/* The whole theme. One stylesheet, no build step, no preprocessor: the site
   is prose, and the layout it needs is a header, a sidebar, a column of text
   and a rail. Colours are declared once as custom properties and swapped by
   the reader's light/dark preference. */

:root {
  color-scheme: light dark;

  --bg: #fdfdfc;
  --bg-soft: #f2f1ee;
  --fg: #1f1f1d;
  --fg-soft: #5c5b56;
  --rule: #e0deda;
  --link: #1b5e8a;
  --accent: #b7541a;

  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", Helvetica, Arial, sans-serif;
  /* One column width, shared by the header and the prose, so the page has a
     single left edge from the wordmark down. */
  --measure: 40rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #16171a;
    --bg-soft: #1e2024;
    --fg: #e6e5e1;
    --fg-soft: #a3a29c;
    --rule: #2e3136;
    --link: #79b8dd;
    --accent: #e0904f;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.6 var(--sans);
}

a { color: var(--link); }

/* Header ------------------------------------------------------------- */

header {
  display: flex;
  align-items: baseline;
  flex-wrap: wrap;
  /* A row gap as well as a column one: on a narrow phone the header wraps,
     and every item in it has line-height 1. */
  gap: 0.35rem 1rem;
  padding: 0.9rem 1.5rem;
  border-bottom: 1px solid var(--rule);
}

header .brand {
  font: 600 1.1rem/1 var(--mono);
  color: var(--fg);
  text-decoration: none;
}

header .nav {
  font: 0.85rem/1 var(--mono);
  text-decoration: none;
}

header .nav.here { color: var(--accent); }

header .spacer { flex: 1; }

header .version {
  font: 0.8rem/1 var(--mono);
  color: var(--fg-soft);
}

header .version select {
  font: inherit;
  color: inherit;
  background: var(--bg-soft);
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: 0.1rem 0.2rem;
}

/* The picker replaces the static label once versions.json has loaded, so the
   two are never both on screen. */
header .version:has(select:not([hidden])) .version-label { display: none; }

/* Page shell --------------------------------------------------------- */

.wrap {
  display: flex;
  gap: 3rem;
  align-items: flex-start;
  padding: 2rem 1.5rem 6rem;
}

main {
  min-width: 0;
  max-width: var(--measure);
}

.prose { overflow-wrap: break-word; }

/* Sidebar ------------------------------------------------------------ */

/* The curated rail (see the menu in hugo.toml). It scrolls on its own once
   it outgrows the window, so a long manual never pushes the entry you are
   reaching for below the fold of a sticky column. */
.sidenav {
  position: sticky;
  top: 2rem;
  flex: 0 0 12rem;
  max-height: calc(100vh - 4rem);
  overflow-y: auto;
  font-size: 0.9rem;
  line-height: 1.5;
}

.sidenav h5 {
  margin: 1.5rem 0 0.4rem;
  font: 600 0.7rem/1 var(--sans);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--fg-soft);
}

.sidenav h5:first-child { margin-top: 0; }

.sidenav a {
  display: block;
  padding: 0.18rem 0;
  color: var(--fg);
  text-decoration: none;
}

.sidenav a:hover { color: var(--link); }

.sidenav a.active {
  color: var(--accent);
  font-weight: 600;
}

/* Entries naming a command, marked mono in hugo.toml. Not <code>: the menu
   name is a plain string, so the face is set here. */
.sidenav a.mono {
  font-family: var(--mono);
  font-size: 0.86em;
}

.toc {
  position: sticky;
  top: 2rem;
  flex: 0 0 14rem;
  font-size: 0.85rem;
  line-height: 1.5;
  color: var(--fg-soft);
}

.toc h5 {
  margin: 0 0 0.5rem;
  font: 600 0.7rem/1 var(--sans);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--fg-soft);
}

.toc ul {
  margin: 0;
  padding-left: 1rem;
  list-style: none;
}

.toc > ul { padding-left: 0; }

.toc a {
  display: block;
  padding: 0.15rem 0;
  color: var(--fg-soft);
  text-decoration: none;
}

.toc a:hover { color: var(--link); }

/* Home --------------------------------------------------------------- */

.hero {
  max-width: var(--measure);
  margin-bottom: 2.5rem;
}

.hero .wordmark {
  margin: 0;
  font: 700 2.6rem/1 var(--mono);
  letter-spacing: -0.02em;
}

.hero .tagline {
  margin: 0.6rem 0 1.4rem;
  font-size: 1.15rem;
  color: var(--fg-soft);
}

.hero-install { margin: 0; }

/* Prose -------------------------------------------------------------- */

h1, h2, h3, h4 {
  line-height: 1.25;
  margin: 2.2rem 0 0.8rem;
}

h1 { font-size: 1.9rem; }
h2 { font-size: 1.35rem; }
h3 { font-size: 1.1rem; }

/* The first heading of a published file is its own title; it should sit
   where a page title sits, not two lines below the header. */
.prose > h1:first-child { margin-top: 0; }

p, ul, ol, blockquote { margin: 0 0 1rem; }

blockquote {
  margin-left: 0;
  padding-left: 1rem;
  border-left: 3px solid var(--rule);
  color: var(--fg-soft);
}

img {
  max-width: 100%;
  height: auto;
  border-radius: 6px;
}

sub { color: var(--fg-soft); }

hr {
  border: 0;
  border-top: 1px solid var(--rule);
  margin: 2rem 0;
}

code {
  font-family: var(--mono);
  font-size: 0.87em;
  background: var(--bg-soft);
  border-radius: 4px;
  padding: 0.1em 0.3em;
}

pre {
  background: var(--bg-soft);
  border: 1px solid var(--rule);
  border-radius: 6px;
  padding: 0.9rem 1rem;
  overflow-x: auto;
}

pre code {
  background: none;
  padding: 0;
  font-size: 0.85rem;
  line-height: 1.5;
}

table {
  border-collapse: collapse;
  width: 100%;
  margin-bottom: 1rem;
}

th, td {
  border: 1px solid var(--rule);
  padding: 0.4rem 0.6rem;
  text-align: left;
}

/* Section indexes ---------------------------------------------------- */

/* A section's children, each with the one line its summary front matter
   gives it (see list.html). */
.pagelist { margin: 1.6rem 0 0; }

.pagelist dt { margin-top: 1.1rem; }

.pagelist dt a { text-decoration: none; }

.pagelist dd {
  margin: 0.15rem 0 0;
  color: var(--fg-soft);
}

/* Casts -------------------------------------------------------------- */

/* A recording of the TUI, with the keys it presses named underneath — the
   caption is where the keystrokes are, because VHS cannot draw them into the
   frame (see the cast shortcode). */
figure.cast { margin: 1.6rem 0; }

figure.cast video {
  display: block;
  width: 100%;
  height: auto;
  /* `auto` first, so the real ratio wins the moment metadata lands; the
     fallback is the tape size docs/tapes/house.tape sets, which is what a
     cast recorded by this repo's own harness comes back as. Without it a
     video lays out at the spec's 300x150 until metadata arrives and then
     jumps, shoving the prose under it down the page. */
  aspect-ratio: auto 1200 / 640;
  background: var(--bg-soft);
  border: 1px solid var(--rule);
  border-radius: 6px;
}

figure.cast figcaption {
  margin-top: 0.55rem;
  font-size: 0.85rem;
  color: var(--fg-soft);
}

/* The separators are in the markup (see the cast shortcode), so they need
   nothing here but a colour that keeps them behind the words — the soft
   foreground, not the rule colour, which is mixed for 1px lines and is all
   but invisible as text. */
.keys .sep { color: var(--fg-soft); }

/* Scoped to the caption, not a bare kbd: goldmark runs with unsafe = true,
   so a <kbd> written into the README would otherwise pick up keycap chrome
   with no cast anywhere near it. */
.keys kbd {
  font: 0.85em var(--mono);
  color: var(--fg);
  background: var(--bg-soft);
  border: 1px solid var(--rule);
  border-bottom-width: 2px;
  border-radius: 4px;
  padding: 0.1em 0.4em;
}

/* Narrow screens ----------------------------------------------------- */

/* Two rails and a reading column need 75rem: 40rem of measure, 12 of
   sidebar, 14 of rail, and the padding and gaps between them. Below that the
   "On this page" rail goes first — it is the one a scrollbar substitutes for,
   and the sidebar is the only way between pages. The cost is real and worth
   naming: on a 1000px window the README and SCOPE lose a rail they used to
   have. The alternative was both rails standing while the prose they frame
   ran at 26rem, which is worse for the same two pages. */
@media (max-width: 75rem) {
  .toc { display: none; }
}

@media (max-width: 60rem) {
  /* The sidebar stays — it is the only way between pages — but folds into a
     row of links above the text, because a column beside the prose at this
     width leaves neither of them room. The group headings go with the
     column: stacked they were signposts, in a row they are noise.
     This is a rule for a short menu. A row of twenty links is a screenful
     of undifferentiated names before a phone reader reaches a word of
     prose, and with the headings suppressed nothing separates the groups —
     when the manual gets there, this is the rule to revisit, and the answer
     is a fold, not a script. */
  .wrap {
    display: block;
    padding: 1.5rem 1.25rem 4rem;
  }

  .sidenav {
    position: static;
    max-height: none;
    overflow: visible;
    margin-bottom: 1.5rem;
    padding-bottom: 0.9rem;
    border-bottom: 1px solid var(--rule);
  }

  .sidenav h5 { display: none; }

  .sidenav a {
    display: inline-block;
    margin-right: 1.1rem;
  }
  .hero .wordmark { font-size: 2.1rem; }
  /* The README's pipeline table is three columns of prose. It is set tighter
     here to leave the widest column room, and deliberately left as a table:
     making it scroll sideways costs more than it buys — auto layout already
     gives the prose column most of the width, and a table overridden to
     display:block leaves the accessibility tree with no rows or columns at
     exactly the size where the table is hardest to follow. */
  th, td {
    padding: 0.3rem 0.4rem;
    font-size: 0.92rem;
  }
}