/*
 * Balk engineering notes. Plain pages, no scripts: docs/mvp/eng-blog.md.
 * Colours, type and scale follow docs/design-system.md (the drawing set); the fonts are the
 * game's own (SIL Open Font License, fonts/LICENSE-*.txt).
 */

@font-face { font-family: "Playfair Display"; font-weight: 700; font-display: swap; src: url("/blog/fonts/playfair-display-latin-700-normal.woff2") format("woff2"); }
@font-face { font-family: "Inter"; font-weight: 400; font-display: swap; src: url("/blog/fonts/inter-latin-400-normal.woff2") format("woff2"); }
@font-face { font-family: "Inter"; font-weight: 700; font-display: swap; src: url("/blog/fonts/inter-latin-700-normal.woff2") format("woff2"); }

:root {
  color-scheme: light;
  /* The drawing set. */
  --paper: #fbf8f1;
  --ink: #2b2925;        /* graphite */
  --ink-soft: #57514a;   /* quiet */
  --ink-faint: #746c5f;  /* faint: captions, notes */
  --rule: #e3ddd1;
  --link: #8a5a3c;       /* link ink; note numbers too */
  --you: #4a6a8a;        /* "ours" in charts */
  --you-wash: #dfe8f0;
  --him: #a65f3f;        /* "theirs" in charts */
  --display: "Playfair Display", Georgia, serif;
  --serif: Georgia, "Times New Roman", serif;
  --sans: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  /* The scale. */
  --xs: 0.75rem; --sm: 0.875rem; --base: 1rem; --lg: 1.125rem; --xl: 1.25rem; --3xl: 1.875rem;
  --measure: 44.5rem;   /* ~65 characters of the prose face at lg */
  --note-w: 15rem;
  --note-gap: 2rem;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --paper: #1c1a17; --ink: #ece6da; --ink-soft: #c2b9ab; --ink-faint: #9a9183; --rule: #3b3731;
    --link: #d9a47f; --you: #8fb0d0; --you-wash: #33414f; --him: #c08a70;
  }
}
:root[data-theme="dark"] {
  color-scheme: dark;
  --paper: #1c1a17; --ink: #ece6da; --ink-soft: #c2b9ab; --ink-faint: #9a9183; --rule: #3b3731;
  --link: #d9a47f; --you: #8fb0d0; --you-wash: #33414f; --him: #c08a70;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 400 var(--lg)/1.6 var(--serif);
  -webkit-text-size-adjust: 100%;
}

.page { max-width: var(--measure); margin: 0 auto; padding: 2.5rem 16px 4rem; }

a { color: var(--link); text-underline-offset: 0.15em; }
strong, b { font-weight: 700; }

.masthead { font: 700 var(--xs)/1 var(--sans); letter-spacing: 0.14em; text-transform: uppercase; color: var(--ink-soft); margin-bottom: 2.5rem; }
.masthead a { color: inherit; text-decoration: none; }

h1 { font: 700 var(--3xl)/1.2 var(--display); margin: 0 0 0.5rem; }
h2 { font: 700 var(--xl)/1.3 var(--display); margin: 3rem 0 0.5rem; }
h3 { font: 700 var(--base)/1.3 var(--sans); margin: 1.75rem 0 0.5rem; }
p, ul, ol { margin: 0 0 1rem; }
li { margin-bottom: 0.35rem; }

.meta { font: 400 var(--sm)/1.4 var(--sans); color: var(--ink-faint); margin-bottom: 2rem; }
.lede { font-size: var(--xl); color: var(--ink-soft); }

code { font: 0.875em var(--mono); background: var(--rule); padding: 0.1em 0.3em; border-radius: 3px; }

/* Tables: numbers right-aligned, hairlines only. */
.table-wrap { overflow-x: auto; margin: 0 0 1.5rem; }
table { border-collapse: collapse; width: 100%; font: 400 var(--sm)/1.4 var(--sans); font-variant-numeric: tabular-nums; }
th, td { padding: 0.45rem 0.6rem 0.45rem 0; text-align: left; border-bottom: 1px solid var(--rule); vertical-align: top; }
th { font-weight: 700; color: var(--ink-soft); font-size: var(--xs); text-transform: uppercase; letter-spacing: 0.06em; }
td.n, th.n { text-align: right; white-space: nowrap; padding-left: 0.75rem; }
td .sub { display: none; color: var(--ink-soft); }
@media (max-width: 560px) {
  th.covers, td.covers { display: none; }
  td .sub { display: block; }
}

figure { margin: 1.5rem 0 2rem; }
figcaption { font: 400 var(--sm)/1.45 var(--sans); color: var(--ink-faint); margin-top: 0.5rem; }

.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(8.5rem, 1fr)); gap: 1rem; margin: 1.5rem 0 2rem; font-family: var(--sans); }
.stat b { display: block; font-size: var(--xl); line-height: 1.2; font-variant-numeric: tabular-nums; }
.stat span { display: block; font-size: var(--sm); line-height: 1.4; color: var(--ink-soft); }

.posts { list-style: none; padding: 0; }
.posts li { margin: 0 0 1.75rem; }
.posts a { font: 700 var(--xl)/1.3 var(--display); text-decoration: none; color: var(--ink); }
.posts a:hover { text-decoration: underline; }
.posts p { margin: 0.25rem 0 0; color: var(--ink-soft); }

.foot { margin-top: 3.5rem; padding-top: 1rem; border-top: 1px solid var(--rule); font: 400 var(--sm)/1.5 var(--sans); color: var(--ink-faint); }

/* A section set apart by space and its heading, never a box. */
.callout { margin: 3rem 0 0; }
.kicker { font: 700 var(--xs)/1 var(--sans); letter-spacing: 0.14em; text-transform: uppercase; color: var(--ink-soft); margin: 2rem 0 0.75rem; }

/*
 * Side notes: sources sit in the margin, level with the line that cites them.
 *   word<label class="sn-ref" for="sn-x"></label><input type="checkbox" id="sn-x" class="sn-toggle"><span class="sidenote">Source.</span>
 * Wide windows: notes float into the margin and stack. Narrow: the number is a button that
 * opens the note under the line. No scripts.
 */
article { counter-reset: sidenote; }
.sn-ref { counter-increment: sidenote; display: inline-block; padding: 0.45rem 0.3rem; margin: -0.45rem -0.15rem; cursor: pointer; }
.sn-ref::after { content: counter(sidenote); font: 700 var(--xs)/0 var(--sans); vertical-align: super; color: var(--link); }
.sidenote::before { content: counter(sidenote) ". "; font-weight: 700; color: var(--link); }
.sidenote { font: 400 var(--sm)/1.45 var(--sans); color: var(--ink-faint); }
.sidenote a { color: inherit; }
.sidenote cite { font-style: italic; }
.sn-toggle { position: absolute; opacity: 0; width: 1px; height: 1px; pointer-events: none; }

@media (max-width: 1179px) {
  .sn-toggle:focus-visible + .sidenote { outline: 2px solid var(--link); outline-offset: 1px; }
  .sidenote { display: none; }
  .sn-toggle:checked + .sidenote { display: block; margin: 0.5rem 0 0.75rem; padding: 0.5rem 0.75rem; border-left: 2px solid var(--rule); }
}

/*
 * Wide windows: one grid, centred. Everything (prose, tables, charts) is the main column;
 * the notes alone take the margin column beside it.
 */
@media (min-width: 1180px) {
  .page { max-width: calc(var(--measure) + var(--note-gap) + var(--note-w) + 32px); margin: 0 auto; }
  .masthead, article > *, .callout > *, .foot { max-width: var(--measure); }
  .sidenote { float: right; clear: right; width: var(--note-w); margin: 0.2rem calc(-1 * (var(--note-w) + var(--note-gap))) 1rem 0; }
}

/* Bar charts as page elements: labels wrap, colours follow the theme. */
.bars { font: 400 var(--sm)/1.3 var(--sans); color: var(--ink); margin: 0.5rem 0; }
.bars-head { font-weight: 700; margin: 0.9rem 0 0.25rem; }
.bar-row { display: grid; grid-template-columns: 15rem 1fr; gap: 0.75rem; align-items: center; margin: 0.4rem 0; }
.bar-label { color: var(--ink); }
.bar-track { display: flex; flex-wrap: wrap; align-items: center; row-gap: 0.15rem; min-width: 0; }
.bar-fill { display: block; height: 1.1rem; border-radius: 3px; background: var(--you); flex: none; max-width: 100%; }
.bar-fill.s2 { background: var(--him); }
.bar-fill.muted { background: var(--ink-faint); }
.bar-fill.faint { background: var(--you-wash); border-radius: 0 3px 3px 0; }
.bar-fill.solid-left { border-radius: 3px 0 0 3px; }
.bar-val { margin-left: 0.4rem; font-weight: 700; white-space: nowrap; color: var(--ink); }
@media (max-width: 560px) {
  .bar-row { grid-template-columns: 1fr; gap: 0.2rem; margin: 0.6rem 0; }
}