/* ─── Reset y base ─────────────────────────────────────────────────────────── */
*,*::before,*::after{box-sizing:border-box}
html{
  -webkit-text-size-adjust:100%;
  text-size-adjust:100%;
  scroll-behavior:smooth;
}
body{
  margin:0;
  font-family:'Inter',system-ui,-apple-system,'Segoe UI',sans-serif;
  font-feature-settings:'cv11','ss01','ss03';
  background:var(--bg);
  color:var(--text);
  line-height:1.6;
  font-size:17px;
  -webkit-font-smoothing:antialiased;
  text-rendering:optimizeLegibility;
}
img,svg{display:block;max-width:100%}
button{font:inherit;color:inherit;background:none;border:0;cursor:pointer}
input,select,textarea{font:inherit;color:inherit}

/* ─── Tema ─────────────────────────────────────────────────────────────────── */
:root{
  --bg:           #0b0f1d;
  --bg-elev:      #131a2e;
  --bg-elev-2:    #1c2540;
  --bg-card:      #161e36;
  --border:       rgba(255,255,255,0.08);
  --border-strong:rgba(255,255,255,0.16);
  --text:         #f0eadb;
  --text-soft:    #c4c8d8;
  --text-muted:   #8a91a8;
  --text-faint:   #5d6378;

  --sun:          #f4a13b;
  --sun-soft:     #ffce7b;
  --sun-deep:     #d97a17;
  --sky:          #5cc7ee;
  --sky-deep:     #2a82a9;
  --shadow-c:     #6c5ce7;
  --shadow-soft:  #a29bfe;
  --grass:        #6ec77c;
  --warn:         #ffb86b;
  --danger:       #ff6b8a;

  --radius:       14px;
  --radius-sm:    8px;
  --shadow-1:     0 4px 24px -8px rgba(0,0,0,.5),0 2px 8px -4px rgba(0,0,0,.4);
  --shadow-2:     0 12px 48px -12px rgba(0,0,0,.6),0 4px 16px -6px rgba(0,0,0,.4);
  --shadow-glow:  0 0 32px -4px var(--sun);

  --font-prose:   'Source Serif 4','Crimson Pro',Georgia,serif;
  --font-display: 'Source Serif 4','Crimson Pro',Georgia,serif;
}

/* ─── Tipografía editorial ─────────────────────────────────────────────────── */
h1,h2,h3,h4{
  font-family:var(--font-display);
  font-weight:600;
  letter-spacing:-0.02em;
  line-height:1.15;
  margin:0 0 .5em;
  color:var(--text);
}
h1{font-size:clamp(2rem,5vw + 1rem,4rem);font-weight:600;letter-spacing:-0.035em}
h2{font-size:clamp(1.6rem,2.5vw + 1rem,2.4rem);margin-top:2.2em}
h3{font-size:clamp(1.25rem,1vw + 1rem,1.5rem);margin-top:2em}
h4{font-size:1.1rem;margin-top:1.5em;color:var(--text-soft)}
p{margin:0 0 1em}
a{color:var(--sun);text-decoration:none;border-bottom:1px solid rgba(244,161,59,.3);transition:.15s}
a:hover{color:var(--sun-soft);border-bottom-color:var(--sun)}
strong{color:var(--text);font-weight:600}
em{color:var(--sun-soft);font-style:italic}
code{
  font-family:ui-monospace,'SF Mono',Menlo,Consolas,monospace;
  font-size:.92em;
  background:var(--bg-elev);
  padding:.12em .4em;
  border-radius:4px;
  color:var(--sun-soft);
}

/* ─── Layout principal ─────────────────────────────────────────────────────── */
.shell{
  max-width:1280px;
  margin:0 auto;
  padding:0 24px;
}
.prose{
  max-width:720px;
  margin:0 auto;
  font-family:var(--font-prose);
  font-size:1.18rem;
  line-height:1.7;
  color:var(--text-soft);
}
.prose h2,.prose h3,.prose h4{font-family:var(--font-display)}

.wide{max-width:980px;margin-left:auto;margin-right:auto}
.full{margin-left:calc(-50vw + 50%);width:100vw}

/* ─── Top nav ───────────────────────────────────────────────────────────────── */
.topnav{
  position:sticky;top:0;z-index:50;
  backdrop-filter:saturate(160%) blur(12px);
  -webkit-backdrop-filter:saturate(160%) blur(12px);
  background:rgba(11,15,29,.7);
  border-bottom:1px solid var(--border);
}
.topnav-inner{
  max-width:1280px;margin:0 auto;
  padding:14px 24px;
  display:flex;align-items:center;gap:24px;
}
.brand{
  display:flex;align-items:center;gap:10px;
  font-family:var(--font-display);font-weight:600;font-size:1.1rem;
  color:var(--text);text-decoration:none;border:0;
}
.brand .sun-mark{
  width:28px;height:28px;border-radius:50%;
  background:radial-gradient(circle at 35% 35%,var(--sun-soft),var(--sun) 60%,var(--sun-deep) 100%);
  box-shadow:0 0 16px -2px var(--sun);
}
.topnav .links{display:flex;gap:18px;margin-left:auto;flex-wrap:wrap}
.topnav .links a{
  color:var(--text-muted);
  border:0;font-size:.95rem;
  padding:6px 0;
}
.topnav .links a:hover{color:var(--text)}
.topnav .links a.active{color:var(--sun)}

/* ─── Hero ──────────────────────────────────────────────────────────────────── */
.hero{
  position:relative;overflow:hidden;
  padding:90px 0 60px;
  text-align:center;
}
.hero h1{
  font-size:clamp(2.4rem,6vw + 1rem,5rem);
  font-weight:500;
  margin-bottom:.4em;
}
.hero .lead{
  font-family:var(--font-prose);
  font-size:clamp(1.1rem,1.5vw + .8rem,1.5rem);
  color:var(--text-soft);
  max-width:640px;margin:0 auto 2em;
  line-height:1.5;
}
.hero-sun{
  position:absolute;inset:0;z-index:-1;
  pointer-events:none;
}

.eyebrow{
  display:inline-block;
  text-transform:uppercase;
  letter-spacing:.2em;
  font-size:.78rem;
  font-weight:600;
  color:var(--sun);
  margin-bottom:1em;
}

/* ─── Grid de capítulos ─────────────────────────────────────────────────────── */
.chapter-grid{
  display:grid;
  grid-template-columns:repeat(auto-fit,minmax(260px,1fr));
  gap:18px;
  margin:48px 0;
}
.chapter-card{
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:24px;
  text-decoration:none;color:inherit;
  display:flex;flex-direction:column;gap:12px;
  transition:transform .25s,border-color .25s,box-shadow .25s;
  position:relative;overflow:hidden;
}
.chapter-card::before{
  content:'';position:absolute;
  inset:-1px -1px auto auto;
  width:160px;height:160px;
  background:radial-gradient(circle at 100% 0,var(--sun) 0%,transparent 60%);
  opacity:.08;transition:opacity .35s;
}
.chapter-card:hover{
  transform:translateY(-3px);
  border-color:var(--border-strong);
  box-shadow:var(--shadow-2);
}
.chapter-card:hover::before{opacity:.18}
.chapter-card .num{
  font-family:var(--font-display);
  font-size:2.4rem;color:var(--sun);
  line-height:1;letter-spacing:-.02em;
  font-weight:500;
}
.chapter-card .title{
  font-family:var(--font-display);
  font-size:1.35rem;font-weight:600;
  letter-spacing:-.02em;
  color:var(--text);
}
.chapter-card .desc{font-size:.95rem;color:var(--text-muted);line-height:1.5}
.chapter-card .meta{
  margin-top:auto;
  font-size:.82rem;color:var(--text-faint);
  display:flex;gap:8px;align-items:center;
  text-transform:uppercase;letter-spacing:.12em;
}
.chapter-card .arrow{margin-left:auto;color:var(--sun);transition:transform .2s}
.chapter-card:hover .arrow{transform:translateX(4px)}

/* ─── Capítulo: layout y header ────────────────────────────────────────────── */
.chapter-header{
  padding:80px 0 30px;
  text-align:center;
  border-bottom:1px solid var(--border);
  margin-bottom:60px;
}
.chapter-header h1{margin-bottom:.4em}
.chapter-header .meta{
  display:flex;gap:20px;justify-content:center;
  font-size:.85rem;color:var(--text-muted);
  text-transform:uppercase;letter-spacing:.15em;
  margin-top:1.4em;
}
.chapter-header .meta span{display:flex;align-items:center;gap:6px}

.chapter-body{padding-bottom:80px}

/* ─── Widgets / cards interactivas ──────────────────────────────────────────── */
.widget{
  margin:48px auto;
  max-width:980px;
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:24px;
  box-shadow:var(--shadow-1);
  font-family:'Inter',system-ui,sans-serif;
  font-size:.95rem;
  color:var(--text);
}
.widget h3,.widget h4{font-family:'Inter',system-ui,sans-serif;letter-spacing:-.01em;margin-top:0}
.widget .widget-title{
  display:flex;align-items:center;gap:10px;
  font-size:1.05rem;font-weight:600;
  color:var(--text);margin:0 0 .8em;
}
.widget .widget-title::before{
  content:'';width:8px;height:8px;border-radius:50%;
  background:var(--sun);box-shadow:0 0 12px var(--sun);
}
.widget .widget-sub{
  color:var(--text-muted);font-size:.92rem;margin:-.4em 0 1.2em;
}

/* Layout de widget con controles a un lado */
.widget-grid{
  display:grid;
  grid-template-columns:1fr 280px;
  gap:24px;align-items:start;
}
@media(max-width:760px){
  .widget-grid{grid-template-columns:1fr}
}
.widget-stage{
  background:var(--bg-elev);
  border-radius:var(--radius-sm);
  padding:14px;
  min-height:280px;
  position:relative;overflow:hidden;
}
.widget-controls{
  display:flex;flex-direction:column;gap:14px;
}

/* Slider con etiqueta y valor en vivo */
.field{
  display:flex;flex-direction:column;gap:6px;
}
.field-row{
  display:flex;justify-content:space-between;align-items:baseline;
  font-size:.85rem;color:var(--text-muted);
}
.field-row .name{font-weight:500;color:var(--text-soft);text-transform:none;letter-spacing:0}
.field-row .value{
  font-variant-numeric:tabular-nums;
  color:var(--sun);font-weight:600;
}
input[type=range]{
  -webkit-appearance:none;appearance:none;
  width:100%;height:24px;background:transparent;
  margin:0;padding:0;
}
input[type=range]:focus{outline:none}
input[type=range]::-webkit-slider-runnable-track{
  height:6px;border-radius:3px;
  background:linear-gradient(to right,var(--sun) var(--p,50%),var(--bg-elev-2) var(--p,50%));
}
input[type=range]::-moz-range-track{
  height:6px;border-radius:3px;
  background:linear-gradient(to right,var(--sun) var(--p,50%),var(--bg-elev-2) var(--p,50%));
}
input[type=range]::-webkit-slider-thumb{
  -webkit-appearance:none;appearance:none;
  width:18px;height:18px;border-radius:50%;
  background:var(--text);
  border:3px solid var(--sun);
  margin-top:-7px;cursor:grab;
  box-shadow:0 2px 6px rgba(0,0,0,.4);
  transition:transform .12s;
}
input[type=range]:active::-webkit-slider-thumb{transform:scale(1.15);cursor:grabbing}
input[type=range]::-moz-range-thumb{
  width:18px;height:18px;border-radius:50%;
  background:var(--text);border:3px solid var(--sun);
  box-shadow:0 2px 6px rgba(0,0,0,.4);
}
input[type=number],input[type=text],select{
  background:var(--bg-elev-2);
  border:1px solid var(--border);
  border-radius:6px;
  padding:6px 10px;
  font-family:'Inter',system-ui;
  font-size:.92rem;
  width:100%;
}
input:focus,select:focus{border-color:var(--sun);outline:none}

button.btn{
  padding:8px 16px;border-radius:6px;
  background:var(--bg-elev-2);
  border:1px solid var(--border);
  color:var(--text);
  font-size:.9rem;font-weight:500;
  transition:.15s;
  display:inline-flex;align-items:center;gap:6px;
}
button.btn:hover{background:var(--bg-elev);border-color:var(--border-strong)}
button.btn-primary{
  background:var(--sun);color:#1a1106;
  border-color:var(--sun-deep);font-weight:600;
}
button.btn-primary:hover{background:var(--sun-soft);color:#1a1106}
button.btn-ghost{background:transparent;border:0}
.btn-row{display:flex;gap:8px;flex-wrap:wrap}

/* Toggle pill group */
.pill-group{display:flex;background:var(--bg-elev-2);border-radius:8px;padding:3px;gap:2px}
.pill-group button{
  flex:1;padding:6px 10px;font-size:.85rem;color:var(--text-muted);
  border-radius:6px;font-weight:500;
}
.pill-group button.active{background:var(--bg-card);color:var(--text);box-shadow:var(--shadow-1)}

/* ─── Callouts ─────────────────────────────────────────────────────────────── */
.callout{
  border-left:3px solid var(--sun);
  background:rgba(244,161,59,.07);
  padding:18px 22px;
  margin:32px auto;
  max-width:720px;
  border-radius:0 var(--radius-sm) var(--radius-sm) 0;
  font-family:var(--font-prose);
  font-size:1.05rem;
  line-height:1.6;
}
.callout.def{border-color:var(--sky);background:rgba(92,199,238,.06)}
.callout.warn{border-color:var(--warn);background:rgba(255,184,107,.07)}
.callout.note{border-color:var(--shadow-soft);background:rgba(162,155,254,.06)}
.callout-label{
  display:block;
  font-family:'Inter',sans-serif;
  font-size:.7rem;font-weight:700;
  letter-spacing:.2em;text-transform:uppercase;
  color:var(--sun);margin-bottom:.5em;
}
.callout.def .callout-label{color:var(--sky)}
.callout.warn .callout-label{color:var(--warn)}
.callout.note .callout-label{color:var(--shadow-soft)}
.callout p:last-child{margin-bottom:0}

/* ─── Fórmulas (KaTeX wrapper) ─────────────────────────────────────────────── */
.formula{
  margin:28px auto;
  max-width:720px;
  text-align:center;
  font-size:1.18rem;
  padding:14px 0;
}
.formula-block{
  margin:32px auto;
  max-width:720px;
  background:var(--bg-elev);
  border:1px solid var(--border);
  border-radius:var(--radius-sm);
  padding:24px 30px;
  text-align:center;
  position:relative;
}
.formula-block .label{
  display:block;
  font-family:'Inter',sans-serif;
  font-size:.7rem;font-weight:700;
  letter-spacing:.2em;text-transform:uppercase;
  color:var(--sky);margin-bottom:.6em;
}
.katex{font-size:1.1em !important;color:var(--text)}
.katex-display{margin:.4em 0 !important}
.katex-display>.katex{color:var(--text);font-size:1.3em !important}

/* ─── Quizzes / checkpoints ────────────────────────────────────────────────── */
.checkpoint{
  margin:44px auto;
  max-width:720px;
  background:linear-gradient(180deg,var(--bg-card),var(--bg-elev));
  border:1px solid var(--border-strong);
  border-radius:var(--radius);
  padding:28px 32px;
}
.checkpoint .title{
  font-family:'Inter',sans-serif;
  font-size:.78rem;letter-spacing:.2em;text-transform:uppercase;
  color:var(--shadow-soft);margin-bottom:1em;font-weight:700;
  display:flex;align-items:center;gap:8px;
}
.checkpoint .question{
  font-family:var(--font-display);
  font-size:1.3rem;line-height:1.4;
  color:var(--text);margin-bottom:1.2em;letter-spacing:-.01em;
}
.checkpoint .options{display:flex;flex-direction:column;gap:8px;margin-bottom:1em}
.checkpoint .opt{
  text-align:left;
  border:1px solid var(--border);
  border-radius:8px;
  padding:12px 16px;
  background:var(--bg-elev-2);
  color:var(--text-soft);
  font-size:1rem;
  display:flex;align-items:center;gap:12px;
  transition:.15s;
}
.checkpoint .opt:hover:not(:disabled){border-color:var(--border-strong);background:var(--bg-elev)}
.checkpoint .opt[data-state="correct"]{
  border-color:var(--grass);background:rgba(110,199,124,.12);color:var(--text);
}
.checkpoint .opt[data-state="wrong"]{
  border-color:var(--danger);background:rgba(255,107,138,.1);color:var(--text);
}
.checkpoint .opt .marker{
  width:24px;height:24px;border-radius:50%;
  border:1px solid var(--border-strong);flex:none;
  display:flex;align-items:center;justify-content:center;
  font-size:.78rem;color:var(--text-muted);font-weight:600;
}
.checkpoint .opt[data-state="correct"] .marker{background:var(--grass);color:#0c1a10;border-color:var(--grass)}
.checkpoint .opt[data-state="wrong"] .marker{background:var(--danger);color:#1a0808;border-color:var(--danger)}
.checkpoint .feedback{
  font-family:var(--font-prose);font-size:1.02rem;
  color:var(--text-soft);line-height:1.55;
  padding-top:.4em;display:none;
}
.checkpoint.answered .feedback{display:block}

/* ─── Navegación capítulos (footer) ────────────────────────────────────────── */
.chapter-nav{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:14px;
  margin:80px auto 40px;
  max-width:980px;
  padding:0 24px;
}
.chapter-nav a{
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:18px 22px;
  display:flex;flex-direction:column;gap:4px;
  text-decoration:none;color:inherit;
  background:var(--bg-card);
  transition:.18s;
  border-bottom:0;
}
.chapter-nav a:hover{border-color:var(--border-strong);background:var(--bg-elev)}
.chapter-nav .label{font-size:.72rem;text-transform:uppercase;letter-spacing:.2em;color:var(--text-faint);margin:0}
.chapter-nav .name{font-family:var(--font-display);font-size:1.15rem;font-weight:600;color:var(--text);letter-spacing:-.01em}
.chapter-nav .next{text-align:right}
.chapter-nav .prev:empty,.chapter-nav .next:empty{visibility:hidden}
@media(max-width:600px){
  .chapter-nav{grid-template-columns:1fr}
}

/* ─── Footer ───────────────────────────────────────────────────────────────── */
.site-footer{
  border-top:1px solid var(--border);
  padding:40px 24px;
  text-align:center;
  font-size:.85rem;color:var(--text-muted);
  margin-top:60px;
}
.site-footer p{margin:.3em 0}

/* ─── Tabla de variables ───────────────────────────────────────────────────── */
.var-table{
  width:100%;
  border-collapse:collapse;
  font-size:.95rem;
  margin:24px 0;
}
.var-table th,.var-table td{
  padding:10px 14px;
  text-align:left;
  border-bottom:1px solid var(--border);
  vertical-align:top;
}
.var-table th{
  color:var(--text-muted);
  font-weight:600;font-size:.8rem;
  text-transform:uppercase;letter-spacing:.12em;
}
.var-table td:first-child{
  font-family:var(--font-prose);font-size:1.1rem;
  color:var(--sun);font-style:italic;width:60px;
}

/* ─── KaTeX inline ajustes ─────────────────────────────────────────────────── */
.katex .mathnormal{color:var(--sun-soft)}

/* ─── Animaciones ───────────────────────────────────────────────────────────── */
@keyframes pulse{0%,100%{opacity:.6}50%{opacity:1}}
@keyframes slow-rotate{to{transform:rotate(360deg)}}
@keyframes fade-up{from{opacity:0;transform:translateY(8px)}to{opacity:1;transform:none}}

.fade-in{animation:fade-up .5s both}
.fade-in-2{animation:fade-up .5s both;animation-delay:.1s}
.fade-in-3{animation:fade-up .5s both;animation-delay:.2s}

/* ─── SVG paleta utilitaria ─────────────────────────────────────────────────── */
.sun-fill{fill:var(--sun)}
.sun-stroke{stroke:var(--sun)}
.shadow-fill{fill:rgba(108,92,231,.55)}
.shadow-stroke{stroke:var(--shadow-c)}
.ground-stroke{stroke:var(--text-faint)}
.guide-stroke{stroke:var(--text-faint);stroke-dasharray:4 4}
.text-svg{fill:var(--text-muted);font-family:'Inter',sans-serif;font-size:11px}
.text-svg-strong{fill:var(--text);font-family:'Inter',sans-serif;font-size:13px;font-weight:600}

/* ─── Misceláneos ──────────────────────────────────────────────────────────── */
.tag{
  display:inline-block;font-size:.7rem;font-weight:700;letter-spacing:.18em;
  text-transform:uppercase;padding:3px 10px;border-radius:999px;
  background:var(--bg-elev-2);color:var(--text-muted);
  border:1px solid var(--border);
}
.tag.sun{background:rgba(244,161,59,.12);color:var(--sun);border-color:rgba(244,161,59,.3)}
.tag.sky{background:rgba(92,199,238,.1);color:var(--sky);border-color:rgba(92,199,238,.3)}

.divider{
  height:1px;background:var(--border);margin:60px auto;max-width:720px;
}

.sr-only{
  position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;
  clip:rect(0,0,0,0);white-space:nowrap;border:0;
}

/* ─── Carta solar SVG ──────────────────────────────────────────────────────── */
.sunchart{user-select:none}
.sunchart .grid{stroke:var(--text-faint);stroke-opacity:.35;fill:none}
.sunchart .horizon{stroke:var(--text-muted);stroke-width:1.5;fill:none}
.sunchart .azimuth-line{stroke:var(--text-faint);stroke-opacity:.25}
.sunchart .altitude-circle{stroke:var(--text-faint);stroke-opacity:.25;fill:none}
.sunchart .path-line{stroke:var(--sun-soft);stroke-width:1.5;fill:none;stroke-opacity:.55}
.sunchart .path-line.solstice{stroke:var(--sun);stroke-width:2;stroke-opacity:1}
.sunchart .path-line.equinox{stroke:var(--sky);stroke-width:2;stroke-opacity:1}
.sunchart .hour-line{stroke:var(--shadow-soft);stroke-width:1;stroke-opacity:.45;fill:none;stroke-dasharray:3 3}
.sunchart .label{fill:var(--text-muted);font-family:'Inter',sans-serif;font-size:11px}
.sunchart .label-strong{fill:var(--text);font-family:'Inter',sans-serif;font-size:12px;font-weight:600}
.sunchart .sun-dot{fill:var(--sun);stroke:#fff;stroke-width:1.5;filter:drop-shadow(0 0 6px var(--sun))}
.sunchart .mask-fill{fill:rgba(108,92,231,.35);stroke:var(--shadow-c);stroke-width:1.2}

/* ─── Diagramas auxiliares ─────────────────────────────────────────────────── */
.legend{
  display:flex;flex-wrap:wrap;gap:14px;
  font-size:.85rem;color:var(--text-muted);
  margin-top:8px;
}
.legend span{display:inline-flex;align-items:center;gap:6px}
.legend .swatch{width:14px;height:3px;border-radius:2px;display:inline-block}
.swatch.sun{background:var(--sun)}
.swatch.sky{background:var(--sky)}
.swatch.shadow{background:var(--shadow-c)}
.swatch.path{background:var(--sun-soft);opacity:.7}

/* ─── Responsive ajustes ───────────────────────────────────────────────────── */
@media(max-width:600px){
  body{font-size:16px}
  .prose{font-size:1.06rem}
  .widget{padding:18px;margin:36px auto}
  .formula-block{padding:18px 14px}
  .topnav .links{gap:10px;font-size:.85rem}
  .chapter-header{padding:60px 0 20px;margin-bottom:40px}
}

/* ─── Toggle del editor de obstáculos ──────────────────────────────────────── */
.obs-list{display:flex;flex-direction:column;gap:6px;max-height:200px;overflow:auto}
.obs-item{
  display:flex;align-items:center;gap:8px;
  padding:6px 10px;background:var(--bg-elev-2);border-radius:6px;
  font-size:.85rem;color:var(--text-soft);
}
.obs-item button{margin-left:auto;color:var(--danger);font-size:.85rem}

/* ─── Stage 3D contenedor ──────────────────────────────────────────────────── */
.stage-3d{
  width:100%;
  aspect-ratio:4/3;
  background:linear-gradient(180deg,#0c1430 0%,#1a2548 60%,#2c3358 100%);
  border-radius:var(--radius-sm);
  position:relative;overflow:hidden;
  cursor:grab;
}
.stage-3d:active{cursor:grabbing}
.stage-3d canvas{display:block;width:100%;height:100%}

/* ─── Comparativa lado a lado ─────────────────────────────────────────────── */
.split{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:20px;
  margin:32px 0;
}
@media(max-width:680px){.split{grid-template-columns:1fr}}
.split>div{
  background:var(--bg-card);
  border:1px solid var(--border);
  border-radius:var(--radius-sm);
  padding:14px;
}
.split h4{font-family:'Inter',sans-serif;font-size:.78rem;letter-spacing:.18em;
  text-transform:uppercase;color:var(--text-muted);margin:0 0 10px;font-weight:600}

/* ─── Visibilidad del scroll de capítulos ──────────────────────────────────── */
.toc{
  position:sticky;top:80px;
  font-size:.85rem;
  padding-left:8px;border-left:2px solid var(--border);
  margin:0;
}
.toc li{list-style:none;margin:6px 0}
.toc a{color:var(--text-muted);border:0}
.toc a:hover{color:var(--text)}
.toc a.active{color:var(--sun)}
@media(max-width:1080px){.toc-wrap{display:none}}

/* ─── Layout columna principal con TOC opcional ────────────────────────────── */
.with-toc{
  display:grid;
  grid-template-columns:1fr min(720px,calc(100% - 40px)) 1fr;
  gap:0;
}
.with-toc>.toc-wrap{padding:80px 24px 0}
.with-toc>.col-main{grid-column:2}
@media(max-width:1080px){
  .with-toc{display:block}
  .with-toc>.col-main{max-width:720px;margin:0 auto}
}