html{-webkit-text-size-adjust:100%}body{margin:0}img{max-width:100%}[hidden]{display:none!important}

/* Layout: cabecera tipo letrero de obra + pestañas (selector en móvil); cada calculadora en dos columnas (datos | resultados) con guía corta debajo */
:root{
  --bg:#eceeef; --panel:#ffffff; --ink:#1d2730; --muted:#5c6973; --line:#cfd5d9;
  --accent:#e3a008; --accent-ink:#1d2730; --sign:#1d2730; --sign-ink:#f4f6f7; --field:#f6f7f8;
  --ok:#2f7d4f; --warn:#b4541a;
  --display:"Barlow Condensed","Arial Narrow",Arial,sans-serif;
  --body:"IBM Plex Sans",system-ui,-apple-system,"Segoe UI",sans-serif;
  --mono:"IBM Plex Mono",ui-monospace,Menlo,Consolas,monospace;
}
@media (prefers-color-scheme:dark){:root:not([data-theme="light"]){
  --bg:#151b20; --panel:#1d252c; --ink:#e6eaed; --muted:#98a4ad; --line:#2f3a43;
  --accent:#f0b429; --accent-ink:#151b20; --sign:#0f1418; --sign-ink:#e6eaed; --field:#232c34;
  --ok:#5cc28a; --warn:#f08a4b; color-scheme:dark}}
:root[data-theme="dark"]{
  --bg:#151b20; --panel:#1d252c; --ink:#e6eaed; --muted:#98a4ad; --line:#2f3a43;
  --accent:#f0b429; --accent-ink:#151b20; --sign:#0f1418; --sign-ink:#e6eaed; --field:#232c34;
  --ok:#5cc28a; --warn:#f08a4b; color-scheme:dark}
*{box-sizing:border-box}
body{background:var(--bg);color:var(--ink);font-family:var(--body);font-size:15px;line-height:1.5}
.wrap{max-width:1000px;margin:0 auto;padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px))}
header{background:var(--sign);color:var(--sign-ink);border-bottom:6px solid var(--accent)}
header .wrap{padding-block:28px 22px;display:flex;flex-direction:column;gap:6px}
.tag{font-family:var(--mono);font-size:12px;letter-spacing:.08em;text-transform:uppercase;color:var(--accent)}
h1{font-family:var(--display);font-weight:700;font-size:clamp(34px,6vw,52px);line-height:1;margin:0;letter-spacing:.01em;text-transform:uppercase;text-wrap:balance}
header p{margin:0;max-width:62ch;color:var(--sign-ink);opacity:.8}
a:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid var(--accent);outline-offset:2px}
main .wrap{padding-block:0 48px}
section.calc{background:var(--panel);border:1px solid var(--line);border-radius:6px;display:grid;grid-template-columns:1fr 1fr;overflow:hidden}
@media (max-width:720px){section.calc{grid-template-columns:1fr}}
.inputs,.results{padding:24px;display:flex;flex-direction:column;gap:16px;min-width:0}
.results{background:var(--field);border-left:1px solid var(--line)}
@media (max-width:720px){.results{border-left:0;border-top:1px solid var(--line)}}
.guide{grid-column:1/-1;border-top:1px solid var(--line);padding:20px 24px;display:flex;flex-direction:column;gap:8px}
.guide h3{color:var(--ink)}
.guide p{margin:0;max-width:72ch;color:var(--muted)}
h2{font-family:var(--display);font-weight:700;font-size:26px;text-transform:uppercase;margin:0;letter-spacing:.02em}
h3{font-family:var(--mono);font-size:12px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);margin:0;font-weight:500}
.row{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.row3{display:grid;grid-template-columns:repeat(3,1fr);gap:12px}
@media (max-width:420px){.row3{grid-template-columns:1fr 1fr}}
label{display:flex;flex-direction:column;gap:4px;font-size:13px;font-weight:500;color:var(--muted)}
label.check{flex-direction:row;align-items:center;gap:8px;color:var(--ink);font-size:14px}
label.check input{width:18px;height:18px;padding:0}
input,select{font:500 16px var(--mono);color:var(--ink);background:var(--field);border:1px solid var(--line);border-radius:4px;padding:9px 10px;width:100%;min-width:0}
.results input,.results select{background:var(--panel)}
.big{display:flex;flex-direction:column;gap:2px;padding-bottom:14px;border-bottom:2px solid var(--ink)}
.big .num{font-family:var(--display);font-weight:700;font-size:56px;line-height:1;font-variant-numeric:tabular-nums;overflow-wrap:anywhere}
.big .unit{font-size:14px;color:var(--muted)}
dl{margin:0;display:grid;grid-template-columns:1fr auto;gap:8px 16px}
dt{color:var(--muted)}
dd{margin:0;font-family:var(--mono);text-align:right;font-variant-numeric:tabular-nums}
.note{font-size:13px;color:var(--muted);margin:0}
.pill{display:inline-block;font:500 12px var(--mono);letter-spacing:.06em;text-transform:uppercase;padding:2px 8px;border-radius:99px;border:1px solid currentColor}
.pill.ok{color:var(--ok)} .pill.warn{color:var(--warn)}
.checks{display:grid;grid-template-columns:1fr 1fr;gap:8px}
.prices{display:grid;grid-template-columns:1fr 1fr;gap:10px}
.table-wrap{overflow-x:auto}
table{width:100%;border-collapse:collapse;font-size:14px}
th,td{padding:7px 6px;border-bottom:1px solid var(--line);text-align:right;font-variant-numeric:tabular-nums;white-space:nowrap}
th:first-child,td:first-child{text-align:left;white-space:normal}
th{font:500 11px var(--mono);letter-spacing:.06em;text-transform:uppercase;color:var(--muted)}
td{font-family:var(--mono)}
td:first-child{font-family:var(--body)}
.empty{color:var(--muted);font-size:14px;margin:0}
footer .wrap{padding-block:0 32px}
footer p{font-size:13px;color:var(--muted);max-width:70ch;margin:0}

/* Sitio */
.topbar{display:flex;justify-content:space-between;align-items:center;gap:12px;flex-wrap:wrap}
.brand{display:inline-flex;align-items:center;gap:10px;font-family:var(--display);font-weight:700;font-size:22px;text-transform:uppercase;letter-spacing:.03em;color:var(--sign-ink);text-decoration:none}
.brand b{color:var(--accent);font-weight:700}
.toplinks{display:flex;gap:16px;flex-wrap:wrap}
.toplinks a{color:var(--sign-ink);opacity:.85;text-decoration:none;font-size:14px}
.toplinks a:hover{opacity:1;text-decoration:underline}
header .hero{display:flex;flex-direction:column;gap:6px;margin-top:18px}
.crumbs{font-size:13px;color:var(--muted);padding-block:14px 10px;margin:0}
.crumbs a{color:var(--muted)}
.tools{display:flex;flex-direction:column;gap:18px;margin-top:28px}
.tools h2{font-size:22px}
.chips{display:flex;flex-wrap:wrap;gap:6px}
.chips a{font-family:var(--display);font-weight:600;font-size:16px;text-transform:uppercase;letter-spacing:.04em;text-decoration:none;color:var(--ink);background:var(--panel);border:1px solid var(--line);padding:5px 12px;border-radius:4px}
.chips a:hover,.chips a[aria-current="page"]{background:var(--accent);color:var(--accent-ink);border-color:var(--accent)}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:12px}
.card{display:flex;flex-direction:column;gap:6px;background:var(--panel);border:1px solid var(--line);border-radius:6px;padding:18px;text-decoration:none;color:var(--ink);min-width:0}
.card:hover{border-color:var(--accent)}
.card strong{font-family:var(--display);font-size:22px;text-transform:uppercase;letter-spacing:.02em;line-height:1.1}
.card span{color:var(--muted);font-size:14px}
.cat{font-family:var(--mono);font-size:12px;letter-spacing:.08em;text-transform:uppercase;color:var(--muted);margin:8px 0 0}
.prose{background:var(--panel);border:1px solid var(--line);border-radius:6px;padding:24px;display:flex;flex-direction:column;gap:14px;max-width:760px}
.prose h2{font-size:22px}
.prose p,.prose li{margin:0;color:var(--ink);max-width:70ch}
.prose ul{margin:0;padding-left:20px;display:flex;flex-direction:column;gap:6px}
.prose a,.guide a,label.check a{color:var(--ink)}
.site-footer{border-top:1px solid var(--line);margin-top:8px}
.site-footer .wrap{padding-block:20px 32px;display:flex;flex-direction:column;gap:10px}
.site-footer nav{display:flex;gap:16px;flex-wrap:wrap}
.site-footer nav a{color:var(--muted);font-size:13px}
.article{margin-top:20px;max-width:none}
.article p,.article li{max-width:72ch}
.article ol{margin:0;padding-left:22px;display:flex;flex-direction:column;gap:6px}
.answer{background:var(--field);border:1px solid var(--line);border-radius:6px;padding:14px 16px;display:flex;flex-direction:column;gap:4px}
.answer-label{font:500 11px var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
.formula{font-family:var(--mono);background:var(--field);border:1px solid var(--line);border-radius:4px;padding:10px 12px;overflow-x:auto}
.faq{display:flex;flex-direction:column;gap:8px}
.faq details{border:1px solid var(--line);border-radius:6px;padding:10px 14px;background:var(--panel)}
.faq summary{cursor:pointer;font-weight:600}
.faq details p{margin-top:8px;color:var(--muted)}
.byline{font-size:13px;color:var(--muted)}
.prose .table-wrap{margin:0}
.prose th,.prose td{white-space:normal}
.prose td:first-child{min-width:7ch}
.toc{margin:0;padding-left:22px;columns:2;column-gap:32px}
@media (max-width:560px){.toc{columns:1}}
.step{display:flex;flex-direction:column;gap:12px;padding-top:12px;border-top:1px solid var(--line)}
.step-n{display:inline-flex;align-items:center;justify-content:center;min-width:1.6em;height:1.6em;border-radius:4px;background:var(--accent);color:var(--accent-ink);font-size:.85em;margin-right:6px}
.calc-links{font-size:14px;color:var(--muted)}
.normativa ul{list-style:none;padding:0;margin:0;display:flex;flex-direction:column;gap:8px}
.normativa li span{color:var(--muted)}
.letters{display:flex;flex-wrap:wrap;gap:4px}
.letters a{font-family:var(--display);font-weight:700;font-size:18px;min-width:34px;text-align:center;padding:4px 6px;border:1px solid var(--line);border-radius:4px;background:var(--panel);color:var(--ink);text-decoration:none}
.terms{margin:0;display:flex;flex-direction:column;gap:0}
.term{padding:14px 0;border-top:1px solid var(--line);display:flex;flex-direction:column;gap:6px;scroll-margin-top:16px}
.term dt{color:var(--ink);font-family:var(--display);font-weight:700;font-size:22px;text-transform:uppercase;letter-spacing:.02em}
.term dd{margin:0;font-family:var(--body);text-align:left;font-variant-numeric:normal;display:flex;flex-direction:column;gap:6px;max-width:72ch}
.tags{display:flex;flex-wrap:wrap;gap:6px;align-items:center;font-size:13px;color:var(--muted)}
.tag-n{font:500 12px var(--mono);border:1px solid var(--line);border-radius:99px;padding:2px 8px;color:var(--ink);text-decoration:none;background:var(--field)}
.norm{scroll-margin-top:16px}
.norm td:first-child{font-family:var(--mono);white-space:nowrap}
.norm td{vertical-align:top;white-space:normal;text-align:left;font-family:var(--body);font-size:14px}
.norm td:first-child{font-family:var(--mono)}
main .wrap{padding-block:0 40px}