/* One stylesheet, one theme, no framework. Light only, by decision: the
   pictures in draw.js use the same variables through class names.

   The page is a worksheet: one situation stated as a sentence at the top,
   three numbered steps under it, hairlines instead of boxes. Three colours
   carry meaning and nothing else does -- measured (blue), prior (amber) and
   over target (red); everything else is ink on paper. */

@font-face { font-family: "Newsreader"; font-style: normal; font-weight: 200 800; font-display: swap;
             src: url("fonts/Newsreader-latin.woff2") format("woff2"); }
@font-face { font-family: "IBM Plex Sans"; font-style: normal; font-weight: 100 700; font-display: swap;
             src: url("fonts/IBMPlexSans-latin.woff2") format("woff2"); }
@font-face { font-family: "IBM Plex Mono"; font-style: normal; font-weight: 400; font-display: swap;
             src: url("fonts/IBMPlexMono-400-latin.woff2") format("woff2"); }
@font-face { font-family: "IBM Plex Mono"; font-style: normal; font-weight: 500; font-display: swap;
             src: url("fonts/IBMPlexMono-500-latin.woff2") format("woff2"); }

:root {
  color-scheme: light;
  --bg: #fbfaf7; --surface: #ffffff; --ink: #1a1917; --text-2: #6f6d66; --muted: #9a968c;
  --grid: #e5e2da; --border: #d3cfc5; --hair: #e5e2da;
  --blue: #2f6c9e; --orange: #a1662a; --red: #a12622;
  --measured-bg: #e3edf6; --prior-bg: #f5e9d9; --over-bg: #f7e1df;
  --ok-bg: #e6f0e8; --ok-ink: #1e6b34; --bad-bg: #f7e1df; --bad-ink: #a12622; --na-bg: #efece5;
  --sans: "IBM Plex Sans", -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  --serif: "Newsreader", Georgia, "Times New Roman", serif;
  --mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
}
* { box-sizing: border-box; }
html { font: 15px/1.55 var(--sans); }
body { margin: 0; background: var(--bg); color: var(--ink); }
p { margin: 0; }
a { color: var(--ink); text-decoration: underline; text-decoration-color: var(--muted); text-underline-offset: 3px; }
a:hover { text-decoration-color: var(--ink); }
code { font-family: var(--mono); font-size: 0.88em; background: var(--na-bg); padding: 0 4px; border-radius: 3px; }
button { font: inherit; color: inherit; }
.serif { font-family: var(--serif); }
.mono { font-family: var(--mono); font-variant-numeric: tabular-nums; }
.quiet, .hint, .muted { color: var(--text-2); }
.quiet.small, .hint { font-size: 0.87rem; }
.lab { font-size: 11.5px; letter-spacing: 0.07em; text-transform: uppercase; color: var(--text-2); }

/* badges: the three colours that mean something */
.badge { display: inline-block; white-space: nowrap; padding: 0 7px; border-radius: 3px; font-size: 11px; font-weight: 600; line-height: 18px; vertical-align: middle; letter-spacing: 0.02em; }
.badge.measured, .prov.measured { background: var(--measured-bg); color: var(--blue); }
.badge.prior, .prov.prior { background: var(--prior-bg); color: var(--orange); }
.badge.over { background: var(--over-bg); color: var(--red); }
.badge.ok { background: var(--ok-bg); color: var(--ok-ink); }
.badge.bad { background: var(--bad-bg); color: var(--bad-ink); }
.badge:empty { display: none; }

/* header */
.top { display: flex; align-items: center; justify-content: space-between; gap: 16px; height: 56px; padding: 0 56px; border-bottom: 1px solid var(--hair); }
.top h1 { font-family: var(--serif); font-size: 20px; font-weight: 500; margin: 0; letter-spacing: -0.01em; }
.top nav { display: flex; gap: 26px; font-size: 13.5px; }
.top nav a { text-decoration: none; color: var(--text-2); }
.top nav a:hover { color: var(--ink); }
.top nav a[aria-current] { color: var(--ink); font-weight: 600; }
.top nav a:not([href]) { color: var(--muted); cursor: default; }

/* rail + main */
.body { display: grid; grid-template-columns: 220px minmax(0, 1fr); gap: 72px; padding: 48px 56px 0; max-width: 1440px; margin: 0 auto; }
.rail { position: sticky; top: 24px; align-self: start; display: flex; flex-direction: column; gap: 20px; }
.rail .note { font-size: 13px; color: var(--text-2); }
.steps { border-bottom: 1px solid var(--hair); }
.steps button { display: grid; grid-template-columns: 22px 1fr; gap: 10px; align-items: baseline; width: 100%; text-align: left;
                padding: 12px 0; border: 0; border-top: 1px solid var(--hair); background: none; cursor: pointer; line-height: 1.4; }
.steps .n { font-family: var(--mono); font-size: 12px; color: var(--text-2); }
.steps .t { font-weight: 400; }
.steps .r { font-size: 13px; color: var(--text-2); }
.steps button.on .n, .steps button.on .t { color: var(--ink); font-weight: 600; }
.rail .keys { display: flex; flex-direction: column; gap: 6px; font-size: 12.5px; }
.rail .keys div { display: flex; gap: 8px; align-items: center; color: var(--text-2); }

main { display: flex; flex-direction: column; gap: 72px; min-width: 0; }
section.step { display: flex; flex-direction: column; gap: 22px; }
.step-head { display: flex; flex-direction: column; gap: 8px; }
.step-head h2 { font-family: var(--serif); font-size: 30px; line-height: 1.15; font-weight: 500; letter-spacing: -0.01em; margin: 0; }
.why { font-size: 13.5px; color: var(--text-2); max-width: 760px; }

/* the intro and the sentence */
.lede { font-family: var(--serif); font-size: 34px; line-height: 1.2; letter-spacing: -0.01em; max-width: 900px; }
.situation { padding: 20px 0; border-top: 1px solid var(--hair); border-bottom: 1px solid var(--hair); display: flex; flex-direction: column; gap: 10px; }
.sentence { font-family: var(--serif); font-size: 23px; line-height: 1.65; }
.sentence .mono { font-size: 20px; }
.edit-wrap { position: relative; display: inline; }
button.edit { display: inline; padding: 0 0 1px; border: 0; border-bottom: 1.5px dotted var(--ink); background: none; font: inherit; font-weight: 600; cursor: pointer; white-space: nowrap; line-height: 1.2; }
button.edit.mono { font-family: var(--mono); font-size: 20px; }
button.edit:hover, button.edit[aria-expanded="true"] { border-bottom-style: solid; }
.sentence .badge { margin: 0 2px; position: relative; top: -2px; }
.pop[hidden] { display: none; }
.pop { position: absolute; left: 0; top: calc(100% + 8px); z-index: 5; width: 340px; max-width: calc(100vw - 32px); padding: 14px 16px;
       background: var(--surface); border: 1px solid var(--border); border-radius: 6px; box-shadow: 0 8px 24px rgba(26, 25, 23, 0.10);
       font-family: var(--sans); font-size: 14px; line-height: 1.45; display: flex; flex-direction: column; gap: 8px; }
.pop .lab { display: block; }
.pop label { display: block; }
.pop .row { display: flex; gap: 8px; align-items: center; }
.pop input[type=range] { flex: 1; min-width: 0; accent-color: var(--ink); }
.pop input[type=number] { width: 92px; padding: 4px 6px; border: 1px solid var(--border); border-radius: 4px; background: var(--bg); color: var(--ink); font: inherit; font-family: var(--mono); font-size: 0.9rem; }
.pop select { width: 100%; padding: 6px; border: 1px solid var(--border); border-radius: 4px; background: var(--bg); color: var(--ink); font: inherit; font-size: 0.9rem; }
.pop .hint { font-size: 12.5px; display: block; }
.pop .radios { display: flex; gap: 14px; }
.pop .radios label { display: inline-flex; gap: 6px; align-items: center; }
.pop button.small, button.ghost, button.small { display: inline-flex; align-items: center; height: 30px; padding: 0 10px; border: 1px solid var(--border); border-radius: 4px; background: var(--bg); font-size: 13px; white-space: nowrap; cursor: pointer; }
button.ghost:hover, button.small:hover { border-color: var(--ink); }
.situation .actions { display: flex; align-items: center; gap: 16px; flex-wrap: wrap; }

.situation .actions .spacer { flex: 1; }
/* The situation pinned: once its own place has scrolled past, the sentence
   becomes a one-line bar of the same controls, so an answer below can be read
   while the knob that moves it is still on screen. */
.sit-spacer { height: 0; }
body.pinned .situation { position: fixed; top: 0; left: 0; right: 0; z-index: 8;
  padding: 7px 56px 8px; border-top: 0; border-bottom: 1px solid var(--border);
  background: var(--bg); box-shadow: 0 2px 10px rgba(26, 25, 23, 0.07); }
body.pinned .situation > .actions,
body.pinned .situation > .compare,
body.pinned .situation > .more-assumptions { display: none; }
body.pinned .situation .glue { display: none; }
body.pinned .sentence { font-size: 17px; line-height: 1.3; display: flex; flex-wrap: wrap;
  align-items: baseline; gap: 2px 18px; max-width: 1440px; margin: 0 auto; }
body.pinned .sentence .mono, body.pinned button.edit.mono { font-size: 15px; }
body.pinned .edit-wrap[data-pin-label]::after { content: " " attr(data-pin-label);
  font-family: var(--sans); font-size: 12px; color: var(--muted); margin-left: 4px; }
body.pinned .sentence .badge { top: -1px; }
.controls { position: sticky; top: 0; z-index: 6; background: var(--bg); }
body.pinned .controls { top: 39px; }   /* rides under the pinned sentence, never over it */
body.pinned .controls { box-shadow: 0 1px 0 var(--hair); }

html { scroll-padding-top: 64px; }
@media (max-width: 760px) {
  body.pinned .situation { padding-inline: 16px; }
  body.pinned .sentence { font-size: 15px; gap: 2px 12px; }
}
.term-hint { color: var(--muted); }
details.more-assumptions summary { cursor: pointer; color: var(--text-2); font-size: 13.5px; }
details.more-assumptions .inputs { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 14px 22px; margin-top: 14px; }
.inputs label { display: block; }
.inputs .lab { display: flex; justify-content: space-between; margin-bottom: 2px; }
.inputs .row { display: flex; gap: 8px; align-items: center; }
.inputs input[type=range] { flex: 1; min-width: 0; accent-color: var(--ink); }
.inputs input[type=number] { width: 88px; padding: 4px 6px; border: 1px solid var(--border); border-radius: 4px; background: var(--bg); color: var(--ink); font: inherit; font-family: var(--mono); font-size: 0.9rem; }
.inputs .hint { font-size: 12.5px; display: block; }
.radios label { margin-right: 12px; }
.detail-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 10px; margin-top: 16px; }
.cell { padding: 10px 12px; border: 1px solid var(--hair); border-radius: 6px; }
.cell-title { font-size: 0.8rem; color: var(--text-2); }
.cell-big { font-size: 1.15rem; font-weight: 600; font-family: var(--mono); }
.cell-small { font-size: 0.8rem; color: var(--text-2); }
.coefficients { display: flex; flex-wrap: wrap; gap: 6px 18px; font-size: 0.82rem; color: var(--text-2); margin: 12px 0 4px; }
.coefficients .prov { font-style: italic; padding: 0 5px; border-radius: 3px; }

/* the promise controls */
.controls { display: flex; align-items: center; gap: 24px; flex-wrap: wrap; }
.seg { display: inline-flex; border: 1px solid var(--ink); border-radius: 4px; overflow: hidden; }
.seg button { padding: 7px 14px; border: 0; background: none; font-size: 13.5px; white-space: nowrap; cursor: pointer; }
.seg button + button { border-left: 1px solid var(--ink); }
.seg button.active { background: var(--ink); color: var(--bg); font-weight: 600; }
.slider { display: flex; align-items: center; gap: 12px; flex: 1 1 260px; }
.slider .end { font-size: 12px; color: var(--text-2); white-space: nowrap; }
.slider input[type=range] { flex: 1; min-width: 120px; accent-color: var(--ink); }
.promise-out { display: inline-flex; align-items: center; gap: 6px; height: 32px; padding: 0 10px; border: 1px solid var(--border); border-radius: 4px; }
.promise-out input { width: 4em; border: 0; background: none; font: inherit; font-family: var(--mono); font-weight: 600; text-align: right; padding: 0; }
.promise-out .unit { font-size: 12.5px; color: var(--text-2); white-space: nowrap; }

/* the answer row: three numbers, hairlines between */
.stats { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); border-top: 1px solid var(--hair); border-bottom: 1px solid var(--hair); }
.stat { display: flex; flex-direction: column; gap: 6px; padding: 18px 24px 18px 0; min-width: 0; }
.stat + .stat { padding-left: 24px; border-left: 1px solid var(--hair); }
.stat .lab .badge { margin-left: 4px; }
.num { font-family: var(--serif); font-size: 44px; line-height: 1; font-weight: 500; letter-spacing: -0.02em; font-variant-numeric: tabular-nums; }
.num small { font-family: var(--sans); font-size: 14px; font-weight: 400; letter-spacing: 0; margin-left: 6px; color: var(--text-2); }
.num.small { font-size: 30px; }
.stat p { font-size: 13.5px; }
.stat p:empty { display: none; }
.guard { font-size: 13.5px; color: var(--text-2); }
.guard:empty { display: none; }

/* pictures */
figure { margin: 0; display: flex; flex-direction: column; gap: 10px; }
.plot { padding: 0; }
svg.chart { width: 100%; height: auto; display: block; }
svg .grid { stroke: var(--grid); stroke-width: 1; }
svg .axis-line { stroke: var(--hair); stroke-width: 1; }
svg text.axis { fill: var(--text-2); font-size: 11px; font-family: var(--sans); }
svg text.label { font-size: 11.5px; }
svg text.note { fill: var(--text-2); font-size: 10.5px; }
svg text.note.ink { fill: var(--ink); }
svg .target { stroke: var(--ink); stroke-width: 1.2; stroke-dasharray: 5 5; }
svg .limit { stroke: var(--muted); stroke-width: 1; stroke-dasharray: 2 4; }
svg .line-model { fill: none; stroke: var(--ink); stroke-width: 2; }
svg .line-served { fill: none; stroke: var(--ink); stroke-width: 2; stroke-dasharray: 6 5; }
svg .pt-h0 { fill: var(--blue); stroke: var(--bg); stroke-width: 2; }
svg .pt-h80 { fill: var(--orange); stroke: var(--bg); stroke-width: 2; }
svg .pt-run1 { fill: none; stroke: var(--muted); stroke-width: 1.5; }
svg .pt-now { fill: var(--ink); stroke: var(--bg); stroke-width: 2; }
svg .pt-service { fill: var(--bg); stroke: var(--ink); stroke-width: 2; }
svg [data-tip] { cursor: help; }
ul.legend { list-style: none; padding: 0; margin: 0; font-size: 12px; color: var(--text-2); display: flex; flex-wrap: wrap; gap: 4px 18px; align-items: center; }
ul.legend li { display: inline-flex; gap: 7px; align-items: center; margin: 0; white-space: nowrap; }
ul.legend li[data-tip] { cursor: help; }
ul.legend li[data-tip] .lbl { border-bottom: 1px dotted var(--border); }
ul.legend li[data-tip]:hover .lbl { border-bottom-color: var(--muted); color: var(--ink); }
ul.legend li:focus { outline: 2px solid var(--ink); outline-offset: 2px; border-radius: 3px; }
ul.legend li.caption { margin-left: auto; white-space: normal; text-align: right; max-width: 46%; }
.swatch { display: inline-block; width: 16px; height: 0; border-top: 2px solid var(--ink); flex: none; position: relative; top: -2px; }
.swatch.line-served { border-top-style: dashed; }
.swatch.pt-h0, .swatch.pt-h80, .swatch.pt-run1, .swatch.pt-now, .swatch.pt-service { width: 8px; height: 8px; border: 0; border-radius: 50%; top: 0; }
.swatch.pt-h0 { background: var(--blue); }
.swatch.pt-h80 { background: var(--orange); border-radius: 1px; }
.swatch.pt-run1 { border: 1.5px solid var(--muted); }
.swatch.pt-now { background: var(--ink); }
.swatch.pt-service { border: 2px solid var(--ink); }
.hidden-note { font-size: 12.5px; color: var(--orange); }
.finding { font-size: 12.5px; color: var(--text-2); padding-left: 10px; border-left: 2px solid var(--orange); }
#tooltip { position: absolute; background: var(--ink); color: var(--bg); padding: 8px 10px; border-radius: 4px; font-size: 0.85rem; line-height: 1.4; pointer-events: none; max-width: 360px; z-index: 10; }

/* the trouble flow */
.flow { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px 48px; padding: 18px 0; border-top: 1px solid var(--hair); border-bottom: 1px solid var(--hair); }
.q { display: flex; flex-direction: column; gap: 8px; }
.q .qtext { font-weight: 600; font-size: 13.5px; }
.q .qtext small { font-weight: 400; color: var(--text-2); margin-left: 6px; font-family: var(--mono); font-size: 11.5px; }
.choices { display: flex; flex-wrap: wrap; gap: 6px; }
.choices button { display: inline-flex; align-items: center; height: 30px; padding: 0 12px; border: 1px solid var(--border); border-radius: 4px; background: none; font-size: 13px; white-space: nowrap; cursor: pointer; }
.choices button.active { border-color: var(--ink); background: var(--ink); color: var(--bg); font-weight: 500; }
.changed { grid-column: 1 / -1; color: var(--text-2); font-size: 13.5px; display: flex; gap: 8px; align-items: center; }
#advice { display: flex; flex-direction: column; gap: 14px; }
.symptom { display: flex; flex-direction: column; gap: 10px; }
.symptom h3 { font-family: var(--serif); font-size: 24px; line-height: 1.25; font-weight: 500; margin: 0; }
.symptom ul { padding-left: 18px; margin: 0; }
.symptom ul.main { list-style: none; padding: 0; font-size: 15px; }
.symptom .next, .symptom .knobs { font-size: 13.5px; }
.traps { border-left: 2px solid var(--orange); padding-left: 12px; margin: 6px 0; }
.branch-head { font-size: 11.5px; text-transform: uppercase; letter-spacing: 0.07em; color: var(--text-2); }
.node .evidence { display: inline-block; font-size: 0.72rem; font-weight: 600; color: var(--blue); border: 1px solid var(--blue); border-radius: 3px; padding: 0 4px; margin-right: 6px; vertical-align: middle; }
.node .src { font-size: 0.8rem; color: var(--muted); }
.node.cont, .node.probe { color: var(--text-2); }
details.more, details.expert { margin-top: 4px; }
details summary { cursor: pointer; color: var(--text-2); font-size: 13.5px; }
.cannot .need { font-size: 0.78rem; color: var(--orange); margin-right: 6px; }
.readings { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 8px 16px; padding: 14px 0; margin-top: 8px; border-top: 1px solid var(--hair); }
.reading { display: grid; gap: 2px; font-size: 0.85rem; }
.reading .rname { font-family: var(--mono); font-size: 0.8rem; }
.reading input[type=number], .reading select { padding: 4px 6px; border: 1px solid var(--border); border-radius: 4px; background: var(--bg); color: var(--ink); width: 100%; font: inherit; font-size: 0.9rem; }
.reading .panel { color: var(--muted); font-size: 0.78rem; }
.kindnote { color: var(--orange); }
.derived { display: flex; flex-wrap: wrap; gap: 6px 18px; font-size: 0.85rem; color: var(--text-2); margin: 10px 0; }

/* pin and compare */
.compare { overflow-x: auto; }
.compare table { border-collapse: collapse; width: 100%; font-size: 0.92rem; }
.compare th, .compare td { text-align: left; padding: 6px 10px; border-bottom: 1px solid var(--hair); vertical-align: top; }
.compare thead th { color: var(--text-2); font-weight: 600; }
.compare thead small { display: block; font-weight: 400; color: var(--muted); font-size: 0.78rem; }
.compare tbody th { font-weight: 400; color: var(--text-2); width: 34%; }
.compare td.diff { font-weight: 600; }

/* plain-language terms */
.term { border-bottom: 1px dotted var(--muted); cursor: help; text-decoration: none; }
.term:focus { outline: 2px solid var(--ink); outline-offset: 1px; }

/* foundation */
footer { margin: 72px auto 0; max-width: 1440px; padding: 24px 56px 40px; border-top: 1px solid var(--hair); font-size: 13px; }
footer .grid { display: grid; grid-template-columns: 220px minmax(0, 1fr); gap: 72px; }
footer .lines { display: flex; flex-direction: column; gap: 6px; }
footer .lines .badge { margin-right: 8px; }
footer .fine { margin-top: 18px; padding-top: 14px; border-top: 1px solid var(--hair); color: var(--muted); display: flex; flex-wrap: wrap; gap: 6px 18px; align-items: center; }

/* small screens: the rail goes on top, the three numbers stack */
@media (max-width: 960px) {
  .top, .body, footer { padding-left: 16px; padding-right: 16px; }
  .body { grid-template-columns: 1fr; gap: 28px; padding-top: 28px; }
  .rail { position: static; }
  .rail .note { display: none; }
  .steps { display: flex; border: 0; }
  .steps button { border: 0; padding: 6px 0; grid-template-columns: 16px 1fr; width: auto; flex: 0 1 auto; min-width: 0; margin-right: 18px; }
  .top { height: auto; min-height: 56px; flex-wrap: wrap; padding-block: 10px; }
  .steps .r { display: none; }
  .rail .keys { flex-direction: row; gap: 16px; }
  footer .grid { grid-template-columns: 1fr; gap: 12px; }
  .lede { font-size: 26px; }
  .sentence { font-size: 19px; }
  .sentence .mono, button.edit.mono { font-size: 17px; }
  .step-head h2 { font-size: 24px; }
  .stats { grid-template-columns: 1fr; }
  .stat + .stat { padding-left: 0; border-left: 0; border-top: 1px solid var(--hair); }
  .num { font-size: 36px; }
  .flow { grid-template-columns: 1fr; }
  ul.legend li.caption { margin-left: 0; max-width: none; text-align: left; }
  .top nav { gap: 14px; flex-wrap: wrap; justify-content: flex-end; }
}