;
}

.sidebar {
  position: sticky;
  top: var(--header-h);
  height: calc(100vh - var(--header-h));
  overflow-y: auto;
  padding: 24px 14px 48px 20px;
  border-right: 1px solid var(--border);
}
.nav-group {
  margin-bottom: 22px;
}
.nav-group > .label {
  font-family: var(--mono);
  font-size: 11.5px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--faint);
  margin: 0 0 6px 8px;
}
.nav-group ul {
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-group li {
  margin: 1px 0;
}
.nav-group a {
  display: block;
  padding: 5px 10px;
  border-radius: 4px;
  color: #444;
  font-size: 14.5px;
  text-decoration: none;
  border-left: 2px solid transparent;
}
.nav-group a:hover {
  background: var(--fill-2);
  color: var(--text);
}
.nav-group a.active {
  background: var(--accent-fill);
  color: var(--accent);
  font-weight: 600;
  border-radius: 4px;
}

.content {
  min-width: 0;
  padding: 28px 40px 80px;
}
.article {
  max-width: 780px;
  margin: 0 auto;
}

.toc {
  position: sticky;
  top: calc(var(--header-h) + 28px);
  max-height: calc(100vh - var(--header-h) - 56px);
  overflow-y: auto;
  margin: 28px 20px 0 0;
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 16px 18px;
  background: var(--fill-2);
  font-size: 14px;
}
.toc b {
  display: block;
  margin-bottom: 8px;
  font-size: 15px;
}
.toc ol {
  margin: 0;
  padding-left: 24px;
}
.toc li {
  margin: 4px 0;
}
.toc a {
  text-decoration: none;
  color: var(--accent);
}
.toc a:hover {
  text-decoration: underline;
}
.toc code {
  font-family: var(--mono);
  font-size: 0.85em;
  background: var(--fill);
  padding: 1px 5px;
  border-radius: 3px;
}

.overlay {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 30;
  background: rgba(0, 0, 0, 0.28);
}

h1 {
  font-size: 30px;
  line-height: 1.2;
  margin: 0 0 8px;
}
h2 {
  font-size: 24px;
  margin: 48px 0 4px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  scroll-margin-top: calc(var(--header-h) + 12px);
}
h3 {
  font-size: 19px;
  margin: 32px 0 4px;
  scroll-margin-top: calc(var(--header-h) + 12px);
}
h4 {
  font-size: 16px;
  margin: 22px 0 4px;
}
p {
  margin: 12px 0;
}
.lead {
  color: var(--muted);
  margin: 6px 0 20px;
}
.subtitle {
  color: var(--muted);
  margin: 0 0 24px;
}
strong {
  font-weight: 600;
}
em.term {
  font-style: normal;
  font-weight: 600;
}

.article code {
  font-family: var(--mono);
  font-size: 0.88em;
  background: var(--fill);
  padding: 1px 5px;
  border-radius: 3px;
}
.article a {
  color: var(--accent);
}
hr {
  border: 0;
  border-top: 1px solid var(--border);
  margin: 40px 0;
}

figure.code {
  margin: 16px 0;
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
}
figure.code figcaption {
  background: var(--fill);
  padding: 6px 12px;
  font-size: 13px;
  color: var(--muted);
  border-bottom: 1px solid var(--border);
}
figure.code figcaption .dot,
figure.code figcaption .f {
  display: none;
}
figure.code figcaption b {
  font-weight: 600;
  color: #333;
}
pre {
  margin: 0;
  background: #f7f7f7;
  padding: 12px 14px;
  overflow-x: auto;
}
pre code {
  font-family: var(--mono);
  font-size: 13.5px;
  line-height: 1.5;
  background: none;
  padding: 0;
  color: var(--text);
}

.note,
.warn,
.key,
.analogy {
  border-left: 3px solid #999;
  padding: 2px 0 2px 14px;
  margin: 16px 0;
  font-size: 16px;
  color: #333;
}
.note {
  border-left-color: #c99a2e;
}
.warn {
  border-left-color: #c0392b;
}
.key {
  border-left-color: #2c6fbb;
}
.analogy {
  border-left-color: #888;
  font-style: italic;
}
.note strong,
.warn strong,
.key strong {
  display: block;
  font-size: 14px;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  margin-bottom: 2px;
}
.note strong {
  color: #8a6a1a;
}
.warn strong {
  color: #a3281a;
}
.key strong {
  color: #1f5691;
}
.note p,
.warn p,
.key p,
.analogy p {
  margin: 4px 0 0;
}
.analogy::before {
  content: "Analogy — ";
  font-style: normal;
  font-weight: 600;
  color: var(--muted);
}
.analogy.pillar::before {
  content: "Analogy — ";
}

.tbl {
  margin: 16px 0;
  overflow-x: auto;
}
table {
  border-collapse: collapse;
  width: 100%;
  font-size: 15px;
}
th,
td {
  text-align: left;
  padding: 8px 12px;
  border: 1px solid var(--border);
  vertical-align: top;
}
th {
  background: var(--fill);
  font-weight: 600;
}
.yes {
  color: #1a7a3e;
  font-weight: 600;
}
.no {
  color: #b02a20;
  font-weight: 600;
}

.pillar-grid {
  margin: 16px 0;
  padding: 0;
  list-style: none;
}
.pcard {
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 10px 14px;
  margin: 8px 0;
}
.pcard .pn {
  font-size: 12px;
  color: var(--faint);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.pcard h4 {
  margin: 2px 0 4px;
  font-size: 16px;
}
.pcard p {
  margin: 0;
  font-size: 15px;
  color: #444;
}

.dd {
  margin: 16px 0;
}
.dd > div {
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 10px 14px;
  margin: 8px 0;
  font-size: 15px;
}
.dd h5 {
  margin: 0 0 4px;
  font-size: 14px;
}
.dd .do h5 {
  color: #1a7a3e;
}
.dd .dont h5 {
  color: #b02a20;
}
.dd ul {
  margin: 0;
  padding-left: 18px;
}

ul.clean {
  padding-left: 22px;
}
ul.clean li {
  margin: 5px 0;
}

.qa {
  margin: 16px 0;
}
.qa .q {
  font-weight: 600;
  margin: 0 0 2px;
}
.qa .a {
  margin: 0;
  color: #444;
}

.divider {
  margin: 44px 0 0;
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--faint);
}
.num {
  color: var(--faint);
  font-weight: 400;
}

footer.doc-footer {
  margin-top: 56px;
  padding-top: 16px;
  border-top: 1px solid var(--border);
  color: var(--faint);
  font-size: 14px;
}

.home-main {
  max-width: 920px;
  margin: 0 auto;
  padding: 56px 24px 96px;
}
.home {
  max-width: 820px;
  margin: 0 auto;
  text-align: center;
}
.home-logo {
  width: 76px;
  height: 76px;
  border-radius: 16px;
  display: block;
  margin: 0 auto 16px;
}
.home h1 {
  font-size: 32px;
  margin: 0 0 36px;
  letter-spacing: -0.02em;
}
.home .subtitle {
  margin-bottom: 32px;
}
.topic-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 16px;
  text-align: left;
}
.topic-card {
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 16px 18px;
}
.topic-card h3 {
  margin: 0 0 8px;
  font-size: 17px;
}
.topic-card ul {
  list-style: none;
  margin: 0;
  padding: 0;
}
.topic-card li {
  margin: 4px 0;
  font-size: 15px;
}
.topic-card a {
  text-decoration: none;
}
.topic-card a:hover {
  text-decoration: underline;
}
.topic-card .empty {
  color: var(--faint);
  font-size: 14px;
  font-style: italic;
}

@media (max-width: 1080px) {
  .layout {
    grid-template-columns: var(--sidebar-w) minmax(0, 1fr);
  }
  .toc {
    display: none;
  }
}
@media (max-width: 840px) {
  .layout {
    grid-template-columns: minmax(0, 1fr);
  }
  .menu-toggle {
    display: flex;
  }
  .search {
    display: none;
  }
  .sidebar {
    position: fixed;
    top: var(--header-h);
    left: 0;
    bottom: 0;
    width: 274px;
    height: auto;
    z-index: 35;
    background: #fff;
    overflow-y: auto;
    overscroll-behavior: contain;
    -webkit-overflow-scrolling: touch;
    padding: 16px 14px 32px 20px;
    border-right: 1px solid var(--border);
    transform: translateX(-100%);
    transition: transform 0.2s ease;
  }
  body.nav-open {
    overflow: hidden;
  }
  body.nav-open .sidebar {
    transform: translateX(0);
  }
  body.nav-open .overlay {
    display: block;
    top: var(--header-h);
  }
  .content {
    padding: 24px 22px 64px;
  }
}
@media (max-width: 480px) {
  body {
    font-size: 16px;
  }
  h1 {
    font-size: 26px;
  }
  h2 {
    font-size: 21px;
  }
  .content {
    padding: 20px 16px 56px;
  }
  .breadcrumb .crumb-hide {
    display: none;
  }
}
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  .sidebar {
    transition: none;
  }
}

.brand .logo {
  width: 26px;
  height: 26px;
  border-radius: 6px;
  display: block;
}

.is-home .menu-toggle,
.is-home .breadcrumb {
  display: none;
}

.search-modal {
  position: fixed;
  inset: 0;
  z-index: 60;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 12vh 16px 16px;
  background: rgba(0, 0, 0, 0.32);
}
.search-modal[hidden] {
  display: none;
}
.search-panel {
  width: min(560px, 100%);
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: 0 14px 44px rgba(0, 0, 0, 0.18);
  overflow: hidden;
}
.search-input {
  width: 100%;
  border: 0;
  border-bottom: 1px solid var(--border);
  padding: 14px 16px;
  font-size: 16px;
  font-family: var(--sans);
  color: var(--text);
  outline: none;
}
.search-results {
  list-style: none;
  margin: 0;
  padding: 6px;
  max-height: 54vh;
  overflow-y: auto;
}
.search-results li {
  margin: 0;
}
.search-results a {
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 8px 12px;
  border-radius: 5px;
  text-decoration: none;
  color: var(--text);
}
.search-results a:hover,
.search-results a.active {
  background: var(--accent-fill);
}
.search-results .r-label {
  font-size: 14.5px;
  font-weight: 500;
}
.search-results .r-sub {
  font-size: 12px;
  color: var(--faint);
}
.search-empty {
  padding: 18px;
  margin: 0;
  text-align: center;
  color: var(--faint);
  font-size: 14px;
}