:root{
  --bg:#f6f7f4;
  --surface:#ffffff;
  --surface-2:#eef1ec;
  --text:#1b1f1d;
  --muted:#5b645f;
  --line:#dde2dc;
  --brand:#0f766e;
  --brand-strong:#0b5d57;
  --brand-soft:#d9f0ec;
  --accent:#e8a33d;
  --result-bg:#0f2f2c;
  --result-text:#f3faf8;
  --radius:14px;
  --shadow:0 1px 2px rgba(20,30,25,.05),0 6px 20px rgba(20,30,25,.06);
  --font:system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;
  --mono:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;
}
@media (prefers-color-scheme:dark){
  :root{
    --bg:#111513;
    --surface:#191e1c;
    --surface-2:#212826;
    --text:#e9eeeb;
    --muted:#9aa49f;
    --line:#2c3431;
    --brand:#3cc2b3;
    --brand-strong:#5fd6c8;
    --brand-soft:#173a36;
    --result-bg:#0d2724;
    --result-text:#f3faf8;
    --shadow:none;
  }
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--bg);color:var(--text);font:16px/1.6 var(--font)}
a{color:var(--brand)}
a:hover{color:var(--brand-strong)}
img,svg{max-width:100%}
.wrap{max-width:960px;margin:0 auto;padding:0 16px}

/* Header */
.site-header{background:var(--surface);border-bottom:1px solid var(--line);position:sticky;top:0;z-index:10}
.site-header .wrap{display:flex;align-items:center;justify-content:space-between;gap:16px;height:60px}
.logo{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--text);font-weight:800;font-size:1.15rem;letter-spacing:-.01em}
.logo-mark{width:32px;height:32px;border-radius:9px;background:var(--brand);color:#fff;display:grid;place-items:center;font-weight:900;font-size:1rem}
.logo b{color:var(--brand)}
.site-nav{display:flex;gap:4px;flex-wrap:wrap}
.site-nav a{text-decoration:none;color:var(--muted);font-size:.93rem;padding:6px 10px;border-radius:8px}
.site-nav a:hover{background:var(--surface-2);color:var(--text)}
@media (max-width:640px){.site-nav .hide-sm{display:none}}

/* Breadcrumb */
.crumbs{font-size:.85rem;color:var(--muted);margin:20px 0 4px}
.crumbs a{color:var(--muted);text-decoration:none}
.crumbs a:hover{text-decoration:underline}

/* Headings */
h1{font-size:clamp(1.6rem,4vw,2.2rem);line-height:1.2;letter-spacing:-.02em;margin:8px 0 8px}
h2{font-size:1.35rem;letter-spacing:-.01em;margin:36px 0 10px}
h3{font-size:1.08rem;margin:22px 0 6px}
.lead{color:var(--muted);font-size:1.05rem;margin:0 0 20px;max-width:65ch}

/* Calculator card */
.calc{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:20px;margin:16px 0}
.calc + .calc{margin-top:14px}
.calc h2{margin:0 0 14px;font-size:1.1rem}
.grid{display:grid;gap:14px;grid-template-columns:repeat(auto-fit,minmax(220px,1fr))}
.field label{display:block;font-size:.88rem;font-weight:600;margin:0 0 6px}
.field .hint{font-weight:400;color:var(--muted)}
input,select{width:100%;font:inherit;font-size:1.05rem;padding:11px 12px;border:1px solid var(--line);border-radius:10px;background:var(--bg);color:var(--text)}
input:focus,select:focus{outline:2px solid var(--brand);outline-offset:1px;border-color:transparent}
.inline-sentence{display:flex;flex-wrap:wrap;align-items:center;gap:8px;font-size:1.05rem}
.inline-sentence input{width:120px;flex:0 0 auto}
.check{display:flex;align-items:center;gap:8px;font-size:.95rem;margin-top:12px}
.check input{width:auto}
.tabs{display:flex;gap:6px;flex-wrap:wrap;margin:0 0 14px}
.tabs button{font:inherit;font-size:.92rem;border:1px solid var(--line);background:var(--bg);color:var(--text);padding:8px 12px;border-radius:999px;cursor:pointer}
.tabs button[aria-pressed="true"]{background:var(--brand);color:#fff;border-color:var(--brand)}

/* Result */
.result{margin-top:16px;background:var(--result-bg);color:var(--result-text);border-radius:12px;padding:16px 18px;min-height:56px}
.result .big{font-size:clamp(1.5rem,5vw,2rem);font-weight:800;letter-spacing:-.02em;line-height:1.2;font-variant-numeric:tabular-nums}
.result .sub{opacity:.85;font-size:.95rem;margin-top:4px}
.result.empty{opacity:.7}
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:10px;margin-top:12px}
.stat{background:rgba(255,255,255,.07);border-radius:10px;padding:10px 12px}
.stat .k{font-size:.8rem;opacity:.8}
.stat .v{font-size:1.15rem;font-weight:700;font-variant-numeric:tabular-nums}

/* Tables */
.table-wrap{overflow-x:auto;margin-top:14px;border:1px solid var(--line);border-radius:10px}
table{border-collapse:collapse;width:100%;font-size:.92rem;font-variant-numeric:tabular-nums}
th,td{padding:8px 10px;text-align:right;border-bottom:1px solid var(--line);white-space:nowrap}
th:first-child,td:first-child{text-align:left}
thead th{background:var(--surface-2);font-weight:600}
tbody tr:last-child td{border-bottom:0}
details{margin-top:14px}
summary{cursor:pointer;font-weight:600;color:var(--brand)}

/* Content */
.content{max-width:70ch}
.content p,.content li{color:var(--text)}
.formula{font-family:var(--mono);background:var(--surface-2);border-radius:10px;padding:12px 14px;overflow-x:auto;font-size:.95rem}
.note{background:var(--brand-soft);border-radius:10px;padding:12px 14px;font-size:.95rem}
.faq details{background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:12px 14px;margin:8px 0}
.faq summary{color:var(--text)}
.faq details p{margin:8px 0 0}

/* Home */
.hero{padding:36px 0 8px}
.hero h1{font-size:clamp(1.9rem,5vw,2.7rem)}
.quick{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:20px;margin:18px 0 8px}
.cards{display:grid;gap:14px;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));margin:16px 0}
.card{display:block;text-decoration:none;color:var(--text);background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:18px;box-shadow:var(--shadow);transition:border-color .15s,transform .15s}
.card:hover{border-color:var(--brand);transform:translateY(-2px);color:var(--text)}
.card .icon{width:40px;height:40px;border-radius:10px;background:var(--brand-soft);color:var(--brand);display:grid;place-items:center;font-weight:800;margin-bottom:10px}
.card h3{margin:0 0 4px}
.card p{margin:0;color:var(--muted);font-size:.93rem}

.related{display:flex;flex-wrap:wrap;gap:8px;margin:10px 0}
.related a{text-decoration:none;border:1px solid var(--line);background:var(--surface);padding:7px 12px;border-radius:999px;font-size:.92rem;color:var(--text)}
.related a:hover{border-color:var(--brand)}

/* Footer */
.site-footer{margin-top:56px;border-top:1px solid var(--line);background:var(--surface);padding:28px 0;font-size:.9rem;color:var(--muted)}
.site-footer .cols{display:flex;flex-wrap:wrap;gap:20px 40px;justify-content:space-between}
.site-footer a{color:var(--muted);text-decoration:none}
.site-footer a:hover{color:var(--text);text-decoration:underline}
.site-footer ul{list-style:none;padding:0;margin:6px 0 0}
.site-footer li{margin:4px 0}
.site-footer strong{color:var(--text)}
.legal{margin-top:20px;font-size:.82rem}

/* Ajustes para celulares */
.logo span:last-child,.site-nav a{white-space:nowrap}
.site-nav{flex-wrap:nowrap}
@media (max-width:480px){
  .logo{font-size:1.05rem;gap:8px}
  .logo-mark{width:30px;height:30px}
  .site-nav a{padding:6px 7px;font-size:.9rem}
  .calc,.quick{padding:16px}
  .inline-sentence{font-size:1rem;gap:6px}
  .inline-sentence input{width:92px;padding:10px}
  .tabs button{flex:1 1 auto}
  h2{margin-top:30px}
  .stats{grid-template-columns:repeat(2,minmax(0,1fr))}
  .stat .v{font-size:1.02rem}
}
@media (max-width:350px){ .site-nav a:nth-child(2){display:none} }

/* Frases con campos: cada número queda pegado a su texto */
.inline-sentence{row-gap:10px}
.inline-sentence .pair{display:inline-flex;align-items:center;gap:6px;white-space:nowrap;flex:0 0 auto}
.inline-sentence .pair input{width:104px;flex:0 0 auto;min-width:0}
.inline-sentence .pair select{width:auto;flex:0 0 auto;padding-right:6px}
@media (min-width:700px){.inline-sentence .pair input{width:130px}}

/* Categorías del inicio y pie */
h2.cat{font-size:1.15rem;margin:30px 0 4px;color:var(--muted);font-weight:700;text-transform:none}
h2.cat + .cards{margin-top:10px}
.site-footer ul.two-col{columns:2;column-gap:28px}
.site-footer ul.two-col li{break-inside:avoid}
/* Filas dinámicas (promedio de notas) */
.rows{display:grid;gap:8px}
.row{display:grid;grid-template-columns:1fr 1fr 40px;gap:8px;align-items:center}
.row.simple{grid-template-columns:1fr 40px}
.row-head{font-size:.82rem;font-weight:600;color:var(--muted)}
.icon-btn{font:inherit;width:40px;height:44px;border:1px solid var(--line);background:var(--bg);color:var(--muted);border-radius:10px;cursor:pointer;font-size:1.1rem}
.icon-btn:hover{color:var(--text);border-color:var(--text)}
.btn-add{font:inherit;margin-top:10px;border:1px dashed var(--line);background:transparent;color:var(--brand);padding:10px 14px;border-radius:10px;cursor:pointer;width:100%;font-weight:600}
.btn-add:hover{border-color:var(--brand)}
.steps{margin:10px 0 0;padding-left:18px;font-size:.93rem;opacity:.9}
.steps li{margin:2px 0}
.badge{display:inline-block;font-size:.75rem;font-weight:700;background:var(--brand-soft);color:var(--brand);padding:2px 8px;border-radius:999px;vertical-align:middle}
/* Tarjetas compactas en celular: ícono a la izquierda, menos scroll */
@media (max-width:640px){
  .cards{gap:10px}
  .card{display:grid;grid-template-columns:40px 1fr;column-gap:12px;align-items:start;padding:14px}
  .card .icon{grid-row:1 / span 2;margin:0}
  .card h3{font-size:1rem;margin:0}
  .card p{font-size:.88rem}
}
.site-footer ul.two-col li{margin:0 0 6px}
/* Computador: campos alineados aunque las etiquetas tengan distinto largo */
.grid{align-items:end}
input,select{height:50px;min-height:50px}
.combo{display:flex;gap:8px}.combo input{flex:1 1 auto;min-width:0}.combo select{flex:0 0 auto;width:auto}
select{padding-right:32px}
@media (prefers-color-scheme:dark){
  :root{--result-bg:#123f3a;--bg:#121614;--surface:#1a201e}
  input,select{background:#121614}
}