/* Reset base */
:root{color-scheme:light;box-sizing:border-box;padding-top:env(safe-area-inset-top,0px);padding-bottom:env(safe-area-inset-bottom,0px)}html{scroll-padding-top:env(safe-area-inset-top,0px)}body{margin:0;padding:0;font:14px -apple-system,BlinkMacSystemFont,sans-serif;background:#fff;color:#000}img{max-width:100%}[hidden]:not([hidden=until-found i]){display:none!important}

/* Layout: estilo Björk — cabecera en columna fija a la izquierda (escritorio), columna de lectura de 720px, publicidad lateral a la derecha solo en pantallas anchas. */
:root{
  --bg:#ffffff;
  --fg:#111111;
  --primary:#5857ff;
  --secondary:#6b6a6a;
  --tertiary:#e2e2e2;
  --quaternary:#f3f2f2;
  --ok:#16794a;
  --bad:#c42f2f;
  --font:"Albert Sans", ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
  --font-math:"STIX Two Text", "Cambria Math", Georgia, serif;
  --fs-small:clamp(15px, 0.9rem + .2vw, 17px);
  --fs-body:clamp(17px, 1rem + .3vw, 20px);
  --fs-h3:clamp(21px, 1.2rem + .6vw, 26px);
  --fs-h2:clamp(26px, 1.3rem + 1.4vw, 38px);
  --fs-h1:clamp(38px, 1.6rem + 3.4vw, 64px);
  --content:720px;
  --gutter:clamp(16px, 5vw, 64px);
}
:root, :root[data-theme="dark"]{color-scheme:light}

*{box-sizing:border-box}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion: reduce){ html{scroll-behavior:auto} }
body{background:var(--bg);color:var(--fg);font-family:var(--font);font-size:var(--fs-body);font-weight:450;line-height:1.55;letter-spacing:-.01em;-webkit-font-smoothing:antialiased}
body::before{content:"";position:fixed;inset:0 0 auto;height:env(safe-area-inset-top,0px);z-index:10;background:var(--bg)}
a{color:inherit;text-decoration:underline;text-decoration-thickness:1px;text-underline-offset:.18em}
a:hover{text-decoration:none}
:focus-visible{outline:2px solid var(--primary);outline-offset:3px;border-radius:4px}
.math{font-family:var(--font-math);font-style:italic;font-weight:500;white-space:nowrap;letter-spacing:0}
.math .up{font-style:normal}
sup{line-height:0}

/* ---------- Cabecera ---------- */
.site{padding:20px max(var(--gutter), env(safe-area-inset-left,0px)) 20px max(var(--gutter), env(safe-area-inset-right,0px));display:flex;flex-wrap:wrap;align-items:center;gap:12px 28px;border-bottom:1px solid var(--tertiary)}
.logo{font-weight:600;font-size:22px;letter-spacing:-.02em;text-decoration:none;margin-right:auto}
.nav{display:flex;flex-wrap:wrap;gap:4px 20px;list-style:none;margin:0;padding:0}
.nav a{text-decoration:none}
.nav a:hover{text-decoration:underline}
.ccaa{display:grid;gap:4px;font-size:14px;color:var(--secondary)}
.ccaa select{font:inherit;font-size:15px;color:var(--fg);background:var(--bg);border:1px solid var(--tertiary);border-radius:999px;padding:6px 12px;max-width:230px}
@media (min-width:1280px){
  .site{position:fixed;top:0;bottom:0;left:0;width:240px;flex-direction:column;align-items:flex-start;justify-content:space-between;border:0;padding:56px 0 48px max(48px, env(safe-area-inset-left,0px))}
  .logo{margin:0}
  .nav{flex-direction:column;gap:6px;font-size:var(--fs-body)}
}

/* ---------- Rejilla ---------- */
.page{display:grid;grid-template-columns:minmax(0,var(--content));justify-content:center;gap:64px;padding:48px max(var(--gutter), env(safe-area-inset-right,0px)) 120px max(var(--gutter), env(safe-area-inset-left,0px))}
@media (min-width:1280px){ .page{margin-left:240px;padding-top:72px} }
@media (min-width:1500px){ .page{grid-template-columns:minmax(0,var(--content)) 300px} }
.aside{display:none}
@media (min-width:1500px){ .aside{display:block;position:sticky;top:48px;align-self:start} }
main{min-width:0}
main > * + *{margin-top:1.1em}

.crumbs{display:flex;flex-wrap:wrap;gap:6px;list-style:none;padding:0;margin:0;font-size:var(--fs-small);color:var(--secondary)}
.crumbs li+li::before{content:"/";margin-right:6px;color:var(--tertiary)}
.crumbs a{text-decoration:none}
.crumbs a:hover{text-decoration:underline}
h1,h2,h3{font-weight:600;letter-spacing:-.02em;text-wrap:balance}
h1{font-size:var(--fs-h1);line-height:1.05;letter-spacing:-.03em;margin:.35em 0 0}
h2{font-size:var(--fs-h2);line-height:1.15;margin:2.4em 0 .6em;scroll-margin-top:32px}
h3{font-size:var(--fs-h3);line-height:1.2;margin:1.8em 0 .4em;scroll-margin-top:32px}
p,li{max-width:66ch}
.meta{font-size:var(--fs-small);color:var(--secondary);display:flex;flex-wrap:wrap;gap:4px 14px}
.meta b{color:var(--fg);font-weight:600}
.lede{font-size:clamp(20px, 1.1rem + .6vw, 26px);line-height:1.4;letter-spacing:-.015em}
.formula{font-family:var(--font-math);font-style:italic;font-size:clamp(34px, 1.6rem + 2vw, 52px);line-height:1;margin:.6em 0 .2em;letter-spacing:0}
.saber{font-size:var(--fs-small);color:var(--secondary);border-left:1px solid var(--tertiary);padding-left:1.2em}

.toc{font-size:var(--fs-small)}
.toc b{font-weight:600}
.toc ol{margin:.5em 0 0;padding-left:1.2em;columns:2;column-gap:32px}
@media (max-width:560px){ .toc ol{columns:1} }

figure{margin:2em 0}
figcaption{font-size:var(--fs-small);color:var(--secondary);margin-top:.75em}
.fig-row{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:24px}
@media (max-width:560px){ .fig-row{grid-template-columns:1fr} }
svg text{font-family:var(--font-math);fill:var(--fg)}

.formulas{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:0;border-top:1px solid var(--tertiary);border-bottom:1px solid var(--tertiary)}
.formulas div{padding:18px 0}
.formulas div + div{padding-left:20px;border-left:1px solid var(--tertiary)}
@media (max-width:640px){ .formulas{grid-template-columns:1fr} .formulas div + div{padding-left:0;border-left:0;border-top:1px solid var(--tertiary)} }
.formulas small{display:block;font-size:14px;color:var(--secondary)}
.formulas .math{font-size:24px}

.tbl{overflow-x:auto}
table{border-collapse:collapse;width:100%;font-size:var(--fs-small);font-variant-numeric:tabular-nums}
th,td{border-bottom:1px solid var(--tertiary);padding:10px 12px 10px 0;text-align:left;vertical-align:top}
th{color:var(--secondary);font-weight:500}

/* Publicidad: marcador neutro con altura reservada */
.ad{display:grid;place-items:center;background:var(--quaternary);color:var(--secondary);font-size:12px;letter-spacing:.06em;text-transform:uppercase;border-radius:8px}
.ad.in{min-height:280px;margin:2.4em 0}
.ad.side{min-height:600px}
.ad.anchor{position:fixed;left:0;right:0;bottom:0;min-height:calc(56px + env(safe-area-inset-bottom,0px));padding-bottom:env(safe-area-inset-bottom,0px);border-radius:0;border-top:1px solid var(--tertiary);z-index:6}
@media (min-width:1280px){ .ad.anchor{display:none} }

/* Botones (píldora, como Björk) */
.btn{font:inherit;font-size:16px;font-weight:600;border-radius:999px;padding:12px 24px;border:1px solid var(--primary);background:var(--primary);color:#fff;cursor:pointer}
.btn.ghost{background:transparent;color:var(--primary)}

/* Tarjeta de juego */
.game-list{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,300px),1fr));gap:24px}
.game-card{display:flex;flex-direction:column;overflow:hidden;background:var(--quaternary);border-radius:16px;text-decoration:none}
.game-card img{display:block;width:100%;height:auto}
.game-card-body{flex:1;display:grid;grid-template-rows:auto 1fr auto auto;justify-items:start;gap:8px;padding:clamp(20px, 4vw, 32px)}
.game-card-body strong{font-size:var(--fs-h2);font-weight:600;letter-spacing:-.02em;line-height:1.15}
.game-card-body small{font-size:var(--fs-small);color:var(--secondary)}
.game-card-body .btn{margin-top:8px}
.game-card:hover strong{text-decoration:underline}

/* Calculadora y test: superficie gris suave */
.panel{background:var(--quaternary);border-radius:16px;padding:clamp(20px, 4vw, 40px)}
.panel h2{margin-top:0}
.seg{display:flex;flex-wrap:wrap;gap:8px;border:0;margin:0;padding:0}
.seg label{position:relative}
.seg input{position:absolute;opacity:0;inset:0;cursor:pointer}
.seg span{display:inline-block;padding:8px 18px;border-radius:999px;border:1px solid var(--tertiary);background:var(--bg);font-size:16px;font-weight:600}
.seg input:checked + span{background:var(--fg);color:var(--bg);border-color:var(--fg)}
.seg input:focus-visible + span{outline:2px solid var(--primary);outline-offset:2px}
.fields{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px;margin-top:20px}
@media (max-width:600px){ .fields{grid-template-columns:1fr 1fr} }
.field{display:grid;gap:6px;font-size:14px;color:var(--secondary)}
.field input,.field select{font:inherit;font-size:18px;color:var(--fg);background:var(--bg);border:1px solid var(--tertiary);border-radius:10px;padding:10px 12px;width:100%;font-variant-numeric:tabular-nums}
.result{margin-top:24px}
.result .label{font-size:14px;color:var(--secondary)}
.result .r{font-size:clamp(30px, 1.4rem + 1.6vw, 44px);font-weight:600;letter-spacing:-.03em;line-height:1.1}
.result ol{margin:.6em 0 0;padding-left:1.2em;font-family:var(--font-math);font-size:19px}
.result .err{color:var(--bad);font-weight:600}

/* Ejercicios */
.ex{border-top:1px solid var(--tertiary);padding:24px 0}
.ex:last-of-type{border-bottom:1px solid var(--tertiary)}
.ex .head{display:flex;gap:12px;align-items:baseline;font-size:14px;color:var(--secondary)}
.ex .head b{font-size:var(--fs-body);color:var(--fg);font-weight:600}
.ex p{margin:.5em 0 0}
details.sol{margin-top:12px}
details.sol summary{cursor:pointer;color:var(--primary);font-weight:600;font-size:16px;list-style:none;display:inline-block}
details.sol summary::-webkit-details-marker{display:none}
details.sol summary::after{content:" ↓"}
details.sol[open] summary::after{content:" ↑"}
details.sol .body{margin-top:12px;padding:16px 20px;background:var(--quaternary);border-radius:12px}
details.sol .body ol{margin:.2em 0;padding-left:1.2em}
details.sol .body p{margin:.4em 0}

/* Test */
.q{border-top:1px solid var(--tertiary);padding-top:20px;margin-top:20px}
.q fieldset{border:0;margin:0;padding:0}
.q legend{font-weight:600;padding:0;margin-bottom:10px}
.opts{display:grid;gap:8px}
.opt{display:flex;gap:12px;align-items:center;padding:10px 14px;border-radius:12px;background:var(--bg);border:1px solid var(--tertiary);cursor:pointer}
.opt input{accent-color:var(--primary);width:18px;height:18px}
.opt.right{border-color:var(--ok)}
.opt.wrong{border-color:var(--bad)}
.why{font-size:var(--fs-small);color:var(--secondary);margin:.6em 0 0}
.why.good{color:var(--ok)}
.row{display:flex;flex-wrap:wrap;gap:12px;align-items:center;margin-top:24px}
.score{font-weight:600}

/* Descargas */
.files{list-style:none;padding:0;margin:0;border-top:1px solid var(--tertiary)}
.files li{display:flex;justify-content:space-between;gap:16px;align-items:center;padding:16px 0;border-bottom:1px solid var(--tertiary);max-width:none}
.files small{display:block;color:var(--secondary);font-size:14px}
.files .soon{font-size:14px;color:var(--secondary);white-space:nowrap}

/* Docentes y FAQ */
details.fold{border-top:1px solid var(--tertiary);border-bottom:1px solid var(--tertiary)}
details.fold > summary{cursor:pointer;padding:20px 0;font-size:var(--fs-h3);font-weight:600;letter-spacing:-.02em;list-style:none;display:flex;justify-content:space-between;gap:16px}
details.fold > summary::-webkit-details-marker{display:none}
details.fold > summary::after{content:"+";font-weight:400;color:var(--secondary)}
details.fold[open] > summary::after{content:"−"}
details.fold .inner{padding-bottom:24px}
details.fold .inner h3:first-child{margin-top:0}
.faq details{border-top:1px solid var(--tertiary);padding:16px 0}
.faq details:last-child{border-bottom:1px solid var(--tertiary)}
.faq summary{cursor:pointer;font-weight:600}
.faq p{margin:.5em 0 0}

.pn{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:24px;border-top:1px solid var(--tertiary);padding-top:20px}
@media (max-width:560px){ .pn{grid-template-columns:1fr} }
.pn a{text-decoration:none}
.pn a:hover span{text-decoration:underline}
.pn small{display:block;font-size:14px;color:var(--secondary)}
.pn span{font-weight:600;font-size:var(--fs-h3);letter-spacing:-.02em;line-height:1.2}
.pn a:last-child{text-align:right}
@media (max-width:560px){ .pn a:last-child{text-align:left} }
.related{display:flex;flex-wrap:wrap;gap:8px;padding:0;list-style:none}
.related a{display:inline-block;padding:6px 14px;border-radius:999px;border:1px solid var(--tertiary);text-decoration:none;font-size:15px}
.related a:hover{border-color:var(--fg)}
.byline{font-size:var(--fs-small);color:var(--secondary)}
.foot{font-size:14px;color:var(--secondary);padding:0 max(var(--gutter), env(safe-area-inset-right,0px)) 100px max(var(--gutter), env(safe-area-inset-left,0px))}
@media (min-width:1280px){ .foot{margin-left:240px} }
.foot .in{max-width:var(--content);margin:0 auto;border-top:1px solid var(--tertiary);padding-top:20px}