/* furnacefiltersize.com — 2026 reference, not a shop */
:root {
  --bg: #f4f1ea;
  --bg-2: #ebe6db;
  --paper: #fffcf6;
  --ink: #1c1b18;
  --muted: #5c5a54;
  --line: #d4cfc3;
  --link: #1e3d5c;
  --link-hover: #0f2438;
  --accent: #6b3a28;
  --warn-bg: #f6ead4;
  --warn-ink: #5c3d0e;
  --draft-bg: #efe6c8;
  --ok-bg: #e4eee6;
  --max: 46rem;
  --wide: 72rem;
  --sans: "Segoe UI", system-ui, -apple-system, "Helvetica Neue", Helvetica, Arial, sans-serif;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, "Times New Roman", serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}
*, *::before, *::after { box-sizing: border-box; }
html { font-size: 18px; scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--serif);
  line-height: 1.55;
}
img { max-width: 100%; height: auto; }
a { color: var(--link); text-underline-offset: 0.15em; }
a:hover { color: var(--link-hover); }
a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible {
  outline: 2px solid var(--link);
  outline-offset: 2px;
}
.skip {
  position: absolute; left: -999px; top: 0;
  background: var(--paper); padding: 0.5rem 1rem; z-index: 9;
}
.skip:focus { left: 0.5rem; top: 0.5rem; }
.site-header {
  background: var(--paper);
  border-bottom: 1px solid var(--line);
  font-family: var(--sans);
}
.site-header .inner {
  max-width: var(--wide);
  margin: 0 auto;
  padding: 0.7rem 1rem 0.85rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem 1.25rem;
}
.wordmark {
  font-weight: 650;
  color: var(--ink);
  text-decoration: none;
  letter-spacing: -0.02em;
  font-size: 1.02rem;
}
.wordmark span { font-weight: 400; color: var(--muted); }
.nav-wrap { margin-left: auto; }
.nav-wrap > summary {
  list-style: none;
  cursor: pointer;
  font-size: 0.92rem;
}
.nav-wrap > summary::-webkit-details-marker { display: none; }
.primary-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 0.9rem;
}
.primary-nav a {
  color: var(--ink);
  text-decoration: none;
  font-size: 0.92rem;
  padding: 0.15rem 0;
  border-bottom: 2px solid transparent;
}
.primary-nav a:hover { border-bottom-color: var(--line); }
.primary-nav a[aria-current="page"] {
  border-bottom-color: var(--accent);
  font-weight: 600;
}
@media (min-width: 920px) {
  .nav-wrap > summary { display: none; }
  .nav-wrap { display: block; }
  .primary-nav { display: flex !important; }
}
@media (max-width: 919px) {
  .nav-wrap { margin-left: 0; width: 100%; }
  .nav-wrap:not([open]) .primary-nav { display: none; }
  .primary-nav { flex-direction: column; padding-top: 0.4rem; }
}
main { max-width: var(--max); margin: 0 auto; padding: 1.75rem 1rem 3.5rem; }
main.wide { max-width: var(--wide); }
.lede, .kicker { font-family: var(--sans); }
.kicker {
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 0.35rem;
}
h1 {
  font-size: 1.85rem;
  line-height: 1.2;
  font-weight: 650;
  letter-spacing: -0.02em;
  margin: 0 0 0.75rem;
}
h2 { font-size: 1.28rem; margin: 2rem 0 0.6rem; line-height: 1.25; }
h3 { font-size: 1.05rem; margin: 1.4rem 0 0.4rem; }
p { margin: 0 0 0.9rem; }
.lede { font-size: 1.02rem; color: var(--muted); margin-bottom: 1.25rem; }
.src, .hint, figcaption, caption {
  font-family: var(--sans);
  font-size: 0.82rem;
  color: var(--muted);
}
ul.plain, ul.notes { padding-left: 1.15rem; }
li { margin-bottom: 0.35rem; }
.callout {
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 0.85rem 1rem;
  margin: 1rem 0 1.25rem;
}
.callout.warn { background: var(--warn-bg); border-color: #e0c98a; color: var(--warn-ink); }
.callout.draft { background: var(--draft-bg); }
.callout.ok { background: var(--ok-bg); }
.jobs {
  display: grid;
  gap: 0.75rem;
  margin: 1.25rem 0 1.75rem;
}
@media (min-width: 640px) { .jobs { grid-template-columns: 1fr 1fr; } }
.job {
  display: block;
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 0.9rem 1rem;
  text-decoration: none;
  color: var(--ink);
}
.job:hover { border-color: var(--ink); }
.job strong { display: block; font-family: var(--sans); margin-bottom: 0.2rem; }
.job span { font-size: 0.92rem; color: var(--muted); }
.table-wrap { overflow-x: auto; margin: 1rem 0 1.4rem; }
table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--sans);
  font-size: 0.9rem;
  background: var(--paper);
}
th, td {
  text-align: left;
  padding: 0.45rem 0.6rem;
  border-bottom: 1px solid var(--line);
  vertical-align: top;
}
th { background: var(--bg-2); font-weight: 600; }
.mono { font-family: var(--mono); font-size: 0.86em; }
.filters {
  display: flex; flex-wrap: wrap; gap: 0.4rem; margin: 0.6rem 0 0.8rem;
  font-family: var(--sans);
}
.filters button {
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 0.25rem 0.65rem;
  cursor: pointer;
  font: inherit;
  font-size: 0.85rem;
}
.filters button[aria-pressed="true"] { background: var(--ink); color: var(--paper); }
.photo-needed {
  margin: 1rem 0 1.4rem;
}
.photo-needed-box {
  border: 1px dashed var(--muted);
  background: repeating-linear-gradient(-45deg, var(--bg-2), var(--bg-2) 8px, var(--bg) 8px, var(--bg) 16px);
  min-height: 11rem;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 1.2rem;
  font-family: var(--sans);
  font-size: 0.92rem;
  color: var(--muted);
}
figcaption { margin-top: 0.4rem; }
.finder {
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 1rem;
  margin: 1rem 0 1.5rem;
}
.finder-form fieldset {
  border: 0;
  margin: 0 0 0.85rem;
  padding: 0;
}
.finder-form legend { font-family: var(--sans); font-weight: 600; margin-bottom: 0.35rem; }
.choice { display: block; font-family: var(--sans); font-size: 0.95rem; margin: 0.2rem 0; }
.dim-row {
  display: grid;
  gap: 0.7rem;
}
@media (min-width: 640px) { .dim-row { grid-template-columns: 1fr 1fr 1fr; } }
.field label { display: block; font-family: var(--sans); font-size: 0.88rem; margin-bottom: 0.2rem; }
.field input, .field select {
  width: 100%;
  font: inherit;
  font-family: var(--sans);
  padding: 0.4rem 0.5rem;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
}
.flag-row { display: flex; flex-wrap: wrap; gap: 0.6rem 1.2rem; margin: 0.6rem 0; }
.extras { margin: 0.6rem 0 0.8rem; }
.extras.is-collapsed { display: none; }
.linkish {
  display: block;
  background: none; border: 0; color: var(--link); cursor: pointer;
  font-family: var(--sans); font-size: 0.9rem; padding: 0; text-decoration: underline;
  margin: 0.65rem 0 0.5rem;
}
.finder-form > .btn.primary {
  display: block;
  margin-top: 0.85rem;
  width: 100%;
  max-width: 16rem;
}
.btn {
  display: inline-block;
  font-family: var(--sans);
  font-size: 0.92rem;
  padding: 0.5rem 0.85rem;
  border: 1px solid var(--ink);
  background: var(--paper);
  color: var(--ink);
  text-decoration: none;
  cursor: pointer;
  line-height: 1.3;
}
.btn.primary { background: var(--ink); color: var(--paper); }
.btn.ghost { border-color: var(--line); }
.btn.merchant {
  background: var(--paper);
  border-color: var(--line);
  max-width: 22rem;
}
.btn.merchant:hover { border-color: var(--ink); }
.merchant-row {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
  margin: 0.5rem 0 0.7rem;
}
.size-out {
  font-family: var(--mono);
  font-size: 1.45rem;
  margin: 0 0 0.35rem;
  letter-spacing: -0.03em;
}
.finder-result { margin-top: 1rem; padding-top: 0.8rem; border-top: 1px solid var(--line); }
.finder-result:empty { display: none; }
.pill {
  display: inline-block;
  font-family: var(--sans);
  font-size: 0.8rem;
  padding: 0.15rem 0.5rem;
  border: 1px solid var(--line);
  margin: 0 0.35rem 0.35rem 0;
}
.pill.on { background: var(--ok-bg); }
.pill.off { color: var(--muted); }
.pill.opt { background: var(--warn-bg); }
.result-extra { margin-top: 0.8rem; }
.csv-status { margin-left: 0.6rem; }
.site-footer {
  border-top: 1px solid var(--line);
  background: var(--paper);
  font-family: var(--sans);
  font-size: 0.88rem;
  color: var(--muted);
  padding: 1.4rem 1rem 2.2rem;
}
.site-footer .inner { max-width: var(--wide); margin: 0 auto; }
.site-footer p { margin: 0 0 0.5rem; }
.disclosure { color: var(--ink); }
.tree {
  font-family: var(--sans);
  border-left: 3px solid var(--line);
  padding-left: 1rem;
  margin: 1rem 0;
}
.meta { font-family: var(--sans); font-size: 0.85rem; color: var(--muted); margin-bottom: 1rem; }
code { font-family: var(--mono); font-size: 0.88em; }
.toc { font-family: var(--sans); font-size: 0.92rem; }
hr { border: 0; border-top: 1px solid var(--line); margin: 2rem 0; }
@media print {
  .site-header, .site-footer .btn, .finder { break-inside: avoid; }
}