:root{--bg:#020406;--surface:#0c1721;--line:rgba(166,199,212,.13);--line-strong:rgba(166,199,212,.22);--text:#eef8f5;--soft:#b6c8cb;--muted:#7f979f;--emerald:#5ee8a6;--blue:#79d6ff;--xp:#5cc9d6;--bad:#ff8a8a}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--text);font:16px/1.6 'Manrope',system-ui,sans-serif;min-width:320px}
a{color:var(--blue);text-decoration:none}a:hover{text-decoration:underline}
.top-nav{display:flex;flex-wrap:wrap;align-items:center;gap:14px 22px;padding:12px 20px;border-bottom:1px solid var(--line);position:sticky;top:0;background:rgba(2,4,6,.92);backdrop-filter:blur(8px);z-index:5}
.top-nav a{color:var(--soft);font-weight:600;font-size:15px}.top-nav a:hover{color:var(--text);text-decoration:none}
.brand{display:flex;align-items:center;gap:9px;color:var(--text)!important;font-weight:800;font-size:18px}.brand b{color:var(--emerald)}
.brand-mark{display:grid;place-items:center;width:28px;height:28px;border-radius:8px;background:rgba(94,232,166,.12);color:var(--emerald);font-family:Georgia,serif}
.nav-search{margin-left:auto;flex:1 1 220px;max-width:340px}
input[type=search]{width:100%;padding:9px 14px;border-radius:10px;border:1px solid var(--line-strong);background:var(--surface);color:var(--text);font:inherit;font-size:15px}
input[type=search]:focus{outline:2px solid var(--xp);outline-offset:1px}
.page{max-width:820px;margin:0 auto;padding:22px 16px 60px}
.crumbs{font-size:14px;color:var(--muted);margin-bottom:14px;display:flex;flex-wrap:wrap;gap:4px 6px}.crumbs a{color:var(--soft)}.crumbs .sep{opacity:.5}
.card{background:var(--surface);border:1px solid var(--line);border-radius:16px;padding:22px 24px;margin-bottom:16px}
.card.small{font-size:14px;color:var(--soft)}
h1{font-size:clamp(22px,4vw,32px);line-height:1.25;margin:.2em 0 .5em;font-weight:800}
h1 small{font-size:.55em;color:var(--muted);font-weight:500}
h2{font-size:18px;margin:0 0 12px}h2 small{color:var(--muted);font-weight:500;font-size:.8em}
h2 a{color:var(--text)}
.kicker{margin:0;color:var(--emerald);font-size:13px;font-weight:700;letter-spacing:.04em;text-transform:uppercase}
.lead{font-size:18px;color:var(--soft)}
.t-link{color:inherit;text-decoration:underline;text-decoration-color:var(--xp);text-underline-offset:2px;text-decoration-thickness:1px}
.t-link:hover{color:var(--xp);text-decoration-thickness:2px}
.t-self{text-decoration:underline;text-decoration-color:var(--emerald);text-underline-offset:2px;text-decoration-thickness:1px;color:var(--text)}
.formula{margin:14px 0;padding:14px;border-radius:12px;background:rgba(121,214,255,.05);border:1px solid var(--line);overflow-x:auto;text-align:center}
.chips{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0}.chip{padding:3px 10px;border-radius:99px;border:1px solid var(--line-strong);font-size:13px;color:var(--soft)}
.cta{display:inline-block;margin-top:6px;padding:10px 18px;border-radius:10px;background:rgba(94,232,166,.14);border:1px solid rgba(94,232,166,.4);color:var(--emerald);font-weight:700}
.cta:hover{background:rgba(94,232,166,.22);text-decoration:none}
.link-list,.ex-list{margin:0;padding-left:20px}.link-list li,.ex-list li{margin:4px 0}.ex-list{list-style:none;padding:0}.ex-list li a{display:block;padding:7px 10px;border-radius:8px;color:var(--soft)}.ex-list li a:hover{background:rgba(121,214,255,.07);text-decoration:none;color:var(--text)}
.code{font-family:'DM Mono',monospace;font-size:.85em;color:var(--xp)}
.stars{color:#ffd66b;letter-spacing:1px}
.hint{color:var(--muted);font-size:14px}.hint code{font-family:'DM Mono',monospace;color:var(--soft);background:rgba(255,255,255,.05);padding:1px 5px;border-radius:5px}
.options{list-style:none;padding:0;margin:14px 0;display:grid;gap:10px}
.opt{display:flex;gap:12px;align-items:flex-start;width:100%;text-align:left;padding:12px 14px;border-radius:12px;border:1px solid var(--line-strong);background:rgba(255,255,255,.02);color:var(--text);font:inherit;cursor:pointer}
.opt:hover{border-color:var(--xp)}.opt .letter{flex:none;width:26px;height:26px;border-radius:7px;display:grid;place-items:center;background:rgba(121,214,255,.1);color:var(--blue);font-weight:700;font-size:14px}
.opt.sel{border-color:var(--xp);background:rgba(92,201,214,.1)}
.opt.ok{border-color:var(--emerald);background:rgba(94,232,166,.12)}.opt.bad{border-color:var(--bad);background:rgba(255,138,138,.1)}
.answer{margin:12px 0;border:1px dashed var(--line-strong);border-radius:12px;padding:10px 14px}.answer summary{cursor:pointer;font-weight:700;color:var(--soft)}.answer-body{margin-top:8px}.answer-body ul{margin:0;padding-left:18px}
.pager{display:flex;justify-content:space-between;gap:10px}
.grid-list{list-style:none;margin:0;padding:0;display:grid;grid-template-columns:repeat(auto-fill,minmax(230px,1fr));gap:10px}
.grid-list a{display:block;height:100%;padding:12px 14px;border-radius:12px;border:1px solid var(--line);color:var(--soft)}.grid-list a:hover{border-color:var(--xp);text-decoration:none}.grid-list b{display:block;color:var(--text)}.grid-list span{font-size:14px}
.inline-links{line-height:2}
.big-search{display:flex;gap:10px;margin:14px 0}.big-search button{padding:0 20px;border-radius:10px;border:1px solid rgba(94,232,166,.4);background:rgba(94,232,166,.14);color:var(--emerald);font:inherit;font-weight:700;cursor:pointer}
.results{list-style:none;margin:16px 0 0;padding:0;display:grid;gap:8px}.results a{display:block;padding:12px 14px;border-radius:12px;border:1px solid var(--line);color:var(--soft)}.results a:hover{border-color:var(--xp);text-decoration:none}.results b{color:var(--text);display:block;margin:2px 0}.results .meta{font-size:13px;color:var(--muted)}
.badge{display:inline-block;padding:1px 9px;border-radius:99px;font-size:12px;font-weight:700;font-family:'DM Mono',monospace}.badge.concepto{background:rgba(94,232,166,.14);color:var(--emerald)}.badge.ejercicio{background:rgba(121,214,255,.12);color:var(--blue)}
.empty{color:var(--muted)}
.site-footer{border-top:1px solid var(--line);padding:22px 16px;text-align:center;color:var(--muted);font-size:14px}
mjx-container{max-width:100%;overflow-x:auto;overflow-y:hidden}
@media(max-width:560px){.card{padding:16px}.nav-search{max-width:none;flex-basis:100%;order:3}}
.explanation p{margin:0;font-size:17px;color:var(--soft)}
.cta-back{background:rgba(121,214,255,.1);border-color:rgba(121,214,255,.4);color:var(--blue)}
.lang-switch{margin-left:4px;padding:3px 9px;border:1px solid var(--line-strong);border-radius:99px;font-size:13px;font-weight:700;color:var(--blue)!important}
.lang-switch:hover{border-color:var(--xp);text-decoration:none}

/* ---- mismas cajas que la app ---- */
.page{max-width:1040px}
.card{background:linear-gradient(145deg,rgba(14,27,38,.96),rgba(10,20,29,.98));border:1px solid var(--line);border-radius:14px}
.block{margin:26px 0 8px}
.block-title{font-size:13px;margin:0 0 14px;color:var(--emerald);font-family:'DM Mono',monospace;font-weight:500;letter-spacing:.08em;text-transform:uppercase}
.block-title a{color:inherit}
.theory-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(310px,1fr));gap:16px;margin:0 0 18px}
.theory-card{display:flex;flex-direction:column;min-width:0;min-height:237px;padding:22px;border:1px solid var(--line);border-radius:14px;background:linear-gradient(145deg,rgba(14,27,38,.96),rgba(10,20,29,.98))}
.theory-card-heading{margin-bottom:9px}
.theory-card h2{min-width:0;margin:0;color:var(--text);font-size:17px;letter-spacing:-.025em}
.theory-card p{min-height:58px;margin:0 0 18px;color:var(--soft);font-size:13px;line-height:1.6}
.definition-alias{color:var(--muted);font-size:.72em;font-weight:500;letter-spacing:0}
.term-branch-link{color:inherit;text-decoration:underline;text-decoration-color:var(--emerald);text-underline-offset:3px;text-decoration-thickness:1px}
.term-branch-link:hover{color:var(--emerald);text-decoration-thickness:2px}
.formula{margin:auto 0 0;padding:17px 0 0;border:0;border-top:1px solid var(--line);border-radius:0;background:none;color:#e5f8ff;font-family:Georgia,serif;font-size:19px;line-height:1.35;text-align:center;overflow-x:auto;overflow-y:hidden}
.card > .formula{margin-top:18px}
.definition-actions{display:flex;gap:8px;margin-top:14px;padding-top:12px;border-top:1px solid var(--line)}
.definition-actions a{display:grid;grid-auto-flow:column;gap:6px;place-items:center;flex:1 1 0;height:32px;border:1px solid var(--line);border-radius:7px;background:rgba(255,255,255,.025);color:var(--muted);font-size:15px;line-height:1;text-decoration:none;transition:.18s ease}
.definition-actions a:hover{border-color:var(--line-strong);color:var(--text)}
.definition-actions a:nth-child(2){border-color:rgba(184,153,255,.22);background:rgba(184,153,255,.08);color:#b899ff}
.definition-actions a:nth-child(3){border-color:rgba(121,214,255,.24);background:rgba(121,214,255,.08);color:var(--blue)}
.practice-icon{width:16px;height:16px;fill:none;stroke:currentColor;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
.act-count{font:500 12px 'DM Mono',monospace}

/* ---- hoja de ejercicios (estilo libro) ---- */
.worksheet{margin-top:4px}
.ws-concept{margin:0 0 6px;font-size:16px}
.ws-concept a{color:var(--text)}
.ws-concept small{color:var(--muted);font-weight:500}
.ws-title{margin:20px 0 6px;padding-bottom:9px;border-bottom:1px solid var(--line-strong);color:var(--text);font-size:15px;font-weight:800;letter-spacing:-.01em}
.ws-title:first-child{margin-top:8px}
.ws-list{list-style:none;margin:0;padding:0;columns:2;column-gap:56px;counter-reset:ws}
.ws-list li{counter-increment:ws;break-inside:avoid;display:flex;align-items:center;gap:14px;padding:13px 0;border-bottom:1px dotted rgba(166,199,212,.1);font-size:19px}
.ws-list li::before{content:counter(ws) '.';flex:none;min-width:28px;color:var(--muted);font:500 14px 'DM Mono',monospace}
.ws-list a{color:var(--text);text-decoration:none;max-width:100%}
.ws-list mjx-container{overflow:visible!important;margin:0!important}
.ws-list a:hover{color:var(--blue)}
.ws-problems{margin:6px 0 0;padding-left:30px;color:var(--soft)}
.ws-problems li{margin:12px 0;padding-left:4px;line-height:1.55}
.ws-problems a{color:var(--soft);text-decoration:none}
.ws-problems a:hover{color:var(--blue)}
@media(max-width:700px){.ws-list{columns:1}.theory-grid{grid-template-columns:1fr}}

/* ---- Página de concepto tipo libro: barra izquierda, contenido y barra derecha ---- */
.page.page-wide{max-width:1280px}
.concept-layout{display:grid;grid-template-columns:minmax(0,1fr);gap:20px;align-items:start}
.concept-layout.has-left{grid-template-columns:250px minmax(0,1fr)}
.concept-layout.has-right{grid-template-columns:minmax(0,1fr) 230px}
.concept-layout.has-left.has-right{grid-template-columns:250px minmax(0,1fr) 230px}
.concept-main{min-width:0}
.concept-head{border-left:4px solid var(--c,var(--emerald))}
.concept-head h1{margin-bottom:.3em}
.side-left,.side-right{position:sticky;top:74px;max-height:calc(100vh - 90px);overflow:auto;scrollbar-width:thin}
.side-menu{background:var(--surface);border:1px solid var(--line);border-radius:16px;padding:14px}
.side-menu>summary{font-weight:700;font-size:14px;color:var(--soft);cursor:pointer;list-style:none;display:none}
.side-access{display:grid;gap:8px;margin-bottom:14px}
.side-access a{display:flex;flex-direction:column;gap:1px;padding:9px 12px;border:1px solid var(--line-strong);border-radius:12px;color:var(--text)}
.side-access a:hover{border-color:var(--blue);text-decoration:none;background:rgba(121,214,255,.06)}
.side-access small{color:var(--muted);font-size:11px;text-transform:uppercase;letter-spacing:.05em}
.side-access strong{font-size:14px;line-height:1.3}
.side-topic{border-top:1px solid var(--line);padding:6px 0}
.side-topic>summary{display:flex;justify-content:space-between;align-items:center;gap:8px;cursor:pointer;font-weight:700;font-size:13px;color:var(--text);list-style:none;padding:5px 2px;border-left:3px solid var(--c,var(--emerald));padding-left:9px}
.side-topic>summary small{color:var(--muted);font-weight:500}
.side-topic ul{list-style:none;margin:4px 0 6px;padding:0 0 0 12px}
.side-topic li a{display:block;padding:4px 8px;border-radius:8px;color:var(--soft);font-size:13px;line-height:1.35}
.side-topic li a:hover{background:rgba(255,255,255,.04);color:var(--text);text-decoration:none}
.side-topic li.is-current a{background:rgba(94,232,166,.12);color:var(--emerald);font-weight:700}
.side-right{display:grid;gap:8px;background:var(--surface);border:1px solid var(--line);border-radius:16px;padding:14px}
.rail-title{margin:0 0 2px;color:var(--muted);font-size:12px;font-weight:700;text-transform:uppercase;letter-spacing:.05em}
.side-right a{display:flex;gap:10px;align-items:flex-start;padding:9px 10px;border-radius:12px;border:1px dashed var(--line-strong);color:var(--soft)}
.side-right a:hover{border-color:var(--blue);color:var(--text);text-decoration:none;background:rgba(121,214,255,.06)}
.side-right a>span:first-child{display:grid;place-items:center;flex:none;width:26px;height:26px;border-radius:50%;background:rgba(121,214,255,.12);color:var(--blue);font-size:13px}
.side-right strong{display:block;font-size:13px;line-height:1.3;color:var(--text)}
.side-right small{display:block;color:var(--muted);font-size:12px}
.def-box{position:relative;margin-bottom:16px;padding:22px 24px;border-radius:16px;border:1px solid color-mix(in srgb,var(--c,#5ee8a6) 45%,transparent);background:linear-gradient(135deg,color-mix(in srgb,var(--c,#5ee8a6) 11%,var(--surface)),var(--surface));box-shadow:0 0 0 1px rgba(255,255,255,.02),0 12px 36px rgba(0,0,0,.28)}
.def-label{margin:0 0 6px;color:var(--c,var(--emerald));font-size:12px;font-weight:800;letter-spacing:.08em;text-transform:uppercase}
.def-body{margin:0;font-size:18px;line-height:1.7;color:var(--text)}
.def-alias{margin:12px 0 0;color:var(--soft);font-size:14px}.def-alias span{color:var(--muted)}
.def-box .formula{margin-bottom:0}
.sec-label{margin:10px 0 4px;color:var(--muted);font-size:12px;font-weight:700;text-transform:uppercase;letter-spacing:.05em}
.muted{color:var(--muted)}
.book-copy p{margin:0 0 14px;font-size:17px;line-height:1.75;color:var(--soft)}
.think{margin-top:8px}
.context-question{margin:8px 0;padding:10px 14px;border:1px solid var(--line);border-radius:12px;background:rgba(255,255,255,.02)}
.context-question summary{cursor:pointer;font-weight:600;color:var(--text)}
.context-question p{margin:8px 0 0;color:var(--soft)}
.sec-next .cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:18px}
.ref-where{color:var(--muted)}
.link-list{margin:6px 0 0;padding-left:18px}
@media (max-width:1180px){.concept-layout.has-left,.concept-layout.has-left.has-right{grid-template-columns:230px minmax(0,1fr)}.concept-layout.has-right:not(.has-left){grid-template-columns:minmax(0,1fr)}.side-right{grid-column:auto;position:static;max-height:none;grid-template-columns:repeat(auto-fit,minmax(200px,1fr))}.side-right .rail-title{grid-column:1/-1}}
@media (min-width:821px) and (max-width:1180px){.concept-layout.has-left .side-right{grid-column:2}}
@media (max-width:820px){.concept-layout.has-left,.concept-layout.has-left.has-right,.concept-layout.has-right{grid-template-columns:minmax(0,1fr)}.side-left{position:static;max-height:none}.side-menu>summary{display:block}.side-menu[open]>summary{margin-bottom:10px}.side-right{grid-column:1}.def-body{font-size:17px}}
.cols-cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:16px}
.cols-cards .card{margin:0}
.inline-links .cta{margin-top:0}

/* Antes de empezar: prerrequisitos en columnas que se adaptan al ancho */
.req-cols{list-style:none;margin:8px 0 0;padding:0;column-width:190px;column-gap:22px}
.req-cols li{break-inside:avoid;padding:3px 0}
.concept-intro{margin:0 0 16px;font-size:18px;line-height:1.65;color:var(--soft)}
.sec-prior h2{font-size:16px;color:var(--soft)}

/* Páginas de entrada (curso, tema, área): resumen, cifras y botón grande */
.hero h1{margin-bottom:.25em}
.stat-row{display:flex;flex-wrap:wrap;gap:12px 26px;margin:18px 0 6px}
.stat-row>div{display:flex;flex-direction:column;min-width:78px}
.stat-row b{font-size:26px;line-height:1.1;color:var(--text);font-weight:800}
.stat-row span{color:var(--muted);font-size:13px}
.hero-cta{display:flex;flex-wrap:wrap;align-items:center;gap:12px 18px;margin:20px 0 0}
.cta-big{padding:14px 30px;font-size:18px;border-radius:14px;background:rgba(94,232,166,.2);border-color:rgba(94,232,166,.55);box-shadow:0 8px 30px rgba(94,232,166,.12)}
.cta-ghost{padding:12px 18px;border:1px solid var(--line-strong);border-radius:12px;color:var(--soft);font-weight:700}
.cta-ghost:hover{border-color:var(--blue);color:var(--text);text-decoration:none}
.route{list-style:none;margin:10px 0 0;padding:0;display:grid;gap:14px}
.route li{display:flex;gap:14px;align-items:flex-start;padding-left:2px}
.route-num{display:grid;place-items:center;flex:none;width:32px;height:32px;border-radius:50%;border:2px solid var(--c,var(--emerald));color:var(--c,var(--emerald));font:700 14px 'DM Mono',monospace}
.route small{color:var(--muted);margin-left:6px}
.route .inline-links{margin:4px 0 0;color:var(--soft);font-size:14.5px;line-height:1.7}
.concept-list{list-style:none;margin:8px 0 0;padding:0;display:grid;gap:12px}
.concept-list li{padding-bottom:12px;border-bottom:1px solid var(--line)}
.concept-list li:last-child{border-bottom:0;padding-bottom:0}
.concept-list small{margin-left:8px;color:var(--muted)}
.concept-snippet{display:block;margin-top:2px;color:var(--soft);font-size:14.5px}

/* Barra derecha en dos cajas */
.side-right{background:none!important;border:0!important;padding:0!important;display:grid;gap:14px}
.rail-box{display:grid;gap:8px;background:var(--surface);border:1px solid var(--line);border-radius:16px;padding:14px}
.req-cols li{position:relative;padding-left:18px}
.req-cols li::before{content:'';position:absolute;left:3px;top:.8em;width:7px;height:7px;border-radius:50%;background:var(--c,var(--emerald));box-shadow:0 0 0 3px color-mix(in srgb,var(--c,var(--emerald)) 22%,transparent)}
.course-grid{grid-template-columns:repeat(auto-fit,minmax(min(100%,340px),1fr))}
.course-card h2{margin:0 0 6px;font-size:21px}
.course-summary{margin:0;color:var(--soft)}

/* Conceptos prestados: viven en otro curso (data/courses/PRESTAMOS.json) */
.borrow{display:inline-block;margin-left:4px;padding:1px 7px;border-radius:999px;border:1px solid rgba(245,190,80,.55);background:rgba(245,190,80,.10);color:#f5be50;font-size:11px;font-weight:600;line-height:1.5;vertical-align:1px;white-space:nowrap}
a.borrow:hover{background:rgba(245,190,80,.2);text-decoration:none}
.side-topic li a .borrow{margin-left:0;margin-top:2px;padding:0 6px;font-size:10px}
.prereq{margin:8px 0 0;padding:8px 12px;border-radius:10px;border:1px dashed rgba(245,190,80,.5);color:var(--soft);font-size:14px}
.prereq span{color:#f5be50;font-weight:700}
.prereq small{display:block;color:var(--muted);margin-top:2px}

.building{display:inline-block;margin:6px 0 4px;padding:4px 10px;border-radius:999px;border:1px solid rgba(245,190,80,.55);background:rgba(245,190,80,.08);color:var(--soft);font-size:13px}
.building span{color:#f5be50;font-weight:700}