/* Hand-written CSS. Fonts are bundled in fonts/ (Instrument Serif for headlines, Instrument Sans for text). */
@font-face { font-family:"Instrument Serif"; src:url("fonts/instrument-serif-latin-400-normal.woff2") format("woff2"); font-weight:400; font-style:normal; font-display:swap; }
@font-face { font-family:"Instrument Serif"; src:url("fonts/instrument-serif-latin-400-italic.woff2") format("woff2"); font-weight:400; font-style:italic; font-display:swap; }
@font-face { font-family:"Instrument Sans"; src:url("fonts/instrument-sans-latin-wght-normal.woff2") format("woff2"); font-weight:400 700; font-style:normal; font-display:swap; }

:root {
  --bg:#fcfcfb; --ink:#15171c; --muted:#5b606a; --line:#e7e8ea; --faint:#f2f3f5; --bar:#c6cad2;
  --blue:#2158d6; --blue-soft:#e9effc; --amber:#d9791c;
  --serif:"Instrument Serif", Georgia, "Times New Roman", serif; --sans:"Instrument Sans", system-ui, -apple-system, "Segoe UI", sans-serif;
}
* { box-sizing:border-box; }
[hidden] { display:none !important; }
.sr-only { position:absolute; width:1px; height:1px; margin:-1px; padding:0; overflow:hidden; clip:rect(0 0 0 0); white-space:nowrap; border:0; }
:focus-visible { outline:3px solid var(--blue); outline-offset:3px; border-radius:3px; }
html { scroll-behavior:smooth; -webkit-text-size-adjust:100%; }
body { margin:0; background:var(--bg); color:var(--ink); font:17px/1.65 var(--sans); }
a { color:var(--blue); text-underline-offset:.18em; }
code { font:.88em ui-monospace, "SF Mono", Menlo, Consolas, monospace; background:var(--faint); padding:.1em .35em; border-radius:4px; overflow-wrap:anywhere; }
.skip { position:absolute; left:-999px; top:.5rem; background:var(--ink); color:#fff; padding:.5rem .9rem; border-radius:6px; z-index:20; }
.skip:focus { left:.5rem; }
.sep::before { content:"\00b7"; margin:0 .6em; color:var(--muted); }
h1, h2, h3 { font-family:var(--serif); font-weight:400; margin:0; letter-spacing:-.01em; }
h2 { font-size:clamp(1.9rem, 4.2vw, 2.7rem); line-height:1.12; }
h3 { font-size:clamp(1.5rem, 3vw, 1.9rem); line-height:1.2; }
p { margin:0 0 1rem; }

header.top { display:flex; justify-content:space-between; align-items:center; max-width:70rem; margin:0 auto; padding:1.3rem 1.5rem; }
.brand { color:var(--ink); text-decoration:none; font-weight:600; font-size:.95rem; letter-spacing:.01em; }
.help-link, .linklike { font:inherit; font-size:.92rem; background:none; border:0; padding:.35rem .1rem; color:var(--muted); text-decoration:underline; text-underline-offset:.2em; text-decoration-color:var(--bar); cursor:pointer; }
.help-link:hover, .linklike:hover { color:var(--blue); text-decoration-color:currentColor; }

/* ---------- hero ---------- */
main { max-width:70rem; margin:0 auto; padding:0 1.5rem; }
.hero { padding:clamp(3rem, 12vh, 7rem) 0 clamp(3rem, 10vh, 6rem); max-width:58rem; }
.kicker { font-size:.85rem; letter-spacing:.1em; text-transform:uppercase; color:var(--blue); font-weight:600; margin-bottom:1.2rem; }
.hero h1 { font-size:clamp(2.6rem, 7.2vw, 5rem); line-height:1.03; letter-spacing:-.02em; }
.deck { margin:1.6rem 0 2rem; font-size:1.2rem; line-height:1.55; color:#3c414a; max-width:38rem; }
.facts { display:flex; flex-wrap:wrap; gap:1rem 2.5rem; margin:0 0 2.2rem; padding:1.2rem 0 0; border-top:1px solid var(--line); }
.facts div { display:flex; flex-direction:column-reverse; }
.facts dt { font-size:.82rem; color:var(--muted); }
.facts dd { margin:0; font:400 2rem/1.1 var(--serif); }
.start { display:inline-block; font-weight:600; font-size:.95rem; text-decoration:none; border-bottom:2px solid var(--blue); padding-bottom:.15rem; }
.start::after { content:"  \2193"; }

/* ---------- chapters ---------- */
.chapter { padding:clamp(3rem, 9vh, 5.5rem) 0; border-top:1px solid var(--line); }
.num { display:inline-block; align-self:flex-start; font:600 .8rem/1 var(--sans); letter-spacing:.1em; color:var(--blue); background:var(--blue-soft); padding:.35rem .6rem; border-radius:999px; margin-bottom:1rem; }
.text { max-width:38rem; margin-bottom:2.2rem; }
.text p { font-size:1.1rem; color:#3c414a; margin-top:1rem; }
.cap { font-size:.82rem; letter-spacing:.06em; text-transform:uppercase; color:var(--muted); font-weight:600; margin:0 0 1.1rem; }
figure { margin:0; }
.chart { max-width:52rem; }

/* scrollytelling: sticky chart beside the text, only on wide screens */
.scrolly { display:grid; grid-template-columns:minmax(0,24rem) minmax(0,1fr); gap:4rem; align-items:start; }
.steps .step { min-height:70vh; display:flex; flex-direction:column; justify-content:center; padding:1rem 0; opacity:.72; transition:opacity .35s; border-left:3px solid transparent; padding-left:1.1rem; }
.steps .step.on { opacity:1; border-left-color:var(--blue); }
.steps .step p:not(.num) { font-size:1.1rem; color:#262a31; margin-top:1rem; }
.stage { position:sticky; top:12vh; max-width:34rem; }

/* month columns */
.cols { list-style:none; margin:0 0 1rem; padding:0; display:grid; grid-template-columns:repeat(12, 1fr); gap:.35rem; align-items:end; height:15rem; }
.col { display:flex; flex-direction:column; justify-content:flex-end; align-items:center; height:100%; font-size:.75rem; color:var(--muted); min-width:0; }
.cbar { width:100%; height:calc(var(--v) / var(--max) * 78%); background:var(--bar); border-radius:3px 3px 0 0; transition:background .35s; }
.cv { margin-bottom:.25rem; font-variant-numeric:tabular-nums; font-size:.7rem; }
.cm { margin-top:.4rem; }
.col.hi .cbar { background:var(--blue); } .col.hi .cv, .col.hi .cm { color:var(--blue); font-weight:600; }
.col.lo .cv, .col.lo .cm { color:var(--ink); font-weight:600; }
.panels { margin-top:1.8rem; display:grid; gap:1.6rem; }

/* horizontal bars: label, bar, value */
.bars { list-style:none; margin:0; padding:0; }
.bars .row { display:grid; grid-template-columns:minmax(0,1fr) auto; grid-template-areas:"lbl val" "track track"; gap:.15rem .8rem; padding:.55rem 0; align-items:baseline; }
.bars .lbl { grid-area:lbl; font-size:.98rem; }
.bars .val { grid-area:val; font-variant-numeric:tabular-nums; font-weight:600; font-size:.98rem; }
.bars .val small { font-weight:400; color:var(--muted); margin-left:.5rem; font-size:.82rem; }
.bars .track { grid-area:track; display:block; height:.6rem; background:var(--faint); border-radius:3px; overflow:hidden; }
.bars .fill { display:block; height:100%; width:calc(var(--v) / var(--max) * 100%); background:var(--bar); border-radius:3px; transition:width .9s cubic-bezier(.2,.7,.2,1); }
.bars .hi .fill { background:var(--blue); }
.bars.slim .row { padding:.35rem 0; } .bars.slim .lbl, .bars.slim .val { font-size:.9rem; }
.js .bars:not(.in) .fill { width:0; }
.note-row { font:italic 1.3rem/1.35 var(--serif); color:var(--blue); padding:0 0 .6rem; margin-top:-.2rem; }
.note-row::before { content:"\21b3  "; font-style:normal; }

/* segmented control (works without JavaScript) */
.toggle > input { position:absolute; opacity:0; pointer-events:none; }
.seg-control { display:inline-flex; padding:.2rem; background:var(--faint); border-radius:999px; margin-bottom:1.6rem; }
.seg-control label { padding:.4rem 1.1rem; border-radius:999px; font-size:.9rem; font-weight:600; color:var(--muted); cursor:pointer; min-height:2.25rem; display:inline-flex; align-items:center; }
#v-vol:checked ~ .seg-control label[for="v-vol"], #v-out:checked ~ .seg-control label[for="v-out"] { background:#fff; color:var(--ink); box-shadow:0 1px 3px rgba(20,25,40,.14); }
#v-vol:focus-visible ~ .seg-control label[for="v-vol"], #v-out:focus-visible ~ .seg-control label[for="v-out"] { outline:3px solid var(--blue); outline-offset:2px; }
#v-vol:checked ~ .view-out, #v-out:checked ~ .view-vol { display:none; }
.legend { list-style:none; display:flex; flex-wrap:wrap; gap:.3rem 1.1rem; margin:0 0 1.2rem; padding:0; font-size:.85rem; color:var(--muted); }
.sw { display:inline-block; width:.7rem; height:.7rem; border-radius:2px; margin-right:.4rem; }
.s-done { background:var(--blue); } .s-closed { background:#6b7380; } .s-prog { background:#93b0ee; } .s-new { background:var(--amber); } .s-cancel { background:#c6cad2; } .s-unk { background:#e6e8ec; }
.stacks { list-style:none; margin:0; padding:0; }
.stacks li { padding:.55rem 0; }
.stacks .lbl { display:block; font-size:.98rem; margin-bottom:.3rem; }
.stack { display:flex; height:1.7rem; border-radius:4px; overflow:hidden; gap:1px; background:#fff; }
.seg { width:calc(var(--w) * 1%); min-width:2px; display:flex; align-items:center; justify-content:center; font-size:.72rem; font-weight:600; }
.seg.s-done, .seg.s-closed, .seg.s-new { color:#fff; } .seg.s-prog, .seg.s-cancel, .seg.s-unk { color:var(--ink); }
.callout { margin:1.6rem 0 0; padding:1rem 1.2rem; border-left:3px solid var(--amber); background:#fdf5ec; border-radius:0 8px 8px 0; font-size:.98rem; }

/* heatmap */
.heat { display:grid; gap:2px; max-width:48rem; }
.hrow { display:grid; grid-template-columns:2.4rem repeat(24, 1fr); gap:2px; align-items:center; }
.hd { font-size:.75rem; color:var(--muted); }
.hl { font-size:.7rem; color:var(--muted); text-align:left; overflow:visible; white-space:nowrap; }
.cell { display:block; aspect-ratio:1 / 1; border-radius:3px; background:rgb(33 88 214 / var(--a)); cursor:crosshair; }
.cell:hover { outline:2px solid var(--ink); outline-offset:1px; }
.cell:focus-visible { outline:3px solid var(--ink); outline-offset:1px; z-index:1; position:relative; }
.cell.peak { box-shadow:0 0 0 2px var(--bg), 0 0 0 4px var(--amber); position:relative; }
.readout { min-height:3.4em; margin:1.1rem 0 .4rem; font:italic 1.4rem/1.3 var(--serif); }
.scale { display:flex; align-items:center; gap:.6rem; font-size:.78rem; color:var(--muted); margin:0 0 .6rem; }
.scale i { width:7rem; height:.5rem; border-radius:3px; background:linear-gradient(90deg, rgb(33 88 214 / .05), rgb(33 88 214 / 1)); }

/* numbers behind a chart, quiet disclosure */
.nums { margin-top:1.8rem; border-top:1px solid var(--line); padding-top:.6rem; }
.nums summary, .all-sql > summary { cursor:pointer; font-size:.9rem; color:var(--muted); padding:.4rem 0; min-height:2.25rem; }
.nums summary:hover, .all-sql > summary:hover { color:var(--blue); }
.nums-body { display:grid; grid-template-columns:repeat(auto-fit, minmax(16rem, 1fr)); gap:1.5rem 2.5rem; padding:.6rem 0 .5rem; align-items:start; }
.nums-body:has(table:only-child) { grid-template-columns:minmax(0,28rem); }
table { border-collapse:collapse; width:100%; font-size:.88rem; font-variant-numeric:tabular-nums; }
th, td { padding:.35rem .6rem .35rem 0; border-bottom:1px solid var(--line); text-align:left; vertical-align:top; }
th.n, td.n { text-align:right; padding-right:0; padding-left:.8rem; } thead th { color:var(--muted); font-weight:600; font-size:.78rem; letter-spacing:.04em; }
tbody th { font-weight:400; }
.nums-body > table:has(th:nth-child(7)) { grid-column:1 / -1; display:block; overflow-x:auto; }

/* caveats and method */
.method { max-width:46rem; margin:0; }
.method h2 { font-size:clamp(1.6rem, 3.4vw, 2.1rem); margin:0 0 1rem; } .method h2 + ul + h2, .method ol + details { margin-top:2.5rem; }
.caveats, .how { padding-left:1.2rem; margin:0 0 2.5rem; } .caveats li, .how li { margin:.55rem 0; }
.how { margin-bottom:1.5rem; }
.all-sql { border-top:1px solid var(--line); border-bottom:1px solid var(--line); padding:.4rem 0; margin-bottom:2rem; }
.sql { border-top:1px solid var(--line); }
.sql summary { cursor:pointer; padding:.5rem 0; font-size:.92rem; display:flex; flex-direction:column; gap:.1rem; }
.sql summary span { color:var(--muted); font-size:.85rem; }
pre { margin:.2rem 0 1rem; padding:1rem 1.1rem; background:var(--faint); border-radius:8px; overflow-x:auto; font:.82rem/1.6 ui-monospace, "SF Mono", Menlo, Consolas, monospace; }
.source { font-size:.9rem; color:var(--muted); }

footer { max-width:70rem; margin:0 auto; padding:2rem 1.5rem 3rem; border-top:1px solid var(--line); font-size:.88rem; color:var(--muted); }
footer p { margin:.3rem 0; } footer a { color:var(--muted); } footer .linklike { padding:0; font-size:inherit; }

/* help: a centred sheet */
dialog.help { border:0; padding:0; border-radius:16px; width:min(34rem, calc(100vw - 2rem)); max-height:calc(100dvh - 3rem); background:var(--bg); color:var(--ink); box-shadow:0 30px 80px -20px rgba(20,25,40,.45); }
dialog.help::backdrop { background:rgba(21,23,28,.38); }
.help-inner { padding:1.5rem 1.8rem 2rem; font-size:1rem; }
.help-bar { display:flex; align-items:baseline; justify-content:space-between; gap:1rem; margin-bottom:1rem; }
.help-inner h2 { font-size:1.8rem; }
.help-close { font:600 .9rem var(--sans); background:none; border:1px solid var(--line); border-radius:999px; padding:.35rem .9rem; min-height:2.25rem; cursor:pointer; color:var(--ink); }
.help-close:hover { border-color:var(--blue); color:var(--blue); }
.help-steps { padding-left:1.3rem; margin:0 0 1.2rem; } .help-steps li { margin:.7rem 0; padding-left:.2rem; } .help-steps li::marker { font-weight:700; color:var(--blue); }
.gloss { border-top:1px solid var(--line); border-bottom:1px solid var(--line); padding:.7rem 0; }
.gloss summary { cursor:pointer; font-weight:600; font-size:.95rem; }
.gloss dt { font-weight:600; margin-top:.8rem; } .gloss dd { margin:.1rem 0 0; color:var(--muted); font-size:.95rem; }
.why-title { margin-top:2rem; padding-top:1.5rem; border-top:1px solid var(--line); margin-bottom:.8rem; }
body:has(dialog.help[open]) { overflow:hidden; }

/* wide screens: the sticky stage swaps panels as you read. Elsewhere everything is just visible. */
@media (min-width:1000px) {
  .js .panel { display:none; }
  .js .stage[data-focus="days"] .panel[data-for="days"], .js .stage[data-focus="types"] .panel[data-for="types"] { display:block; animation:rise .4s ease-out; }
}
@keyframes rise { from { opacity:0; transform:translateY(.6rem); } }
@media (max-width:999px) {
  .scrolly { display:block; }
  .steps .step { min-height:0; opacity:1; padding:0 0 1.8rem; border-left:0; } .steps .step:first-child { padding-top:0; }
  .stage { position:static; max-width:none; margin-top:1rem; }
}
@media (max-width:600px) {
  body { font-size:16px; } main, header.top, footer { padding-left:1.1rem; padding-right:1.1rem; }
  .cols { height:12rem; gap:.2rem; } .cv { font-size:.62rem; } .col { font-size:.68rem; }
  .hrow { grid-template-columns:2rem repeat(24, 1fr); gap:1px; } .heat { gap:1px; } .cell { border-radius:2px; }
  .help-inner { padding:1.2rem 1.2rem 1.6rem; }
}
@media (prefers-reduced-motion:reduce) { html { scroll-behavior:auto; } * { transition:none !important; animation:none !important; } }
@media print { header.top, .help-link, dialog, .skip, .start { display:none !important; } .steps .step { min-height:0; opacity:1; } .stage { position:static; } .panel { display:block !important; } }