/* Layout: calculator on the left, a spec-plate readout on the right; article and related tools below.
   Palette: cool shop-floor greys, ink in deep slate-green, one hi-vis orange accent. */
:root {
  --paper: #eef1ef;
  --panel: #ffffff;
  --ink: #18211e;
  --muted: #56635e;
  --rule: #cfd6d2;
  --accent: #c4410b;
  --accent-ink: #ffffff;
  --plate: #1f2a26;
  --plate-ink: #e9efe9;
  --plate-muted: #9fb0a8;
  --ok: #2f7d3a;
  --warn: #a86a00;
  --bad: #b42323;
  --display: "Barlow Condensed", "Arial Narrow", "Roboto Condensed", sans-serif;
  --body: "IBM Plex Sans", "Segoe UI", system-ui, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  --r: 6px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --paper: #111614; --panel: #19201d; --ink: #e3e9e5; --muted: #98a59f; --rule: #2d3833;
    --accent: #ff7a3d; --accent-ink: #1a0d05; --plate: #0b0f0d; --plate-ink: #e9efe9; --plate-muted: #8fa198;
    --ok: #6cc47a; --warn: #e3a93b; --bad: #ff7b7b; color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --paper: #111614; --panel: #19201d; --ink: #e3e9e5; --muted: #98a59f; --rule: #2d3833;
  --accent: #ff7a3d; --accent-ink: #1a0d05; --plate: #0b0f0d; --plate-ink: #e9efe9; --plate-muted: #8fa198;
  --ok: #6cc47a; --warn: #e3a93b; --bad: #ff7b7b; color-scheme: dark;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--paper); color: var(--ink); font: 16px/1.6 var(--body); }
a { color: var(--accent); text-underline-offset: 2px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
[hidden] { display: none !important; }

.wrap { max-width: 1120px; margin: 0 auto; padding-left: max(16px, env(safe-area-inset-left, 0px)); padding-right: max(16px, env(safe-area-inset-right, 0px)); }

/* header */
.site-head { border-bottom: 1px solid var(--rule); background: var(--panel); }
.site-head .wrap { display: flex; align-items: center; justify-content: space-between; gap: 16px; padding-block: 12px; flex-wrap: wrap; }
.brand { font: 700 1.6rem/1 var(--display); letter-spacing: 0.04em; text-transform: uppercase; color: var(--ink); text-decoration: none; display: flex; align-items: baseline; gap: 10px; }
.brand b { color: var(--accent); font-weight: 700; }
.brand small { font: 500 0.78rem/1 var(--body); letter-spacing: 0.02em; text-transform: none; color: var(--muted); }
.site-nav { display: flex; gap: 18px; flex-wrap: wrap; font-size: 0.92rem; }
.site-nav a { color: var(--muted); text-decoration: none; }
.site-nav a:hover { color: var(--ink); }

/* page heading */
.crumbs { font-size: 0.85rem; color: var(--muted); padding-top: 22px; }
.crumbs a { color: var(--muted); }
h1, h2, h3 { font-family: var(--display); line-height: 1.1; text-wrap: balance; margin: 0; }
h1 { font-size: clamp(2rem, 4.5vw, 2.9rem); font-weight: 700; letter-spacing: 0.005em; margin-top: 6px; }
.lede { color: var(--muted); max-width: 64ch; margin: 8px 0 22px; font-size: 1.05rem; }

/* calculator */
.calc { display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(0, 1fr); gap: 20px; align-items: start; }
.inputs { background: var(--panel); border: 1px solid var(--rule); border-radius: var(--r); padding: 20px; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px 16px; }
.field { display: flex; flex-direction: column; gap: 5px; min-width: 0; }
.field.full { grid-column: 1 / -1; }
.lbl { font-size: 0.8rem; font-weight: 600; letter-spacing: 0.04em; text-transform: uppercase; color: var(--muted); }
.ctl { display: flex; align-items: stretch; border: 1px solid var(--rule); border-radius: 4px; background: var(--paper); }
.ctl:focus-within { border-color: var(--accent); }
.ctl input, .ctl select { flex: 1; min-width: 0; border: 0; background: transparent; color: var(--ink); font: 500 1rem/1.2 var(--mono); padding: 10px 10px; font-variant-numeric: tabular-nums; }
.ctl select { font-family: var(--body); cursor: pointer; }
.ctl input:focus, .ctl select:focus { outline: none; }
.u { display: flex; align-items: center; padding: 0 10px; font: 0.82rem var(--mono); color: var(--muted); border-left: 1px solid var(--rule); white-space: nowrap; }
.hint { font-size: 0.78rem; color: var(--muted); line-height: 1.35; }
.field.check { flex-direction: row; align-items: center; gap: 10px; font-size: 0.95rem; padding-top: 20px; cursor: pointer; }
.field.check input { width: 18px; height: 18px; accent-color: var(--accent); }

/* readout: a stamped equipment nameplate */
.readout { background: var(--plate); color: var(--plate-ink); border-radius: var(--r); padding: 18px 20px 16px; position: sticky; top: 16px; }
.readout-h { font: 600 0.8rem/1 var(--body); letter-spacing: 0.14em; text-transform: uppercase; color: var(--plate-muted); display: flex; justify-content: space-between; padding-bottom: 12px; border-bottom: 1px dashed color-mix(in srgb, var(--plate-muted) 45%, transparent); }
.rows { margin: 0; }
.row { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 4px 12px; padding: 10px 0; border-bottom: 1px solid color-mix(in srgb, var(--plate-muted) 20%, transparent); align-items: baseline; }
.row dt { font-size: 0.86rem; color: var(--plate-muted); }
.row dd { margin: 0; text-align: right; font-family: var(--mono); font-variant-numeric: tabular-nums; display: flex; flex-wrap: wrap; justify-content: flex-end; align-items: baseline; gap: 2px 6px; }
.val { font-size: 1.05rem; font-weight: 600; }
.unit { font-size: 0.8rem; color: var(--plate-muted); }
.tag { flex-basis: 100%; font: 0.75rem var(--body); color: var(--plate-muted); }
.row.big { grid-template-columns: 1fr; padding: 14px 0 12px; }
.row.big dd { justify-content: flex-start; text-align: left; }
.row.big .val { font-size: 2.4rem; line-height: 1; color: var(--plate-ink); }
.row.big .tag { flex-basis: auto; }
.row.big dt { text-transform: uppercase; letter-spacing: 0.08em; font-size: 0.75rem; }
.row.s-ok .val { color: #7fd38b; } .row.s-warn .val { color: #f2b84b; } .row.s-bad .val { color: #ff8a80; }
.row.s-ok .tag::before, .row.s-warn .tag::before, .row.s-bad .tag::before { content: "●"; margin-right: 5px; }
.row.s-ok .tag::before { color: #7fd38b; } .row.s-warn .tag::before { color: #f2b84b; } .row.s-bad .tag::before { color: #ff8a80; }
.note { font-size: 0.8rem; color: var(--plate-muted); margin: 12px 0 0; line-height: 1.45; }
.err { color: #ffb4a8; margin: 16px 0; }
.copy-link { margin-top: 14px; background: transparent; color: var(--plate-ink); border: 1px solid color-mix(in srgb, var(--plate-muted) 50%, transparent); border-radius: 4px; padding: 8px 12px; font: 500 0.82rem var(--body); cursor: pointer; max-width: 100%; overflow-wrap: anywhere; }
.copy-link:hover { border-color: var(--plate-ink); }

/* ads */
.ad { margin: 26px 0; min-height: 90px; display: flex; justify-content: center; }
.ad-side { min-height: 250px; }

/* article */
.content { display: grid; grid-template-columns: minmax(0, 1fr) 300px; gap: 40px; margin-top: 36px; }
.prose { max-width: 68ch; min-width: 0; }
.prose h2 { font-size: 1.7rem; font-weight: 700; margin: 34px 0 10px; }
.prose h2:first-child { margin-top: 0; }
.prose h3 { font-size: 1.25rem; font-weight: 600; margin: 22px 0 6px; }
.prose p, .prose li { color: var(--ink); }
.prose ul, .prose ol { padding-left: 1.3em; }
.formula { font: 0.95rem/1.7 var(--mono); background: var(--panel); border: 1px solid var(--rule); border-left: 3px solid var(--accent); padding: 12px 16px; overflow-x: auto; white-space: pre; border-radius: 0 4px 4px 0; }
.table-wrap { overflow-x: auto; }
.prose table { border-collapse: collapse; font-size: 0.9rem; min-width: 100%; }
.prose th, .prose td { text-align: left; padding: 7px 10px; border-bottom: 1px solid var(--rule); font-variant-numeric: tabular-nums; }
.prose th { font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--muted); }
.faq dt { font-weight: 600; margin-top: 16px; }
.faq dd { margin: 4px 0 0; color: var(--ink); }
.side { display: flex; flex-direction: column; gap: 22px; min-width: 0; }
.side h3 { font-size: 1.1rem; text-transform: uppercase; letter-spacing: 0.06em; font-weight: 600; color: var(--muted); margin-bottom: 8px; }
.side ul { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--rule); }
.side li { border-bottom: 1px solid var(--rule); }
.side li a { display: block; padding: 9px 0; color: var(--ink); text-decoration: none; }
.side li a:hover { color: var(--accent); }
.disclaimer { font-size: 0.85rem; color: var(--muted); border-top: 1px solid var(--rule); padding-top: 14px; margin-top: 30px; }

/* home */
.hero { padding-block: 36px 10px; }
.hero h1 { font-size: clamp(2.3rem, 6vw, 3.6rem); max-width: 18ch; }
.hero p { color: var(--muted); max-width: 60ch; font-size: 1.08rem; }
.cat { margin-top: 34px; }
.cat h2 { font-size: 1rem; letter-spacing: 0.14em; text-transform: uppercase; color: var(--muted); font-weight: 600; padding-bottom: 8px; border-bottom: 2px solid var(--ink); }
.tools { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 0 28px; }
.tool { display: block; padding: 14px 0; border-bottom: 1px solid var(--rule); text-decoration: none; color: var(--ink); }
.tool strong { font: 600 1.25rem/1.2 var(--display); display: block; }
.tool span { font-size: 0.9rem; color: var(--muted); }
.tool:hover strong { color: var(--accent); }

.site-foot { margin-top: 56px; border-top: 1px solid var(--rule); background: var(--panel); font-size: 0.88rem; color: var(--muted); }
.site-foot .wrap { padding-block: 22px; display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px; }
.site-foot a { color: var(--muted); margin-right: 16px; }

@media (max-width: 860px) {
  .calc, .content { grid-template-columns: minmax(0, 1fr); }
  .readout { position: static; }
  .content { gap: 10px; }
}
@media (max-width: 480px) {
  .inputs { grid-template-columns: minmax(0, 1fr); padding: 16px; }
  .field.check { padding-top: 0; }
  .row.big .val { font-size: 2rem; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; animation: none !important; } }

/* question pages */
.answer { display: flex; flex-wrap: wrap; align-items: baseline; gap: 6px 14px; margin: 10px 0 22px; padding: 14px 18px; background: var(--panel); border: 1px solid var(--rule); border-left: 4px solid var(--accent); border-radius: 0 var(--r) var(--r) 0; }
.answer-val { font: 600 clamp(1.3rem, 3.2vw, 1.75rem)/1.2 var(--mono); font-variant-numeric: tabular-nums; }
.answer-note { color: var(--muted); font-size: 0.9rem; }
.quick { columns: 2 260px; column-gap: 28px; padding-left: 0; list-style: none; font-size: 0.92rem; }
.quick li { break-inside: avoid; padding: 3px 0; }
.vd-grid td { white-space: nowrap; }
.vd-grid .over { color: var(--bad); font-weight: 600; }

/* pins and chart pack */
.pin-card img { width: 100%; height: auto; border-radius: 4px; border: 1px solid var(--rule); display: block }
.pin-card .hint { font-size: 0.82rem; color: var(--muted); margin: 6px 0 0 }
.pack-link { margin: 8px 0 0; font-weight: 600 }
.buy { display: inline-block; background: var(--accent); color: var(--accent-ink); text-decoration: none; font: 600 1.05rem var(--body); padding: 12px 22px; border-radius: 4px }
.buy:hover { filter: brightness(1.08) }
.previews { gap: 14px }
.previews img { width: 100%; height: auto; border: 1px solid var(--rule); border-radius: 4px; box-shadow: 0 2px 8px rgba(0,0,0,.08) }