:root {
  --bg: #FFF0F7; --surface: #FFFFFF; --surface-2: #FBE0EE; --ink: #2A0A3A; --ink-2: #5C3F6B; --line: #E8C4D8;
  --prim: #E0007A; --prim-ink: #FFFFFF; --acc: #00D4B8; --acc-ink: #2A0A3A; --acc-soft: #CFF8F1; --accent: #B80063;
  --ok: #1f7a4d; --ok-soft: #d8efe3; --warn: #A8420F; --warn-soft: #F9DFD2;
  --font-display: "Avenir Next", "Segoe UI", "Helvetica Neue", Arial, system-ui, sans-serif;
  --font-body: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "SF Mono", "Cascadia Mono", Menlo, Consolas, monospace;
}
@media (prefers-color-scheme: dark) {
  :root { --bg: #1A0828; --surface: #270F3A; --surface-2: #331A4A; --ink: #FFF0F7; --ink-2: #CDB3DA; --line: #4A2B63;
    --prim: #FF3DA5; --prim-ink: #1A0828; --acc: #2EE6CE; --acc-ink: #1A0828; --acc-soft: #0F4540; --accent: #FF7FC2;
    --ok: #5fd39a; --ok-soft: #12382a; --warn: #FF9A6B; --warn-soft: #3D1F12; color-scheme: dark; }
}
/* High contrast: switched on by the header button, or by the device's "increase contrast" setting */
:root[data-contrast="high"] {
  --bg: #000000; --surface: #000000; --surface-2: #000000; --ink: #FFFFFF; --ink-2: #FFFFFF; --line: #FFFFFF;
  --prim: #00D4B8; --prim-ink: #000000; --acc: #00D4B8; --acc-ink: #000000; --acc-soft: #000000; --accent: #00D4B8;
  --ok: #FFFFFF; --ok-soft: #000000; --warn: #FFFFFF; --warn-soft: #000000; color-scheme: dark;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--ink); font-family: var(--font-body); font-size: 16px; line-height: 1.6; }
a { color: var(--accent); text-underline-offset: 2px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 3px solid var(--accent); outline-offset: 2px; }
.wrap { max-width: 1120px; margin: 0 auto; padding-inline: 16px; }
.narrow { max-width: 720px; }
header.site { border-bottom: 1px solid var(--line); background: var(--surface); }
header.site .wrap { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 8px 24px; padding-block: 12px; }
.brand { font-family: var(--font-display); font-weight: 800; font-size: 22px; letter-spacing: -0.02em; color: var(--ink); text-decoration: none; }
.brand b { background: var(--acc); color: var(--acc-ink); border-radius: 5px; padding: 0 7px; margin-left: 3px; display: inline-block; line-height: 1.2; }
nav.main { display: flex; flex-wrap: wrap; gap: 4px 18px; font-size: 15px; }
nav.main a { color: var(--ink); text-decoration: none; padding: 4px 0; border-bottom: 3px solid transparent; }
nav.main a:hover, nav.main a[aria-current="page"] { border-bottom: 3px solid var(--acc); }
.disclose { background: var(--acc); color: var(--acc-ink); font-size: 14px; }
.disclose a { color: var(--acc-ink); font-weight: 600; }
.disclose .wrap { padding-block: 8px; }
main { padding-block: 32px 56px; }
h1, h2, h3 { font-family: var(--font-display); line-height: 1.15; letter-spacing: -0.01em; text-wrap: balance; }
h1 { font-size: clamp(30px, 5.5vw, 46px); margin: 0 0 12px; }
h2 { font-size: clamp(22px, 3.5vw, 28px); margin: 40px 0 8px; }
h3 { font-size: 18px; margin: 24px 0 4px; }
p { margin: 0 0 14px; }
.lede { font-size: 19px; color: var(--ink-2); max-width: 60ch; }
.prose { max-width: 70ch; }
.prose ul, .prose ol { padding-left: 22px; margin: 0 0 14px; }
.prose li { margin-bottom: 6px; }
.btn { display: inline-block; font-weight: 700; background: var(--prim); color: var(--prim-ink); text-decoration: none; padding: 12px 20px; border-radius: 4px; border: 2px solid var(--ink); }
.btn:hover { filter: brightness(1.08); }
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 14px; margin-top: 16px; }
.card { display: block; background: var(--surface); border: 1px solid var(--line); border-top: 5px solid var(--prim); border-radius: 6px; padding: 16px; color: var(--ink); text-decoration: none; min-width: 0; }
a.card:hover { border-color: var(--prim); }
.card h3 { margin: 0 0 4px; font-size: 18px; }
.card p { margin: 0; color: var(--ink-2); font-size: 15px; }
.kicker { font-family: var(--font-mono); font-size: 12px; letter-spacing: 0.08em; text-transform: uppercase; font-weight: 700; color: var(--accent); margin-bottom: 8px; display: inline-block; }
.hero { padding-block: 16px 8px; }
.callout { background: var(--surface); border: 1px solid var(--line); border-left: 6px solid var(--prim); padding: 14px 16px; border-radius: 4px; margin: 20px 0; max-width: 70ch; }
.callout p:last-child { margin: 0; }
.table-wrap { overflow-x: auto; margin: 16px 0; }
table { border-collapse: collapse; width: 100%; font-size: 15px; background: var(--surface); }
th, td { text-align: left; padding: 8px 10px; border-top: 1px solid var(--line); vertical-align: top; }
th { font-weight: 600; color: var(--ink-2); border-top: 0; font-size: 13px; text-transform: uppercase; letter-spacing: 0.04em; }
td.num, th.num { text-align: right; font-family: var(--font-mono); font-variant-numeric: tabular-nums; white-space: nowrap; }
.meta { color: var(--ink-2); font-size: 14px; margin-bottom: 20px; }
.crumbs { font-size: 14px; color: var(--ink-2); margin-bottom: 16px; }
.crumbs a { color: var(--ink-2); }
footer.site { border-top: 1px solid var(--line); background: var(--surface); font-size: 14px; color: var(--ink-2); }
footer.site .wrap { padding-block: 24px; display: flex; flex-direction: column; gap: 10px; }
footer.site nav { display: flex; flex-wrap: wrap; gap: 6px 18px; }
footer.site a { color: var(--ink-2); }
.placeholder { background: var(--warn-soft); padding: 0 4px; border-radius: 2px; }
/* ----- tool ----- */
.grid { display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr); gap: 20px; align-items: start; }
@media (max-width: 820px) { .grid { grid-template-columns: minmax(0, 1fr); } }
.col { display: flex; flex-direction: column; gap: 16px; min-width: 0; }
.panel { background: var(--surface); border: 1px solid var(--line); border-radius: 6px; padding: 16px; min-width: 0; }
.panel h2 { margin: 0 0 4px; font-size: 19px; }
.sub { color: var(--ink-2); font-size: 14px; margin: 0 0 12px; }
.chips { display: flex; flex-wrap: wrap; gap: 8px; }
.chip { font: inherit; font-size: 14px; border: 1px solid var(--line); background: var(--surface-2); color: var(--ink); padding: 7px 12px; border-radius: 4px; cursor: pointer; }
.chip:hover { border-color: var(--prim); }
.chip[aria-pressed="true"] { background: var(--prim); color: var(--prim-ink); border-color: var(--prim); font-weight: 600; }
.devices { display: flex; flex-direction: column; }
.row { display: grid; grid-template-columns: minmax(0, 1fr) auto auto; gap: 10px 14px; align-items: center; padding: 9px 0; border-top: 1px solid var(--line); }
.row:first-child { border-top: 0; }
.row.off .name { color: var(--ink-2); }
.name { font-weight: 500; min-width: 0; }
.name small { display: block; font-family: var(--font-mono); font-size: 12px; color: var(--ink-2); font-weight: 400; }
.stepper { display: inline-flex; align-items: center; border: 1px solid var(--line); border-radius: 4px; overflow: hidden; }
.stepper button { font: inherit; width: 34px; height: 34px; border: 0; background: var(--surface-2); color: var(--ink); cursor: pointer; font-size: 16px; }
.stepper button:hover { background: var(--acc-soft); }
.stepper output { min-width: 30px; text-align: center; font-family: var(--font-mono); font-variant-numeric: tabular-nums; }
.hrs { display: inline-flex; align-items: center; gap: 6px; font-size: 13px; color: var(--ink-2); }
input[type="number"], select { font: inherit; font-family: var(--font-mono); background: var(--surface); color: var(--ink); border: 1px solid var(--line); border-radius: 4px; padding: 5px 6px; width: 64px; }
select { width: 100%; font-family: var(--font-body); padding: 8px; }
.settings { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 12px; }
.field label { display: block; font-size: 12px; font-family: var(--font-mono); text-transform: uppercase; letter-spacing: 0.06em; color: var(--ink-2); margin-bottom: 4px; }
.field input[type="number"] { width: 100%; padding: 8px; }
.stats { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px 16px; margin: 0 0 14px; }
.stat dt { font-size: 12px; color: var(--ink-2); }
.stat dd { margin: 0; font-family: var(--font-mono); font-size: 18px; font-variant-numeric: tabular-nums; }
.bars { display: flex; flex-direction: column; gap: 6px; }
.bar { display: grid; grid-template-columns: 110px minmax(0, 1fr) 64px; gap: 8px; align-items: center; font-size: 13px; }
.bar .track { height: 8px; background: var(--surface-2); border-radius: 2px; overflow: hidden; }
.bar .fill { height: 100%; background: var(--prim); }
.bar span:last-child { text-align: right; font-family: var(--font-mono); font-variant-numeric: tabular-nums; color: var(--ink-2); }
.check { display: flex; gap: 10px; align-items: flex-start; padding: 8px 10px; border-radius: 4px; font-size: 14px; }
.check.warn { background: var(--warn-soft); }
.check b { font-family: var(--font-mono); font-size: 11px; text-transform: uppercase; letter-spacing: 0.06em; padding: 2px 6px; border-radius: 3px; flex: none; margin-top: 2px; background: var(--warn); color: var(--surface); }
.opts { display: flex; flex-direction: column; gap: 12px; }
.opt { border: 1px solid var(--line); border-radius: 6px; padding: 14px; background: var(--bg); min-width: 0; }
.opt h3 { font-size: 20px; margin: 8px 0 4px; }
.opt h3 em { font-style: normal; color: var(--accent); }
.tags { display: flex; flex-wrap: wrap; gap: 6px; }
.tag { font-family: var(--font-mono); font-size: 11px; letter-spacing: 0.05em; text-transform: uppercase; background: var(--acc); color: var(--acc-ink); padding: 2px 7px; border-radius: 3px; font-weight: 700; }
.spec { margin: 0; font-family: var(--font-mono); font-size: 13px; color: var(--ink-2); font-variant-numeric: tabular-nums; }
.note { margin: 8px 0 0; font-size: 13px; color: var(--ink-2); }
.links { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; margin-top: 12px; }
.lk { display: block; text-align: center; padding: 9px 8px; border-radius: 4px; border: 2px solid var(--prim); font-weight: 600; font-size: 14px; color: var(--ink); text-decoration: none; background: var(--acc-soft); }
.lk:hover { background: var(--prim); color: var(--prim-ink); }
details { margin-top: 12px; font-size: 15px; }
summary { cursor: pointer; font-weight: 500; }
.work { font-family: var(--font-mono); font-size: 12.5px; color: var(--ink-2); margin: 8px 0 0; padding-left: 18px; display: flex; flex-direction: column; gap: 4px; }
.method p { margin: 8px 0 0; color: var(--ink-2); font-size: 14px; max-width: 62ch; }
.foot { font-size: 13px; color: var(--ink-2); max-width: 80ch; margin-top: 8px; }
table.range { font-family: var(--font-mono); font-size: 13px; }
table.range td, table.range th { white-space: nowrap; }

/* header toggle */
.hd-right { display: flex; flex-wrap: wrap; align-items: center; gap: 8px 20px; }
.hc-toggle { font: inherit; font-size: 14px; font-weight: 600; display: inline-flex; align-items: center; gap: 8px; background: var(--surface); color: var(--ink); border: 2px solid var(--ink); border-radius: 4px; padding: 3px 12px; cursor: pointer; }
.hc-toggle::before { content: ""; width: 13px; height: 13px; border-radius: 50%; border: 2px solid currentColor; background: linear-gradient(90deg, currentColor 50%, transparent 50%); flex: none; }
.hc-toggle[aria-pressed="true"] { background: var(--prim); color: var(--prim-ink); border-color: var(--prim); }
/* high contrast extras */
:root[data-contrast="high"] a { text-decoration: underline; text-decoration-thickness: 2px; }
:root[data-contrast="high"] .btn, :root[data-contrast="high"] nav.main a, :root[data-contrast="high"] a.card, :root[data-contrast="high"] .brand { text-decoration: none; }
:root[data-contrast="high"] nav.main a { text-decoration: underline; }
:root[data-contrast="high"] header.site, :root[data-contrast="high"] footer.site, :root[data-contrast="high"] .disclose { border-color: #fff; border-style: solid; }
:root[data-contrast="high"] header.site { border-bottom-width: 3px; }
:root[data-contrast="high"] footer.site { border-top-width: 3px; }
:root[data-contrast="high"] .panel, :root[data-contrast="high"] .card, :root[data-contrast="high"] .opt, :root[data-contrast="high"] .callout, :root[data-contrast="high"] .stepper, :root[data-contrast="high"] .check, :root[data-contrast="high"] input, :root[data-contrast="high"] select, :root[data-contrast="high"] .chip, :root[data-contrast="high"] .lk { border: 2px solid #fff; }
:root[data-contrast="high"] .card { border-top-width: 6px; }
:root[data-contrast="high"] .callout { border-left-width: 8px; }
:root[data-contrast="high"] .bar .track { border: 1px solid #fff; }
:root[data-contrast="high"] .chip[aria-pressed="true"], :root[data-contrast="high"] .hc-toggle[aria-pressed="true"] { background: var(--prim); color: #000; border-color: #fff; }
:root[data-contrast="high"] .check b { background: #fff; color: #000; }
:root[data-contrast="high"] :focus-visible { outline: 4px solid #fff; outline-offset: 3px; box-shadow: 0 0 0 7px #000; }
:root[data-contrast="high"] .placeholder { background: #fff; color: #000; }

/* unit pages */
.small { font-size: 14px; color: var(--ink-2); }
ul.plain { list-style: none; padding: 0; margin: 12px 0; }
ul.plain li { padding: 10px 0; border-bottom: 1px solid var(--line); }
ul.plain .small { display: block; font-family: var(--font-mono); }
.opt h3 a { color: inherit; text-decoration: none; }
.opt h3 a:hover { text-decoration: underline; }
table th[scope="row"] { text-align: left; font-weight: 600; }

/* playful doodles */
.doodle { display: block; overflow: visible; }
.doodle .ink { fill: none; stroke: var(--ink); stroke-width: 3.5px; stroke-linecap: round; stroke-linejoin: round; vector-effect: non-scaling-stroke; }
.doodle .thin { stroke-width: 2.5px; }
.doodle .f-a { fill: var(--prim); }
.doodle .f-b { fill: var(--acc); }
.doodle .f-c { fill: var(--surface); }
.doodle { filter: url(#rough); }
.top { display: grid; grid-template-columns: 1fr auto; gap: 24px; align-items: center; }
.hero-art { width: 210px; height: auto; margin-right: 8px; }
.spark-wrap { display: flex; justify-content: center; margin: 40px 0 0; }
.spark-row { width: 220px; height: auto; }
.ico { width: 34px; height: 34px; flex: none; }
.chip { display: inline-flex; align-items: center; gap: 8px; padding-block: 5px; }
.chip .ico .ink { stroke-width: 2.2px; }
.chip .ico .thin { stroke-width: 1.6px; }
.chip[aria-pressed="true"] .ico .f-a, .chip[aria-pressed="true"] .ico .f-b { fill: var(--surface); }
.chip[aria-pressed="true"] .ico .ink { stroke: var(--prim-ink); }
@media (max-width: 640px) { .top { grid-template-columns: 1fr; } .hero-art { width: 130px; margin: 0 0 8px; order: -1; } }
@keyframes twinkle { 0%, 100% { transform: scale(1) rotate(0); } 50% { transform: scale(1.08) rotate(4deg); } }
.hero-art, .spark-row { transform-origin: 50% 50%; }
@media (prefers-reduced-motion: no-preference) { .hero-art { animation: twinkle 5s ease-in-out infinite; } }
:root[data-contrast="high"] .doodle .ink { stroke: #fff; }
:root[data-contrast="high"] .doodle .f-a, :root[data-contrast="high"] .doodle .f-b { fill: #00D4B8; }
:root[data-contrast="high"] .doodle .f-c { fill: #000; }

/* plain-English help */
.hint { display: block; font-size: 12px; color: var(--ink-2); line-height: 1.3; margin-top: 2px; }
th small { display: block; font-family: var(--font-body); font-size: 11px; font-weight: 400; text-transform: none; letter-spacing: 0; color: var(--ink-2); }
.keyline { font-size: 14px; color: var(--ink-2); margin: 6px 0 12px; }
.key { background: var(--acc-soft); border: 2px solid var(--ink); border-radius: 6px; padding: 14px 18px; margin: 20px 0; }
.key h2 { font-size: 18px; margin: 0 0 8px; }
.key dl { margin: 0; }
.key dt { font-weight: 700; margin-top: 10px; }
.key dd { margin: 2px 0 0; }
.key p { margin: 8px 0 0; }
.remind { background: var(--surface-2); border-left: 5px solid var(--prim); padding: 10px 14px; margin: 16px 0; }
td.means { color: var(--ink-2); font-size: 14px; min-width: 190px; }
:root[data-contrast="high"] .key { background: #000; border-color: #fff; }
:root[data-contrast="high"] .remind { background: #000; border-left-color: #00D4B8; }

/* inputs vs results: dark where you enter, light where you read */
.zone-label { font-family: var(--font-mono); font-size: 12px; letter-spacing: 0.06em; text-transform: uppercase; font-weight: 700; display: flex; align-items: center; gap: 10px; flex-wrap: wrap; color: var(--ink-2); }
.zone-label span { display: inline-block; padding: 5px 12px; border-radius: 999px; font-size: 13px; }
.zl-in span { background: var(--prim); color: var(--prim-ink); }
.zl-out span { background: var(--acc); color: var(--acc-ink); }
.col.inputs { background: #2A0A3A; border-radius: 10px; padding: 16px; border: 2px solid #2A0A3A;
  --surface: #3B1752; --surface-2: #4C2466; --bg: #2E0F43; --ink: #FFF0F7; --ink-2: #D9BDE6; --line: #6A3F86;
  --prim: #FF3DA5; --prim-ink: #1A0828; --acc: #2EE6CE; --acc-ink: #1A0828; --acc-soft: #0F4540; --accent: #FF7FC2; --warn: #FF9A6B; --warn-soft: #3D1F12;
  color: var(--ink); }
.col.inputs .panel { border: 1px solid var(--line); border-top: 6px solid var(--prim); }
.col.results { background: #FFFFFF; border-radius: 10px; padding: 16px; border: 2px solid var(--acc);
  --surface: #FFF0F7; --surface-2: #FBE0EE; --bg: #FFFFFF; --ink: #2A0A3A; --ink-2: #5C3F6B; --line: #E8C4D8;
  --prim: #E0007A; --prim-ink: #FFFFFF; --acc: #00D4B8; --acc-ink: #2A0A3A; --acc-soft: #CFF8F1; --accent: #B80063; --warn: #A8420F; --warn-soft: #F9DFD2;
  color: var(--ink); }
.col.results .panel { border: 1px solid var(--line); border-top: 6px solid var(--acc); }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .col.inputs { background: #2A0A3A; border-color: var(--prim); }
}
:root[data-contrast="high"] .col.inputs { background: #000; border-color: #fff;
  --surface: #000; --surface-2: #000; --bg: #000; --ink: #fff; --ink-2: #fff; --line: #fff; --prim: #00D4B8; --prim-ink: #000; --acc: #00D4B8; --acc-ink: #000; --acc-soft: #000; --accent: #00D4B8; --warn: #fff; }
:root[data-contrast="high"] .col.inputs .panel { border: 2px solid #fff; }
:root[data-contrast="high"] .col.results { background: #fff; border-color: #fff;
  --surface: #fff; --surface-2: #fff; --bg: #fff; --ink: #000; --ink-2: #000; --line: #000; --prim: #000; --prim-ink: #fff; --acc: #00D4B8; --acc-ink: #000; --acc-soft: #fff; --accent: #000; --warn: #000; }
:root[data-contrast="high"] .col.results .panel { border: 2px solid #000; }
:root[data-contrast="high"] .col.results .doodle .ink { stroke: #000; }
@media (max-width: 860px) { .col.results { margin-top: 8px; } }

/* homepage content and unit illustrations */
.lede2 { color: var(--ink-2); margin: 0 0 8px; max-width: 62ch; }
.prose-block { max-width: 760px; margin: 48px 0 0; }
.prose-block h2 { margin-bottom: 10px; }
.prose-block h3 { font-size: 17px; margin: 22px 0 4px; }
.prose-block p, .prose-block li { max-width: 68ch; }
ul.ticks { list-style: none; padding: 0; margin: 14px 0; display: grid; gap: 10px; }
ul.ticks li { padding-left: 30px; position: relative; }
ul.ticks li::before { content: "⚡"; position: absolute; left: 0; top: 0; color: var(--prim); font-weight: 700; }
ol.steps { padding-left: 22px; display: grid; gap: 10px; }
.unit-head { display: grid; grid-template-columns: 1fr auto; gap: 24px; align-items: center; }
.unit-fig { margin: 0; text-align: center; }
.unit-art { width: 230px; height: auto; margin: 0 auto; }
@media (max-width: 700px) { .unit-head { grid-template-columns: 1fr; } .unit-art { width: 170px; } }
.unit-fig figcaption { max-width: 240px; margin: 6px auto 0; }
.stock { border-left: 4px solid var(--warn); padding-left: 10px; }