* { box-sizing: border-box; }
html { scroll-padding-top: 5rem; }
/* Dot grid matches the Kei console canvas (.kei-app): emerald dots, 16px pitch. */
body { margin: 0; background-color: var(--color-ground); background-image: radial-gradient(rgba(4, 120, 87, .16) .8px, transparent .8px); background-size: 16px 16px; color: var(--color-content); font: 16px/1.75 var(--font-sans); -webkit-font-smoothing: antialiased; }
a { color: var(--color-accent-text); text-underline-offset: .18em; }
a:hover { color: var(--color-accent-hover); }
[data-theme="dark"] a:hover { color: var(--color-content); }
:focus-visible { outline: 2px solid var(--color-accent-text); outline-offset: 2px; border-radius: 4px; }
.skip-link { position: absolute; left: -9999px; top: 0; padding: .6rem 1rem; background: var(--color-surface); }
.skip-link:focus { left: 1rem; z-index: 20; }

/* Header */
.site-header { position: sticky; top: 0; z-index: 10; display: flex; align-items: center; gap: .75rem; height: 3.5rem; padding: 0 clamp(1rem, 3vw, 2rem); border-bottom: 1px solid var(--color-line); background: var(--color-ground); }
.brand { display: flex; align-items: center; gap: .6rem; color: var(--color-content); font-weight: 600; letter-spacing: -.03em; text-decoration: none; }
.brand:hover { color: var(--color-content); }
.docs-label { text-decoration: none; padding: .1rem .55rem; border: 1px solid var(--color-line-strong); border-radius: 9999px; color: var(--color-muted); font: 500 .75rem/1.4 var(--font-mono); letter-spacing: .04em; }
.docs-label:hover { border-color: var(--color-accent-text); color: var(--color-accent-text); }
.header-spacer { flex: 1; }
.header-link { padding: 0 .5rem; color: var(--color-muted); font-size: .875rem; font-weight: 500; text-decoration: none; }
.header-link:hover { color: var(--color-accent-text); }
.icon-link, .theme-toggle, .nav-toggle { display: inline-flex; align-items: center; justify-content: center; min-width: 2.25rem; height: 2.25rem; padding: 0 .75rem; border: 1px solid var(--color-line); border-radius: 9999px; background: transparent; color: var(--color-muted); font: 500 .8rem var(--font-sans); cursor: pointer; text-decoration: none; }
.icon-link { padding: 0; }
.icon-link:hover, .theme-toggle:hover, .nav-toggle:hover { border-color: var(--color-line-strong); background: var(--color-surface-hover); color: var(--color-content); }
.nav-toggle { display: none; padding: 0; }
.nav-toggle span, .nav-toggle span::before, .nav-toggle span::after { display: block; width: 1rem; height: 2px; background: currentColor; content: ""; }
.nav-toggle span { position: relative; }
.nav-toggle span::before { position: absolute; top: -5px; }
.nav-toggle span::after { position: absolute; top: 5px; }

/* Three-column layout: nav, content, on this page */
.layout { display: grid; grid-template-columns: 16rem minmax(0, 1fr) 14rem; gap: 0 clamp(1.5rem, 3vw, 3rem); max-width: 84rem; margin: 0 auto; padding: 0 clamp(1rem, 3vw, 2rem); }
.sidebar { position: sticky; top: 3.5rem; align-self: start; max-height: calc(100vh - 3.5rem); overflow-y: auto; padding: 2rem 0; }
.nav-section { margin: 1.5rem 0 .4rem; color: var(--color-content); font-size: .8125rem; font-weight: 600; }
.nav-section:first-child { margin-top: 0; }
.sidebar ul { margin: 0; padding: 0; list-style: none; }
.sidebar li a { display: block; padding: .3rem .75rem; border-left: 1px solid var(--color-line); color: var(--color-muted); font-size: .875rem; line-height: 1.5; text-decoration: none; }
.sidebar li a:hover { border-left-color: var(--color-line-strong); color: var(--color-content); }
.sidebar li a[aria-current="page"] { border-left: 2px solid var(--color-accent-text); padding-left: calc(.75rem - 1px); color: var(--color-accent-text); font-weight: 500; }
.toc { position: sticky; top: 3.5rem; align-self: start; max-height: calc(100vh - 3.5rem); overflow-y: auto; padding: 2.5rem 0; font-size: .8125rem; }
.toc h2 { margin: 0 0 .6rem; color: var(--color-content); font-size: .8125rem; font-weight: 600; }
.toc ul { margin: 0; padding: 0; list-style: none; }
.toc a { display: block; padding: .22rem 0; color: var(--color-muted); line-height: 1.45; text-decoration: none; }
.toc a:hover { color: var(--color-accent-text); }
.toc-l3 a { padding-left: .9rem; }

/* Content */
.content { grid-column: 2; min-width: 0; padding: 2.5rem 0 3.5rem; }
.title-row { display: flex; justify-content: space-between; align-items: flex-start; gap: 1.5rem; margin-bottom: .75rem; max-width: 46rem; }
h1 { margin: 0; font-size: clamp(1.9rem, 4vw, 2.5rem); font-weight: 600; line-height: 1.15; letter-spacing: -.035em; }
.page-links { display: flex; flex: none; flex-direction: column; align-items: flex-end; gap: .1rem; margin-top: .5rem; }
.markdown-link { font-size: .8125rem; white-space: nowrap; }
.validated { margin: 0 0 1.5rem; color: var(--color-faint); font: 500 .75rem/1.5 var(--font-mono); }
.prose { max-width: 46rem; }
.prose > :first-child { margin-top: 0; }
.prose h2 { margin: 2.75rem 0 .75rem; padding-top: 1.75rem; border-top: 1px solid var(--color-line); font-size: 1.5rem; font-weight: 600; line-height: 1.25; letter-spacing: -.025em; }
.prose h3 { margin: 2rem 0 .5rem; font-size: 1.125rem; font-weight: 600; line-height: 1.35; }
.prose h4 { margin: 1.5rem 0 .4rem; font-size: 1rem; font-weight: 600; }
.prose p, .prose ul, .prose ol { margin: 0 0 1.1rem; }
.prose li + li { margin-top: .3rem; }
.prose strong { font-weight: 600; }
.anchor { margin-left: .4rem; color: var(--color-faint); font: 500 .8em var(--font-mono); text-decoration: none; opacity: 0; transition: opacity .12s; }
:is(h2, h3, h4):hover .anchor, .anchor:focus-visible { opacity: 1; }
.prose :not(pre) > code { padding: .12rem .35rem; border: 1px solid var(--color-line); border-radius: .3rem; background: var(--color-surface); font: 500 .85em var(--font-mono); overflow-wrap: anywhere; }
.prose table { display: block; margin: 0 0 1.25rem; width: 100%; overflow-x: auto; border-collapse: collapse; font-size: .9rem; }
.prose th, .prose td { padding: .55rem .75rem; border-bottom: 1px solid var(--color-line); text-align: left; vertical-align: top; }
.prose th { border-bottom-color: var(--color-line-strong); font-weight: 600; white-space: nowrap; }
.prose img { max-width: 100%; height: auto; }
.prose blockquote { margin: 1.25rem 0; padding: .1rem 1rem; border-left: 3px solid var(--color-line-strong); color: var(--color-muted); }
.prose blockquote > p { margin: .6rem 0; }
.prose .callout { border: 1px solid; border-radius: .75rem; color: var(--color-content); padding: .35rem 1.1rem; }
.callout-note { border-color: var(--kei-permit-line); background: var(--kei-permit-bg); }
.callout-note > p:first-child > strong:first-child { color: var(--kei-permit-ink); }
.callout-warning { border-color: var(--kei-deny-line); background: var(--kei-deny-bg); }
.callout-warning > p:first-child > strong:first-child { color: var(--kei-deny-ink); }

/* Code */
.code-block { margin: 1.25rem 0; border: 1px solid var(--color-line); border-radius: .75rem; background: var(--color-surface); overflow: hidden; }
.code-head { display: flex; align-items: center; justify-content: space-between; gap: 1rem; min-height: 2.25rem; padding: 0 .5rem 0 1rem; border-bottom: 1px solid var(--color-line); background: var(--color-surface-hover); }
.code-label { color: var(--color-faint); font: 500 .75rem var(--font-mono); letter-spacing: .02em; }
.code-label.is-file { color: var(--color-muted); }
.copy { padding: .2rem .6rem; border: 0; border-radius: 9999px; background: transparent; color: var(--color-muted); font: 500 .75rem var(--font-sans); cursor: pointer; }
.copy:hover { background: var(--color-line); color: var(--color-content); }
.no-js .copy, html:not(.js) .copy { display: none; }
.prose pre { margin: 0; overflow-x: auto; padding: 1rem; font: 500 .8125rem/1.65 var(--font-mono); tab-size: 2; }
.prose pre code { padding: 0; border: 0; background: none; font: inherit; overflow-wrap: normal; }
.tok-c { color: var(--code-comment); font-style: italic; }
.tok-s { color: var(--code-string); }
.tok-k { color: var(--code-keyword); font-weight: 600; }
.tok-f { color: var(--code-flag); }
.tok-v, .tok-p { color: var(--code-variable); }
.tok-n { color: var(--code-number); }

/* Prev / next */
.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; max-width: 46rem; margin-top: 3.5rem; }
.pager a { display: flex; flex-direction: column; gap: .15rem; padding: .9rem 1.1rem; border: 1px solid var(--color-line); border-radius: .75rem; text-decoration: none; }
.pager a:hover { border-color: var(--color-accent-text); }
.pager-next { grid-column: 2; align-items: flex-end; text-align: right; }
.pager-label { color: var(--color-faint); font-size: .75rem; }
.pager-title { color: var(--color-accent-text); font-weight: 500; }
.footer { max-width: 46rem; margin-top: 3rem; padding-top: 1rem; border-top: 1px solid var(--color-line); color: var(--color-faint); font-size: .8125rem; }

/* Home */
.home-intro { max-width: 40rem; margin: 1rem 0 0; color: var(--color-muted); font-size: 1.25rem; line-height: 1.6; }
.content > section { margin-top: 2.5rem; }
.content > section > h2 { margin: 0 0 .9rem; font-size: 1.125rem; font-weight: 600; }
.home-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(15rem, 1fr)); gap: .75rem; }
.home-card { display: flex; flex-direction: column; gap: .2rem; padding: 1rem 1.1rem; border: 1px solid var(--color-line); border-radius: .75rem; background: var(--color-surface); color: var(--color-content); text-decoration: none; }
.home-card:hover { border-color: var(--color-accent-text); color: var(--color-content); }
.home-card strong { font-weight: 500; line-height: 1.4; }
.home-card span { color: var(--color-faint); font: 500 .75rem var(--font-mono); }

@media (max-width: 1100px) {
  .layout { grid-template-columns: 15rem minmax(0, 1fr); }
  .toc { display: none; }
}
@media (max-width: 800px) {
  .nav-toggle { display: inline-flex; }
  .wordmark { display: none; }
  .site-header { gap: .5rem; padding: 0 1rem; }
  .header-link { padding: 0 .25rem; }
  .layout { display: block; padding: 0 1rem; }
  html.js .sidebar { display: none; }
  html.js body.nav-open .sidebar { display: block; position: fixed; inset: 3.5rem 0 0; z-index: 9; max-height: none; padding: 1rem 1.25rem 2rem; background: var(--color-ground); }
  body.nav-open { overflow: hidden; }
  .sidebar { position: static; max-height: none; padding: 1rem 0; border-bottom: 1px solid var(--color-line); }
  .content { padding: 1.5rem 0 3rem; }
  .title-row { display: block; }
  .page-links { flex-direction: row; gap: 1rem; margin-top: .6rem; }
  .pager { grid-template-columns: 1fr; }
  .pager-next { grid-column: 1; }
  .prose h2 { font-size: 1.35rem; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }