/* cohere docs — the survey chart.
   Two papers carry the thesis: authored content sits on buff (land),
   derived content on white (soundings). Chart magenta is reserved for
   drift and hazard — nothing decorative may use it. */

:root {
  --ground: #e7ecec;        /* bathymetric wash — the water the sheet sits on */
  --ground-line: #d5dede;   /* graticule */
  --paper: #f2ecdf;         /* buff — authored sheet */
  --paper-edge: #e4dbc8;
  --card: #fdfdfa;          /* white — derived blocks and sheets */
  --ink: #22303a;           /* deep chart ink */
  --ink-soft: #5b6a70;
  --contour: #8a6b4d;       /* contour brown — rules and structure */
  --contour-faint: #cbbca2;
  --water: #2e6e8e;         /* bathy blue — links */
  --hazard: #c21e6e;        /* chart magenta — drift/hazard ONLY */
  --serif: "Source Serif 4", Georgia, serif;
  --display: "Marcellus", Georgia, serif;
  --mono: "Fragment Mono", ui-monospace, "SF Mono", monospace;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { font-size: 17px; }

body {
  font-family: var(--serif);
  font-weight: 380;
  color: var(--ink);
  line-height: 1.62;
  background-color: var(--ground);
  background-image:
    linear-gradient(var(--ground-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--ground-line) 1px, transparent 1px);
  background-size: 56px 56px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 0 1.25rem 4rem;
}

.skip {
  position: absolute;
  left: -9999px;
  background: var(--card);
  padding: 0.5rem 1rem;
}
.skip:focus { left: 1rem; top: 1rem; z-index: 10; }

a { color: var(--water); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 2px solid var(--water); outline-offset: 2px; }

/* -- masthead: the chart's title block ----------------------------------- */

.masthead {
  width: min(46rem, 100%);
  text-align: center;
  padding: 2.4rem 0 1.1rem;
}

.brand {
  font-family: var(--display);
  font-size: 2rem;
  letter-spacing: 0.42em;
  text-indent: 0.42em; /* recenters tracked caps */
  text-transform: uppercase;
  color: var(--ink);
  text-decoration: none;
}

.brand-sub {
  font-family: var(--serif);
  font-style: italic;
  color: var(--ink-soft);
  font-size: 0.95rem;
  margin-top: 0.15rem;
}

.masthead nav {
  margin-top: 1.15rem;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.1rem 1.15rem;
}

.masthead nav a {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--ink-soft);
  text-decoration: none;
  padding: 0.2rem 0;
}

.masthead nav a:hover { color: var(--ink); }
.masthead nav a[aria-current="page"] {
  color: var(--ink);
  border-bottom: 2px solid var(--contour);
}

/* -- graduation strip: the neatline's tick scale -------------------------- */

.graduation {
  width: min(46rem, 100%);
  height: 9px;
  border-top: 1px solid var(--ink);
  border-bottom: 1px solid var(--ink);
  background-image:
    repeating-linear-gradient(90deg, var(--ink) 0 1px, transparent 1px 10px),
    repeating-linear-gradient(90deg, var(--ink) 0 1px, transparent 1px 50px);
  background-size: 100% 3px, 100% 7px;
  background-position: bottom, bottom;
  background-repeat: no-repeat;
  margin-bottom: 2.2rem;
}

/* -- the sheet: buff for authored pages, white for derived ---------------- */

.sheet {
  width: min(46rem, 100%);
  background: var(--paper);
  border: 1px solid var(--contour);
  box-shadow: 0 0 0 5px var(--paper), 0 0 0 6px var(--contour),
    0 18px 40px -24px rgba(34, 48, 58, 0.45);
  padding: 3rem 3.4rem 3.4rem;
}

.page-derived .sheet { background: var(--card); box-shadow: 0 0 0 5px var(--card), 0 0 0 6px var(--contour), 0 18px 40px -24px rgba(34, 48, 58, 0.45); }

/* -- type ------------------------------------------------------------------ */

.page-title {
  font-family: var(--display);
  font-weight: 400;
  font-size: 1.75rem;
  letter-spacing: 0.06em;
  border-bottom: 1px solid var(--contour);
  padding-bottom: 0.7rem;
  margin-bottom: 1.6rem;
}

/* land features: tracked roman caps */
h2 {
  font-family: var(--display);
  font-weight: 400;
  font-size: 1.02rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink);
  margin: 2.3rem 0 0.8rem;
}

/* water features: italic serif, the chart convention */
h3 {
  font-family: var(--serif);
  font-style: italic;
  font-weight: 480;
  font-size: 1.12rem;
  margin: 1.8rem 0 0.6rem;
}

h4 {
  font-family: var(--mono);
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin: 1.5rem 0 0.5rem;
}

p { margin: 0 0 1rem; }
p:last-child { margin-bottom: 0; }

ul, ol { margin: 0 0 1rem 1.4rem; }
li { margin-bottom: 0.35rem; }

strong { font-weight: 620; }

blockquote {
  font-style: italic;
  color: var(--ink-soft);
  border-left: 2px solid var(--contour);
  padding-left: 1.1rem;
  margin: 1.4rem 0;
}

hr {
  border: none;
  border-top: 1px dashed var(--contour-faint);
  margin: 2rem 0;
}

/* -- code: soundings -------------------------------------------------------- */

code {
  font-family: var(--mono);
  font-size: 0.83em;
  /* keep ~> and -> literal; an arrow ligature in Elixir version specs lies */
  font-variant-ligatures: none;
  font-feature-settings: "liga" 0, "calt" 0;
}

p code, li code, h2 code, h3 code, blockquote code {
  background: rgba(46, 110, 142, 0.08);
  padding: 0.08em 0.3em;
  border-radius: 2px;
}

pre {
  background: var(--card);
  border: 1px solid var(--paper-edge);
  border-left: 3px solid var(--contour-faint);
  padding: 1rem 1.15rem;
  overflow-x: auto;
  margin: 0 0 1.15rem;
  line-height: 1.5;
}

.page-derived pre {
  background: #f2f6f7; /* soundings sit on pale water in a white sheet */
  border-color: var(--ground-line);
}

pre code { font-size: 0.78rem; background: none; padding: 0; }

/* -- the signature: edition notices on derived content ---------------------- */

.stamp {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.05em;
  color: var(--ink-soft);
  border-top: 1px solid var(--contour);
  border-bottom: 1px solid var(--contour);
  padding: 0.4rem 0.1rem;
  margin: 1.6rem 0;
}

.stamp::before { content: "⌖ "; color: var(--contour); }

/* embedded document panels on the self page */
.derived-doc, .authored-doc {
  border: 1px solid var(--paper-edge);
  padding: 1.6rem 1.8rem;
  margin: 1.2rem 0 1.8rem;
}
.derived-doc { background: var(--card); }
.page-derived .authored-doc { background: var(--paper); border-color: var(--contour-faint); }

/* -- hazard: chart magenta, drift semantics only ----------------------------- */

.hazard { color: var(--hazard); }

pre .hazard { font-weight: 400; }

/* -- hero (index only) -------------------------------------------------------- */

.hero {
  position: relative;
  padding: 1.2rem 0 0.4rem;
  margin-bottom: 1rem;
}

.hero-contours {
  position: absolute;
  right: -2.2rem;
  top: -1.8rem;
  width: 300px;
  max-width: 55%;
  opacity: 0.5;
  pointer-events: none;
}

.hero-thesis {
  position: relative;
  font-family: var(--serif);
  font-style: italic;
  font-weight: 420;
  font-size: 1.42rem;
  line-height: 1.5;
  max-width: 33ch;
  margin-bottom: 1.2rem;
}

/* -- ladder rungs (index + ladder pages) --------------------------------------- */

.rungs { list-style: none; margin: 1.2rem 0 1.4rem; }

.rungs li {
  display: grid;
  grid-template-columns: 3.2rem 11.5rem 1fr;
  gap: 0 1rem;
  padding: 0.55rem 0.2rem;
  border-top: 1px solid var(--contour-faint);
  align-items: baseline;
}

.rungs li:last-child { border-bottom: 1px solid var(--contour-faint); }

.rungs .lvl {
  font-family: var(--mono);
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  color: var(--contour);
}

.rungs .what {
  font-family: var(--display);
  font-size: 0.85rem;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.rungs .how { color: var(--ink-soft); font-size: 0.92rem; }

/* -- footer --------------------------------------------------------------------- */

footer {
  width: min(46rem, 100%);
  text-align: center;
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.05em;
  color: var(--ink-soft);
  margin-top: 2.4rem;
}

footer p { margin: 0.2rem 0; }
footer a { color: var(--ink-soft); }

/* -- small screens ----------------------------------------------------------------- */

@media (max-width: 640px) {
  html { font-size: 16px; }
  .sheet { padding: 1.8rem 1.3rem 2rem; }
  .rungs li { grid-template-columns: 2.4rem 1fr; }
  .rungs .how { grid-column: 2; margin-top: 0.15rem; }
  .hero-contours { display: none; }
  .hero-thesis { max-width: none; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
}