/* CalcPit — single stylesheet, no build step, no webfont.
   System fonts only: zero third-party request, zero FOUT, zero layout shift. */

:root {
  --bg: #f6f7f9;
  --card: #ffffff;
  --ink: #14171c;
  --ink-soft: #5a6270;
  /* 4.8:1 on --bg. Anything lighter fails WCAG AA for the help text and
     breadcrumbs that use it — and those are read on a phone, outdoors. */
  --ink-faint: #6b7280;
  --line: #e3e7ec;
  --line-strong: #cfd6de;
  --accent: #c2410c;
  --accent-hover: #9a3412;
  --accent-soft: #fff3ec;
  --accent-line: #f6c9ae;
  --warn: #b45309;
  --radius: 10px;
  --radius-lg: 14px;
  --shadow: 0 1px 2px rgb(16 24 40 / 4%), 0 2px 6px rgb(16 24 40 / 5%);
  --measure: 46rem;
  --measure-wide: 66rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1216;
    --card: #171b21;
    --ink: #e9edf2;
    --ink-soft: #9aa4b2;
    --ink-faint: #79828f;
    --line: #262c35;
    --line-strong: #333b46;
    --accent: #fb923c;
    --accent-hover: #fdba74;
    --accent-soft: #241610;
    --accent-line: #4a2a15;
    --warn: #fbbf24;
    --shadow: 0 1px 2px rgb(0 0 0 / 30%), 0 2px 6px rgb(0 0 0 / 25%);
  }
}

*, *::before, *::after { box-sizing: border-box; }

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: 1.5rem;
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition-duration: 0s !important; animation-duration: 0s !important; }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.65 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  -webkit-font-smoothing: antialiased;
}

main {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 1.5rem 1.15rem 4rem;
}
main.wide { max-width: var(--measure-wide); }

h1 {
  font-size: clamp(1.65rem, 1.35rem + 1.4vw, 2.1rem);
  line-height: 1.15; margin: 0 0 .5rem; letter-spacing: -.022em;
}
h2 { font-size: 1.2rem; margin: 2.5rem 0 .85rem; letter-spacing: -.012em; }
h3 { font-size: 1rem; margin: 1.4rem 0 .45rem; }
p { margin: 0 0 .95rem; }

a { color: var(--accent); text-underline-offset: .15em; }
a:hover { color: var(--accent-hover); }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 3px;
}

.lede { color: var(--ink-soft); font-size: 1.05rem; margin-bottom: 1.4rem; }
.note { font-size: .85rem; color: var(--ink-faint); }

.skip {
  position: absolute; left: -9999px;
  background: var(--card); color: var(--ink);
  padding: .6rem .9rem; border: 1px solid var(--line); border-radius: var(--radius);
}
.skip:focus { left: .75rem; top: .75rem; z-index: 10; }

/* ---------- chrome ---------- */

.site-header {
  background: var(--card);
  border-bottom: 1px solid var(--line);
}
.site-header .bar {
  display: flex; align-items: center; justify-content: space-between; gap: 1rem;
  max-width: var(--measure-wide); margin: 0 auto; padding: .8rem 1.15rem;
}
.brand {
  display: inline-flex; align-items: center; gap: .5rem;
  font-weight: 700; font-size: 1.05rem; letter-spacing: -.02em;
  text-decoration: none; color: var(--ink);
}
.brand .mark { color: var(--accent); flex: none; border-radius: 7px; }
.site-header nav a {
  font-size: .9rem; font-weight: 500; text-decoration: none;
  color: var(--ink-soft); padding: .35rem .1rem;
}
.site-header nav a:hover { color: var(--accent); }

.crumbs { font-size: .8rem; color: var(--ink-faint); margin-bottom: .9rem; }
.crumbs a { color: var(--ink-soft); text-decoration: none; }
.crumbs a:hover { color: var(--accent); text-decoration: underline; }
.crumbs .sep { margin: 0 .35rem; color: var(--line-strong); }

.site-footer {
  background: var(--card);
  border-top: 1px solid var(--line);
  margin-top: 3rem;
}
.foot-inner {
  max-width: var(--measure-wide); margin: 0 auto; padding: 2rem 1.15rem 2.5rem;
}
.foot-nav h2 {
  font-size: .75rem; text-transform: uppercase; letter-spacing: .08em;
  color: var(--ink-faint); margin: 0 0 .75rem;
}
.foot-nav ul {
  list-style: none; margin: 0 0 1.5rem; padding: 0;
  display: grid; gap: .35rem .5rem;
  grid-template-columns: repeat(auto-fill, minmax(11rem, 1fr));
}
.foot-nav a { font-size: .9rem; text-decoration: none; color: var(--ink-soft); }
.foot-nav a:hover { color: var(--accent); }
.disclaimer {
  margin: 0; padding-top: 1.25rem; border-top: 1px solid var(--line);
  font-size: .8rem; color: var(--ink-faint); max-width: 44rem;
}

/* ---------- page head ---------- */

.badge {
  display: inline-block; margin-bottom: .7rem;
  font-size: .72rem; font-weight: 600; text-transform: uppercase; letter-spacing: .07em;
  text-decoration: none;
  color: var(--accent); background: var(--accent-soft);
  border: 1px solid var(--accent-line);
  padding: .2rem .5rem; border-radius: 100px;
}
.badge:hover { border-color: var(--accent); }

/* ---------- the calculator: above the fold, always ---------- */

.calculator {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  overflow: hidden;
}
.calc-fields { padding: 1.15rem 1.15rem 1.25rem; }

.fields { display: grid; gap: .9rem; }
@media (min-width: 34rem) {
  .fields { grid-template-columns: repeat(auto-fit, minmax(10rem, 1fr)); }
}

.field label {
  display: block; font-size: .74rem; font-weight: 600;
  color: var(--ink-soft); margin-bottom: .35rem;
  text-transform: uppercase; letter-spacing: .06em;
}

.control { display: flex; align-items: stretch; }

.control input {
  flex: 1; min-width: 0;
  font: inherit; font-variant-numeric: tabular-nums;
  padding: .62rem .7rem;
  color: var(--ink); background: var(--bg);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius) 0 0 var(--radius);
  -moz-appearance: textfield;
  transition: border-color .12s, box-shadow .12s;
}
.control input::-webkit-outer-spin-button,
.control input::-webkit-inner-spin-button { -webkit-appearance: none; margin: 0; }
.control input:hover { border-color: var(--ink-faint); }
.control input:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
  position: relative; z-index: 1;
}
.control input:not(:placeholder-shown):invalid { border-color: var(--warn); }

.control .unit {
  display: flex; align-items: center; padding: 0 .7rem;
  font-size: .85rem; font-weight: 500; color: var(--ink-faint);
  background: var(--bg);
  border: 1px solid var(--line-strong); border-left: 0;
  border-radius: 0 var(--radius) var(--radius) 0;
  white-space: nowrap;
}
.control .unit:empty { display: none; }
.control:has(.unit:empty) input { border-radius: var(--radius); }

.help { display: block; font-size: .78rem; color: var(--ink-faint); margin-top: .35rem; }

/* Results keep their height whether or not a value is shown — no layout shift. */
.results {
  background: var(--accent-soft);
  border-top: 1px solid var(--accent-line);
  padding: 1rem 1.15rem 1.1rem;
}

.result {
  display: flex; align-items: baseline; gap: .6rem;
  font-size: .9rem; color: var(--ink-soft);
  padding: .28rem 0;
}
.result + .result { border-top: 1px solid var(--accent-line); }
.result-label { flex: 1; }
.result-value { font-variant-numeric: tabular-nums; font-weight: 600; color: var(--ink); }
.result-unit { color: var(--ink-faint); }

.result.primary {
  display: block; padding: 0 0 .7rem; margin-bottom: .3rem;
  border-bottom: 1px solid var(--accent-line);
}
.result.primary + .result { border-top: 0; }
.result.primary .result-label {
  display: block; font-size: .72rem; font-weight: 600;
  text-transform: uppercase; letter-spacing: .07em; color: var(--ink-soft);
  margin-bottom: .1rem;
}
.result.primary .result-value {
  font-size: clamp(2rem, 1.6rem + 1.8vw, 2.6rem); line-height: 1.05;
  font-weight: 700; letter-spacing: -.03em; color: var(--accent);
}
.result.primary .result-unit {
  font-size: 1.05rem; font-weight: 600; color: var(--accent); margin-left: .15rem;
}

/* ---------- content below ---------- */

.warning {
  margin-top: 1.15rem; padding: .8rem .95rem .8rem 1rem;
  border: 1px solid var(--line); border-left: 3px solid var(--warn);
  border-radius: var(--radius); background: var(--card);
  font-size: .875rem; color: var(--ink-soft);
}

.materials { margin-top: 1.75rem; }
.material-list { margin: 0 0 .8rem; padding-left: 1.15rem; }
.material-list li { margin-bottom: .3rem; }

.leadgen {
  margin-top: 1.75rem; padding: 1.15rem;
  border: 1px solid var(--accent-line); border-radius: var(--radius-lg);
  background: var(--accent-soft);
}
.leadgen h2 { margin-top: 0; }
.cta {
  display: inline-block; margin-top: .4rem; padding: .65rem 1.2rem;
  background: var(--accent); color: #fff; font-weight: 600;
  text-decoration: none; border: 0; border-radius: var(--radius);
  font-size: 1rem; cursor: pointer;
}
.cta:hover { background: var(--accent-hover); color: #fff; }

.explainer, .depth, .faq, .related { border-top: 1px solid var(--line); padding-top: .25rem; }
.explainer { margin-top: 2.25rem; }
.depth ul { padding-left: 1.15rem; }
.depth ul li { margin-bottom: .3rem; }

.formula code {
  display: block; padding: .75rem .85rem;
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius);
  font-size: .875rem; overflow-x: auto; white-space: nowrap;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

.faq-item { border-bottom: 1px solid var(--line); }
.faq-item summary {
  cursor: pointer; padding: .85rem 0; font-weight: 600; list-style: none;
  display: flex; justify-content: space-between; align-items: center; gap: 1rem;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: ""; flex: none; width: .55rem; height: .55rem;
  border-right: 2px solid var(--ink-faint); border-bottom: 2px solid var(--ink-faint);
  transform: rotate(45deg) translate(-2px, -2px);
  transition: transform .15s;
}
.faq-item[open] summary::after { transform: rotate(225deg) translate(-2px, -2px); }
.faq-item summary:hover { color: var(--accent); }
.faq-body { padding-bottom: .9rem; color: var(--ink-soft); }
.faq-body p { margin: 0; }

/* ---------- listing tiles ---------- */

.tiles {
  list-style: none; margin: 0; padding: 0;
  display: grid; gap: .6rem;
  grid-template-columns: repeat(auto-fill, minmax(15rem, 1fr));
}
.tile {
  display: block; height: 100%; padding: .8rem .9rem;
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); text-decoration: none; color: var(--ink);
  transition: border-color .12s, box-shadow .12s, transform .12s;
}
.tile:hover {
  border-color: var(--accent); box-shadow: var(--shadow);
  transform: translateY(-1px); color: var(--ink);
}
.tile .t { display: block; font-weight: 600; line-height: 1.3; }
.tile .s { display: block; font-size: .8rem; color: var(--ink-faint); margin-top: .15rem; }

.cat-block { margin-top: 2.5rem; scroll-margin-top: 1.5rem; }
.cat-head {
  display: flex; align-items: baseline; gap: .6rem;
  margin: 0 0 .85rem; font-size: 1.15rem; letter-spacing: -.012em;
}
.cat-head .count { font-size: .8rem; font-weight: 400; color: var(--ink-faint); }

/* Index filter — injected by script, so it never appears without JS to run it. */
.filter { margin: 1.5rem 0 .5rem; }
.filter input {
  width: 100%; font: inherit; padding: .7rem .9rem;
  color: var(--ink); background: var(--card);
  border: 1px solid var(--line-strong); border-radius: var(--radius);
}
.filter input:focus {
  outline: none; border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}
.filter-empty { color: var(--ink-soft); padding: 1.5rem 0; }
[hidden] { display: none !important; }

/* ---------- tables ---------- */

.table-wrap { overflow-x: auto; margin: 0 0 1.2rem; }
table {
  border-collapse: collapse; width: 100%; font-size: .9rem;
  background: var(--card); border: 1px solid var(--line);
  border-radius: var(--radius); overflow: hidden;
}
th, td { padding: .55rem .7rem; text-align: left; border-bottom: 1px solid var(--line); }
th {
  font-size: .72rem; text-transform: uppercase; letter-spacing: .06em;
  color: var(--ink-soft); background: var(--bg); white-space: nowrap;
}
tbody tr:last-child td { border-bottom: 0; }
td.num, th.num { text-align: right; font-variant-numeric: tabular-nums; }

.foot-meta ul { grid-template-columns: repeat(auto-fill, minmax(7rem, 1fr)); }

.sr-only {
  position: absolute; width: 1px; height: 1px; overflow: hidden;
  clip: rect(0 0 0 0); clip-path: inset(50%); white-space: nowrap;
}

/* ---------- home ---------- */

.hero { padding: .5rem 0 1.5rem; }
.hero h1 { max-width: 20ch; }
.hero .lede { max-width: 52ch; font-size: 1.1rem; }
.hero-actions { display: flex; flex-wrap: wrap; gap: .6rem; margin-top: 1.2rem; }
.btn-ghost {
  display: inline-block; padding: .65rem 1.2rem;
  border: 1px solid var(--line-strong); border-radius: var(--radius);
  background: var(--card); color: var(--ink); font-weight: 600; text-decoration: none;
}
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); }

.trust {
  display: grid; gap: .9rem; margin: 2.5rem 0 0;
  grid-template-columns: repeat(auto-fit, minmax(13rem, 1fr));
  list-style: none; padding: 0;
}
.trust li {
  padding: .95rem 1rem; background: var(--card);
  border: 1px solid var(--line); border-radius: var(--radius);
}
.trust strong { display: block; margin-bottom: .2rem; }
.trust span { font-size: .875rem; color: var(--ink-soft); }