/* Fonts are self-hosted (SIL Open Font License) so nothing blocks the first paint. */
@font-face{font-family:"Barlow";font-style:normal;font-weight:400;font-display:swap;src:url(/fonts/barlow-400.woff2) format("woff2")}
@font-face{font-family:"Barlow";font-style:normal;font-weight:600;font-display:swap;src:url(/fonts/barlow-600.woff2) format("woff2")}
@font-face{font-family:"Barlow Condensed";font-style:normal;font-weight:600;font-display:swap;src:url(/fonts/barlow-condensed-600.woff2) format("woff2")}
@font-face{font-family:"Barlow Condensed";font-style:normal;font-weight:700;font-display:swap;src:url(/fonts/barlow-condensed-700.woff2) format("woff2")}
@font-face{font-family:"IBM Plex Mono";font-style:normal;font-weight:500;font-display:swap;src:url(/fonts/ibm-plex-mono-500.woff2) format("woff2")}
@font-face{font-family:"IBM Plex Mono";font-style:normal;font-weight:600;font-display:swap;src:url(/fonts/ibm-plex-mono-600.woff2) format("woff2")}

html{color-scheme:light}
body{margin:0}
img{max-width:100%}
[hidden]{display:none!important}

/* A field-tester kit: inputs left, a meter-style readout right, the explanation below. */
:root{
  --bg:#f3f4f1; --surface:#ffffff; --sunk:#e9ebe6; --fg:#1c2128; --muted:#5d6670; --line:#d3d7d0;
  --accent:#e2b007; --accent-ink:#1c2128; --accent-soft:#fbf1c7; --link:#1f5fbf;
  --readout:#1c2128; --readout-fg:#f6e7a6; --readout-muted:#a9a48a;
  --ok:#2f7d3c; --warn:#b5651d; --bad:#b4282d;
  --display:"Barlow Condensed","Arial Narrow",Arial,sans-serif;
  --body:"Barlow",system-ui,-apple-system,"Segoe UI",sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,"SFMono-Regular",Menlo,monospace;
}
@media (prefers-color-scheme: dark){:root:not([data-theme="light"]){
  --bg:#14171b; --surface:#1c2026; --sunk:#252a31; --fg:#e8eae6; --muted:#9aa2aa; --line:#323841;
  --accent:#f0c22b; --accent-ink:#14171b; --accent-soft:#3a3218; --link:#8db8ff;
  --readout:#0b0d10; --readout-fg:#f6e7a6; --readout-muted:#8f8a73;
  --ok:#5fbf6e; --warn:#e3964f; --bad:#ef6b6f; color-scheme:dark}}
:root[data-theme="dark"]{
  --bg:#14171b; --surface:#1c2026; --sunk:#252a31; --fg:#e8eae6; --muted:#9aa2aa; --line:#323841;
  --accent:#f0c22b; --accent-ink:#14171b; --accent-soft:#3a3218; --link:#8db8ff;
  --readout:#0b0d10; --readout-fg:#f6e7a6; --readout-muted:#8f8a73;
  --ok:#5fbf6e; --warn:#e3964f; --bad:#ef6b6f; color-scheme:dark}

*{box-sizing:border-box}
body{background:var(--bg);color:var(--fg);font-family:var(--body);font-size:16px;line-height:1.55;-webkit-text-size-adjust:100%}
a{color:var(--link)}
.wrap{max-width:1080px;margin:0 auto;padding-inline:16px;padding-block:16px 40px}
.skip{position:absolute;left:-9999px}.skip:focus{left:16px;top:8px;background:var(--accent);color:var(--accent-ink);padding:8px 12px;z-index:9}

header.site{display:flex;align-items:center;justify-content:space-between;gap:12px;padding-bottom:12px;border-bottom:3px solid var(--accent)}
.brand{display:flex;align-items:center;gap:12px;color:inherit;text-decoration:none;min-width:0}
.brand svg{flex:none}
.brand-name{display:block;font-family:var(--display);font-weight:700;font-size:1.75rem;letter-spacing:.02em;text-transform:uppercase;line-height:1}
.brand-tag{display:block;color:var(--muted);font-size:.9rem;margin-top:2px}
.theme{flex:none;background:transparent;border:1px solid var(--line);color:var(--fg);border-radius:6px;width:40px;height:40px;display:grid;place-items:center;cursor:pointer}
.std{font-family:var(--mono);font-size:.78rem;color:var(--muted);letter-spacing:.04em}

nav.tools{display:flex;gap:4px;overflow-x:auto;margin:14px 0 0;padding-bottom:2px;scrollbar-width:thin}
nav.tools a{flex:none;font:600 1rem/1 var(--display);letter-spacing:.05em;text-transform:uppercase;color:var(--muted);text-decoration:none;border:1px solid transparent;padding:12px 14px;border-radius:6px}
nav.tools a:hover{color:var(--fg);background:var(--sunk)}
nav.tools a[aria-current="page"]{background:var(--surface);color:var(--fg);border-color:var(--line);box-shadow:inset 0 3px 0 var(--accent)}
a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:2px solid var(--accent);outline-offset:2px}

.crumbs{display:flex;flex-wrap:wrap;gap:6px;font-size:.85rem;color:var(--muted);margin:14px 0 8px}
.crumbs a{color:var(--muted)}
main{margin-top:12px}
.crumbs + main{margin-top:0}

.panel{background:var(--surface);border:1px solid var(--line);border-radius:8px;padding:24px}
@media (max-width:520px){.panel{padding:16px}}
h1{font-family:var(--display);font-weight:700;font-size:2rem;line-height:1.1;text-transform:uppercase;letter-spacing:.02em;margin:0;text-wrap:balance}
.lede{color:var(--muted);margin:6px 0 20px;max-width:65ch;font-size:1.05rem}
.meta{color:var(--muted);font-size:.85rem;margin:-12px 0 20px}
.grid{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:24px;align-items:start}
@media (max-width:760px){.grid{grid-template-columns:minmax(0,1fr)}}
.fields{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px 16px}
.fields .full{grid-column:1/-1}
@media (max-width:420px){.fields{grid-template-columns:minmax(0,1fr)}}
label.f{display:flex;flex-direction:column;gap:5px;font-size:.82rem;font-weight:600;text-transform:uppercase;letter-spacing:.06em;color:var(--muted)}
.inrow{display:flex;gap:6px}
input,select{font:500 1rem var(--mono);color:var(--fg);background:var(--bg);border:1px solid var(--line);border-radius:6px;padding:10px;width:100%;min-width:0;font-variant-numeric:tabular-nums}
select{font-family:var(--body)}
.inrow select{width:auto;flex:none}
.hint{font-size:.8rem;text-transform:none;letter-spacing:0;font-weight:400;color:var(--muted)}
.sub{font-family:var(--mono);font-size:.75rem;color:var(--muted);letter-spacing:.08em;text-transform:uppercase;margin-top:6px}

.readout{background:var(--readout);color:var(--readout-fg);border-radius:8px;padding:20px;font-family:var(--mono)}
.readout .lbl{font-size:.72rem;letter-spacing:.12em;text-transform:uppercase;color:var(--readout-muted)}
.readout .big{font-size:2.6rem;font-weight:600;line-height:1.1;font-variant-numeric:tabular-nums;margin:4px 0 12px}
.readout .big small{font-size:1rem;color:var(--readout-muted);margin-left:6px}
.readout dl{display:grid;grid-template-columns:1fr auto;gap:6px 16px;margin:0;font-size:.9rem;font-variant-numeric:tabular-nums}
.readout dt{color:var(--readout-muted)}
.readout dd{margin:0;text-align:right}
.readout hr{border:0;border-top:1px dashed #4a4a40;margin:12px 0}
.readout .note{font-size:.85rem;color:var(--readout-muted);margin-top:10px;line-height:1.45}
.readout .copy{margin-top:14px;background:transparent;color:var(--readout-fg);border-color:#4a4a40}
.pill{display:inline-block;font:600 .75rem var(--mono);letter-spacing:.08em;text-transform:uppercase;padding:4px 10px;border-radius:99px;border:1px solid currentColor}
.pill.ok{color:#7fd88c}.pill.warn{color:#f0b070}.pill.bad{color:#ff8a8d}
.bar{display:flex;height:12px;border-radius:3px;overflow:hidden;background:#2c2f33;margin:4px 0 10px;position:relative}
.bar span{display:block;height:100%}
.legend{display:flex;flex-wrap:wrap;gap:4px 14px;font-size:.75rem;color:var(--readout-muted)}
.legend i{display:inline-block;width:10px;height:10px;border-radius:2px;margin-right:5px;vertical-align:-1px}

/* Explanations and guides */
.explain,.faq,.related{background:var(--surface);border:1px solid var(--line);border-radius:8px;padding:24px;margin-top:16px}
@media (max-width:520px){.explain,.faq,.related{padding:16px}}
.explain h2,.prose h2,.faq h2,.related h2{font-family:var(--display);font-size:1.45rem;text-transform:uppercase;letter-spacing:.03em;margin:28px 0 8px;line-height:1.15}
.explain h2:first-child,.faq h2,.related h2{margin-top:0}
.explain h3,.prose h3{font-family:var(--display);font-size:1.15rem;text-transform:uppercase;letter-spacing:.04em;margin:20px 0 6px}
.explain p,.prose p,.explain li,.prose li{max-width:70ch}
.explain p,.prose p{margin:0 0 12px}
.explain ul,.prose ul,.explain ol,.prose ol{padding-left:1.3em;margin:0 0 12px}
.explain li,.prose li{margin-bottom:4px}
code{font-family:var(--mono);font-size:.9em;background:var(--sunk);padding:1px 5px;border-radius:4px}
.formula{font-family:var(--mono);background:var(--sunk);border-left:3px solid var(--accent);padding:10px 14px;border-radius:4px;margin:0 0 14px;overflow-x:auto;white-space:nowrap}
.callout{border:1px solid var(--line);border-left:4px solid var(--warn);background:var(--bg);padding:12px 14px;border-radius:4px;margin:0 0 14px;max-width:70ch}
.callout p:last-child{margin-bottom:0}
.example{border:1px solid var(--line);background:var(--bg);padding:14px;border-radius:6px;margin:0 0 14px;max-width:70ch}
.example h3{margin-top:0}

/* Tables */
.tblwrap{overflow-x:auto;margin:4px 0 14px}
table{border-collapse:collapse;width:100%;font-variant-numeric:tabular-nums}
th,td{padding:7px 8px;border-bottom:1px solid var(--line);text-align:left;font-size:.92rem;vertical-align:middle}
th{font-size:.72rem;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);font-weight:600}
td input{padding:6px 8px;width:7.5em}
td.num,th.num{font-family:var(--mono);text-align:right}
caption{text-align:left;font-size:.85rem;color:var(--muted);padding-bottom:6px}
.flag{font:600 .72rem var(--mono);letter-spacing:.06em;text-transform:uppercase}
.flag.ok{color:var(--ok)}.flag.bad{color:var(--bad)}.flag.warn{color:var(--warn)}
.btn{font:600 .95rem var(--display);letter-spacing:.06em;text-transform:uppercase;padding:10px 14px;border-radius:6px;border:1px solid var(--line);background:var(--sunk);color:var(--fg);cursor:pointer}
.btn.primary{background:var(--accent);border-color:var(--accent);color:var(--accent-ink)}
.btn.ghost{background:transparent;border:none;color:var(--muted);padding:4px 8px;font-size:1.1rem}
.btnrow{display:flex;flex-wrap:wrap;gap:8px;margin-top:12px}

/* Color code */
.swatch{display:inline-block;width:22px;height:22px;border-radius:50%;border:2px solid var(--line);vertical-align:middle;position:relative;overflow:hidden;flex:none}
.swatch.striped::after{content:"";position:absolute;left:-2px;right:-2px;top:8px;height:4px;background:var(--stripe,#111);transform:rotate(-30deg)}
.cc-out{display:flex;flex-direction:column;gap:14px}
.cc-row{display:flex;align-items:center;gap:12px}
.cc-row .swatch{width:44px;height:44px;border-color:#3a3d42}
.cc-row .swatch.striped::after{top:17px;height:8px}
.cc-row .name{font-size:1.4rem;font-weight:600}
.chart12{display:grid;grid-template-columns:repeat(6,minmax(0,1fr));gap:8px;margin-top:6px}
@media (max-width:420px){.chart12{grid-template-columns:repeat(4,minmax(0,1fr))}}
.chart12 div{display:flex;flex-direction:column;align-items:center;gap:4px;padding:8px 2px;border-radius:6px;font-size:.78rem;border:1px solid transparent}
.chart12 div b{font:600 .75rem var(--mono);color:var(--muted)}
.chart12 div.on{border-color:var(--accent);background:var(--accent-soft)}
table.cc td .swatch{width:16px;height:16px;margin-right:6px;border-width:1px}
table.cc td .swatch.striped::after{top:6px;height:3px}
table.cc td{white-space:nowrap;font-size:.88rem;padding:5px 8px}

/* Home */
.cards{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:12px}
.cards a{display:flex;flex-direction:column;gap:4px;height:100%;padding:16px;border:1px solid var(--line);border-left:4px solid var(--c,var(--accent));border-radius:6px;background:var(--bg);color:inherit;text-decoration:none}
.cards a:hover{border-color:var(--c,var(--accent))}
.cards b{font-family:var(--display);font-size:1.2rem;text-transform:uppercase;letter-spacing:.03em}
.cards span{color:var(--muted);font-size:.92rem}

.faq details{border-top:1px solid var(--line);padding:12px 0}
.faq details:last-child{border-bottom:1px solid var(--line)}
.faq summary{cursor:pointer;font-weight:600;font-size:1.02rem}
.faq details > div{margin-top:8px;max-width:70ch}
.faq details > div p{margin:0 0 8px}
.related ul{list-style:none;padding:0;margin:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:10px}
.related a{display:flex;flex-direction:column;gap:2px;padding:12px;border:1px solid var(--line);border-radius:6px;color:inherit;text-decoration:none;height:100%}
.related a:hover{border-color:var(--accent)}
.related b{font-family:var(--display);text-transform:uppercase;letter-spacing:.03em}
.related span{font-size:.88rem;color:var(--muted)}

/* Ads: space is reserved before the ad loads so nothing jumps under a thumb. */
.ad{margin:32px auto 0;text-align:center;min-height:300px;max-width:100%}
.ad-label{font:500 .68rem var(--mono);letter-spacing:.12em;text-transform:uppercase;color:var(--muted);margin-bottom:4px}

footer.site{margin-top:32px;border-top:1px solid var(--line);padding-top:20px;color:var(--muted);font-size:.9rem}
footer .cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:16px}
footer h2{font:600 .8rem var(--mono);letter-spacing:.1em;text-transform:uppercase;margin:0 0 8px;color:var(--fg)}
footer ul{list-style:none;padding:0;margin:0}
footer li{margin-bottom:6px}
footer a{color:var(--muted)}
footer .fine{margin-top:18px;max-width:75ch;font-size:.82rem}

@media (prefers-reduced-motion:no-preference){.bar span{transition:width .25s ease}}
@media print{
  nav.tools,.theme,.ad,footer.site,.related,.btnrow,.copy,.crumbs{display:none!important}
  body{background:#fff;color:#000}
  .panel,.explain,.faq{border:0;padding:0}
  .readout{background:#fff;color:#000;border:1px solid #000}
}

/* Count charts (144, 288): one row per tube, prints on a page */
table.grid-chart th,table.grid-chart td{padding:4px 6px;font-size:.82rem;border:1px solid var(--line)}
table.grid-chart thead th{text-align:center;text-transform:none;letter-spacing:0;font-family:var(--mono)}
table.grid-chart th[scope=row]{white-space:nowrap;font-weight:600;text-transform:none;letter-spacing:0;font-size:.82rem;color:var(--fg)}
table.grid-chart td{text-align:center}
table.grid-chart tbody tr:nth-child(even){background:var(--bg)}
@media print{table.grid-chart th,table.grid-chart td{font-size:9pt;padding:2px 4px}.swatch{print-color-adjust:exact;-webkit-print-color-adjust:exact}}
td input.name-in{width:11em;font-family:var(--body)}
td input.qty-in{width:4.5em}
@media (max-width:520px){
  td input{width:4.2em;padding:6px 4px}
  td input.name-in{width:7em}
  td input.qty-in{width:3.2em}
  th,td{padding:6px 3px}
}
.prose ul.cards{padding:0;margin-bottom:8px}.prose .cards li{max-width:none;margin:0}

/* Chart images */
.chart-img{margin:8px 0 18px;max-width:900px}
.chart-img img{display:block;width:100%;height:auto;border:1px solid var(--line);border-radius:6px;background:#fff}
.chart-img figcaption{font-size:.88rem;color:var(--muted);margin-top:6px}