/* One stylesheet, no framework, no web fonts.
 *
 * A font file is 100-300KB fetched from someone else's server on every first
 * visit, for a typeface most readers will not notice. The system stack is
 * already on the device, renders instantly, and is what the reader's OS
 * chose for reading. */

:root {
  --ink: #16181d;
  --soft: #5c6472;
  --line: #e3e6ec;
  --bg: #ffffff;
  --panel: #f7f8fa;
  --accent: #2f5bd7;
  --measure: 34rem;   /* ~66 characters: the line length prose is read at */
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #e8eaf0;
    --soft: #9aa3b2;
    --line: #272b33;
    --bg: #101216;
    --panel: #171a20;
    --accent: #7ea2ff;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  padding: 0 1.25rem 4rem;
  background: var(--bg);
  color: var(--ink);
  font: 1.05rem/1.65 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  -webkit-text-size-adjust: 100%;
}

main, .top, footer { max-width: var(--measure); margin: 0 auto; }

/* --- header --------------------------------------------------------- */

.top {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1rem;
  align-items: baseline;
  padding: 1.5rem 0 1rem;
  border-bottom: 1px solid var(--line);
}

.brand {
  font-weight: 700;
  font-size: 1.15rem;
  letter-spacing: -0.01em;
  text-decoration: none;
  color: var(--ink);
}

.top nav { display: flex; flex-wrap: wrap; gap: 0.9rem; }
.top nav a { color: var(--soft); text-decoration: none; font-size: 0.92rem; }
.top nav a:hover { color: var(--accent); }

/* --- lists ---------------------------------------------------------- */

.lede { padding: 2.5rem 0 1rem; }
.lede h1 { font-size: 1.9rem; line-height: 1.2; margin: 0 0 0.4rem; letter-spacing: -0.02em; }
.lede p { color: var(--soft); margin: 0; }

.pieces { list-style: none; padding: 0; margin: 0; }
.pieces li { padding: 1.5rem 0; border-top: 1px solid var(--line); }
.pieces h2 { font-size: 1.25rem; line-height: 1.3; margin: 0.25rem 0 0.4rem; }
.pieces h2 a { color: var(--ink); text-decoration: none; }
.pieces h2 a:hover { color: var(--accent); }
.pieces p { margin: 0 0 0.5rem; color: var(--soft); }

.ch { font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--soft); }
.ch a { color: inherit; text-decoration: none; }
.ch a:hover { color: var(--accent); }

time { font-size: 0.85rem; color: var(--soft); font-variant-numeric: tabular-nums; }
.empty { color: var(--soft); padding: 2rem 0; }

/* --- the article ---------------------------------------------------- */

article { padding: 2.5rem 0 0; }
article h1 { font-size: 2rem; line-height: 1.15; margin: 0.4rem 0 0.6rem; letter-spacing: -0.02em; }
.summary { font-size: 1.15rem; color: var(--soft); margin: 0 0 0.6rem; }

.body { margin-top: 2rem; }
.body h2 { font-size: 1.35rem; margin: 2.2rem 0 0.6rem; line-height: 1.3; }
.body h3 { font-size: 1.1rem; margin: 1.8rem 0 0.5rem; }
.body p { margin: 0 0 1.15rem; }
.body a { color: var(--accent); }
.body ul, .body ol { padding-left: 1.3rem; }
.body li { margin-bottom: 0.5rem; }

.body blockquote {
  margin: 1.5rem 0;
  padding: 0.2rem 0 0.2rem 1rem;
  border-left: 3px solid var(--line);
  color: var(--soft);
}

.body code {
  font: 0.9em/1.5 ui-monospace, SFMono-Regular, Menlo, monospace;
  background: var(--panel);
  padding: 0.1em 0.35em;
  border-radius: 4px;
}

.body pre {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 1rem;
  /* Code and tables are the two things allowed to be wider than the measure,
     and they scroll inside themselves rather than making the page scroll. */
  overflow-x: auto;
}
.body pre code { background: none; padding: 0; }

.body table { border-collapse: collapse; width: 100%; font-size: 0.95rem; display: block; overflow-x: auto; }
.body th, .body td { border: 1px solid var(--line); padding: 0.5rem 0.7rem; text-align: left; }
.body th { background: var(--panel); }

.body img { max-width: 100%; height: auto; }

/* --- sources and footer --------------------------------------------- */

.sources {
  margin-top: 3rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
  font-size: 0.95rem;
}
.sources h2 { font-size: 1rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--soft); margin: 0 0 0.6rem; }
.sources a { color: var(--accent); }

footer {
  margin-top: 4rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--line);
  color: var(--soft);
  font-size: 0.88rem;
}
footer p { margin: 0 0 0.5rem; }
footer a { color: var(--accent); }

/* --- diagrams -------------------------------------------------------- */
/* Mermaid, unrendered on purpose - see `_diagram_fence`. Framed and
 * labelled so it reads as a diagram in source form rather than as a page
 * that failed to load something. */

.body .diagram {
  margin: 1.8rem 0;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  overflow: hidden;
}

.body .diagram figcaption {
  padding: 0.45rem 0.8rem;
  border-bottom: 1px solid var(--line);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--soft);
}

.body .diagram pre {
  margin: 0;
  border: 0;
  border-radius: 0;
  background: none;
  font: 0.85rem/1.5 ui-monospace, SFMono-Regular, Menlo, monospace;
  padding: 0.9rem;
  overflow-x: auto;
}