/* ============================================================================
 *  styles.css — Base, layout i components d'Aplicacions Web (reutilitzat de PXSI II)
 *  Variables de color a themes.css (data-theme al <body>)
 * ==========================================================================*/
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}

:root{
  --radius:16px; --radius-sm:10px;
  --ease:cubic-bezier(.22,.8,.22,1);
  --maxw:1180px;
  --font:'Outfit',system-ui,-apple-system,Segoe UI,Roboto,sans-serif;
  --mono:'JetBrains Mono',ui-monospace,Consolas,monospace;
}

html{scroll-behavior:smooth}
body{
  font-family:var(--font);
  background:var(--bg);
  color:var(--text);
  line-height:1.6;
  min-height:100vh;
  -webkit-font-smoothing:antialiased;
}
a{color:inherit;text-decoration:none}
img{max-width:100%;display:block}
button{font-family:inherit;cursor:pointer;border:none;background:none;color:inherit}
select{font-family:inherit}
::selection{background:var(--accent);color:#fff}

/* ─── Capçalera ──────────────────────────────────────────────────────────── */
.topbar{
  position:sticky;top:0;z-index:50;
  background:var(--bg-bar);
  backdrop-filter:blur(12px);
  border-bottom:1px solid var(--border);
}
.topbar-inner{
  max-width:var(--maxw);margin:0 auto;
  display:flex;align-items:center;gap:1rem;
  padding:.65rem 1.25rem;
}
.brand{display:flex;align-items:center;gap:.7rem;margin-right:auto}
.brand-logo{
  display:grid;place-items:center;width:40px;height:40px;font-size:1.4rem;
  border-radius:11px;background:var(--accent-soft);
}
.brand-text strong{display:block;font-size:1.02rem;letter-spacing:-.01em}
.brand-text small{display:block;font-size:.72rem;color:var(--text-dim)}

.mainnav{display:flex;align-items:center;gap:.35rem}
.mainnav a{
  padding:.5rem .8rem;border-radius:9px;font-size:.9rem;font-weight:500;
  color:var(--text-dim);transition:.15s var(--ease);
}
.mainnav a:hover{color:var(--text);background:var(--hover)}
.mainnav a.active{color:var(--accent);background:var(--accent-soft)}

.theme-select select{
  font-family:inherit;font-size:.85rem;
  background:var(--bg-card);color:var(--text);
  border:1px solid var(--border);border-radius:9px;
  padding:.45rem .5rem;cursor:pointer;
}

.hamburger{display:none;flex-direction:column;gap:5px;padding:.5rem}
.hamburger span{width:24px;height:2px;background:var(--text);border-radius:2px;transition:.25s var(--ease)}
.hamburger.active span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.hamburger.active span:nth-child(2){opacity:0}
.hamburger.active span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}

/* ─── Layout general ─────────────────────────────────────────────────────── */
.view{max-width:var(--maxw);margin:0 auto;padding:2.2rem 1.25rem 4rem;min-height:60vh}
.loading{display:grid;place-items:center;gap:1rem;padding:6rem 0;color:var(--text-dim)}
.spinner{width:38px;height:38px;border:3px solid var(--border);border-top-color:var(--accent);border-radius:50%;animation:spin .8s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}

.page-head{margin-bottom:1.6rem}
.page-head h1{font-size:1.9rem;letter-spacing:-.02em}
.page-head .sub{color:var(--text-dim);margin-top:.3rem}
.section-title{font-size:1.4rem;margin:2.2rem 0 1.1rem;letter-spacing:-.01em}
.empty{color:var(--text-dim);padding:2rem;text-align:center;font-style:italic}

/* ─── Botons ─────────────────────────────────────────────────────────────── */
.btn{
  display:inline-flex;align-items:center;gap:.5rem;
  padding:.7rem 1.2rem;border-radius:11px;font-weight:600;font-size:.95rem;
  transition:.18s var(--ease);border:1px solid transparent;
}
.btn-primary{background:var(--accent);color:#fff}
.btn-primary:hover{filter:brightness(1.08);transform:translateY(-1px)}
.btn-ghost{background:var(--bg-card);border-color:var(--border);color:var(--text)}
.btn-ghost:hover{background:var(--hover)}

/* ─── Hero ───────────────────────────────────────────────────────────────── */
.hero{
  display:grid;grid-template-columns:1.1fr .9fr;gap:2.5rem;align-items:center;
  padding:1.5rem 0 2.5rem;
}
.pill{
  display:inline-block;padding:.35rem .8rem;border-radius:999px;
  background:var(--accent-soft);color:var(--accent);
  font-size:.78rem;font-weight:600;margin-bottom:1rem;
}
.hero h1{font-size:2.6rem;line-height:1.1;letter-spacing:-.03em}
.grad{background:linear-gradient(120deg,var(--accent),var(--accent2));-webkit-background-clip:text;background-clip:text;color:transparent}
.lead{color:var(--text-dim);font-size:1.08rem;margin:1.1rem 0 1.6rem;max-width:34rem}
.hero-actions{display:flex;gap:.8rem;flex-wrap:wrap}
.hero-art{display:grid;place-items:center}

/* ─── Graella d'unitats ──────────────────────────────────────────────────── */
.unitgrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(270px,1fr));gap:1.1rem}
.trimester-block{margin-bottom:2.4rem}
.trimester-title{font-size:1.1rem;font-weight:700;color:var(--text-dim);margin-bottom:.9rem;
  display:flex;align-items:center;gap:.6rem}
.trimester-title::after{content:"";flex:1;height:1px;background:var(--border)}
.unitcard{
  position:relative;display:flex;gap:.9rem;
  background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);
  padding:1.2rem;overflow:hidden;transition:.2s var(--ease);
}
.unitcard::before{content:"";position:absolute;inset:0 auto 0 0;width:4px;background:var(--uc)}
.unitcard:hover{transform:translateY(-3px);border-color:var(--uc);box-shadow:0 12px 30px -12px var(--uc)}
.unitcard-num{
  flex:none;width:34px;height:34px;border-radius:9px;
  display:grid;place-items:center;font-weight:800;font-family:var(--mono);
  background:color-mix(in srgb,var(--uc) 18%,transparent);color:var(--uc);
}
.unitcard-ico{font-size:1.3rem}
.unitcard-body h3{font-size:1.05rem;margin:.2rem 0 .3rem;letter-spacing:-.01em}
.unitcard-body p{color:var(--text-dim);font-size:.85rem;line-height:1.45}
.unitcard-meta{display:flex;gap:.6rem;align-items:center;margin-top:.6rem;font-size:.76rem;color:var(--text-muted)}

/* ─── Ajuda portada ──────────────────────────────────────────────────────── */
.home-help{display:grid;grid-template-columns:1fr 1fr;gap:1.1rem;margin-top:2.5rem}
.help-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);padding:1.3rem}
.help-card h3{margin-bottom:.5rem;font-size:1.05rem}
.help-card p{color:var(--text-dim);font-size:.92rem}
.help-card a{color:var(--accent);font-weight:600}

/* ─── Capçalera d'unitat + pestanyes ──────────────────────────────────────── */
.unit-head{border-bottom:1px solid var(--border);padding-bottom:0;margin-bottom:1.5rem}
.back{color:var(--text-dim);font-size:.88rem;display:inline-block;margin-bottom:1rem}
.back:hover{color:var(--accent)}
.unit-title{display:flex;align-items:center;gap:1rem}
.unit-ico{font-size:2.4rem}
.unit-kicker{color:var(--uc);font-weight:700;font-size:.8rem;text-transform:uppercase;letter-spacing:.06em}
.unit-title h1{font-size:1.8rem;letter-spacing:-.02em;line-height:1.15}
.unit-intro{color:var(--text-dim);margin:.9rem 0 1.2rem;max-width:50rem}
.unit-duration{font-size:.85rem;color:var(--text-muted);margin-bottom:1rem}

.tabs{display:flex;gap:.3rem;flex-wrap:wrap}
.tab{
  padding:.7rem 1.1rem;border-radius:10px 10px 0 0;font-weight:600;font-size:.92rem;
  color:var(--text-dim);border-bottom:2px solid transparent;
}
.tab:hover{color:var(--text);background:var(--hover)}
.tab.active{color:var(--uc,var(--accent));border-bottom-color:var(--uc,var(--accent));background:var(--accent-soft)}

.tabpanel{display:none;animation:fade .3s var(--ease)}
.tabpanel.active{display:block}
@keyframes fade{from{opacity:0;transform:translateY(6px)}to{opacity:1;transform:none}}

.unit-nav{display:flex;justify-content:space-between;gap:1rem;margin-top:2.5rem;padding-top:1.5rem;border-top:1px solid var(--border)}
.unav{padding:.8rem 1rem;border-radius:11px;background:var(--bg-card);border:1px solid var(--border);color:var(--text-dim);font-weight:600;font-size:.9rem;max-width:48%}
.unav:hover{color:var(--accent);border-color:var(--accent)}
.unav.next{margin-left:auto;text-align:right}

/* ─── Teoria: acordió + prosa ────────────────────────────────────────────── */
.accordion-item{border:1px solid var(--border);border-radius:12px;margin-bottom:.7rem;overflow:hidden;background:var(--bg-card)}
.accordion-head{
  width:100%;display:flex;justify-content:space-between;align-items:center;gap:1rem;
  padding:1rem 1.2rem;font-weight:600;font-size:1.02rem;text-align:left;
}
.accordion-head:hover{background:var(--hover)}
.acc-arrow{transition:.25s var(--ease);color:var(--text-dim)}
.accordion-item.open .acc-arrow{transform:rotate(180deg)}
.accordion-body{display:none;padding:0 1.2rem 1.3rem}
.accordion-item.open .accordion-body{display:block}
.prose{color:var(--text);font-size:.96rem}
.prose p{margin:.7rem 0}
.prose h4{margin:1.1rem 0 .4rem;font-size:1.05rem}
.prose h5{margin:.9rem 0 .3rem;font-size:.98rem;color:var(--text-dim)}
.prose ul,.prose ol{margin:.6rem 0 .6rem 1.3rem}
.prose li{margin:.25rem 0}
.prose code,code{font-family:var(--mono);font-size:.86em;background:var(--code-bg);padding:.12em .4em;border-radius:5px;color:var(--code-fg)}
.prose em{color:var(--text-dim)}

.callout{margin:1rem 0;padding:.8rem 1rem;border-radius:10px;font-size:.9rem;border-left:3px solid}
.callout p{margin:0 0 .5rem}
.callout p:last-child{margin-bottom:0}
.callout .code-block{margin:.6rem 0 0}
.callout.tip{background:var(--tip-bg);border-color:var(--accent)}
.callout.warn{background:var(--warn-bg);border-color:#f59e0b}
.callout.info{background:var(--info-bg);border-color:var(--accent2)}
.callout.note{background:var(--hover);border-color:var(--border)}

/* Bloc de codi (mostrar, no editar) */
.code-block{
  margin:1rem 0;border-radius:10px;overflow-x:auto;border:1px solid var(--code-border);
  background:var(--code-block-bg);color:var(--code-block-fg);
}
.code-block code{
  display:block;font-family:var(--mono);font-size:.86rem;padding:.9rem 1rem;line-height:1.65;
  background:none;color:inherit;border-radius:0;
}
/* Ressaltat de sintaxi Python lleuger (afegit per js/codeHighlight.js) */
.tok-kw{color:#ff7ab6;font-weight:600}
.tok-str{color:#a3e635}
.tok-com{color:#64748b;font-style:italic}
.tok-num{color:#f2c94c}
.tok-fn{color:#8fd3ff}

/* Taules */
.prose img{max-width:100%;height:auto;display:block;margin:.9rem auto;border-radius:10px;border:1px solid var(--border);box-shadow:0 2px 10px rgba(0,0,0,.15)}
.table-wrap{overflow-x:auto;margin:1rem 0}
.prose table{width:100%;border-collapse:collapse;font-size:.88rem}
.prose th,.prose td{text-align:left;padding:.55rem .7rem;border-bottom:1px solid var(--border)}
.prose th{color:var(--text-dim);font-weight:600;font-size:.8rem}

/* ─── Exercicis ──────────────────────────────────────────────────────────── */
.ex-legend{color:var(--text-dim);font-size:.9rem;margin-bottom:1.2rem}
.exercises{display:grid;gap:.8rem}
.exercise{background:var(--bg-card);border:1px solid var(--border);border-radius:12px;padding:1.1rem 1.3rem}
.exercise-head{display:flex;align-items:center;gap:.7rem;margin-bottom:.5rem}
.ex-level{font-size:.9rem;padding:.2rem .5rem;border-radius:999px;background:var(--bg-card);border:1px solid var(--border)}
.exercise h3{font-size:1rem}
.exercise .prose{font-size:.9rem}
.delivery-note{margin-top:1.5rem;padding:1.1rem 1.3rem;background:var(--accent-soft);border-radius:12px;border:1px solid var(--border)}
.delivery-note h4{margin-bottom:.5rem;color:var(--accent)}

.aules-link{
  display:inline-flex;align-items:center;gap:.5rem;margin-top:1.2rem;
  padding:.7rem 1.1rem;border-radius:11px;background:var(--bg-card);
  border:1px solid var(--border);font-weight:600;font-size:.88rem;color:var(--text-dim);
}
.aules-link:hover{color:var(--accent);border-color:var(--accent)}

/* ─── Animació conceptual inline (dins de cada secció de l'acordió) ──────── */
.concept-anim-inline{
  background:var(--bg-elev);border:1px solid var(--border);border-radius:var(--radius);
  padding:1.1rem;margin-top:1.1rem;
}
.concept-anim-label{font-size:.85rem;color:var(--text-dim);margin-bottom:.7rem;display:flex;align-items:center;gap:.5rem}
.anim-divider{border:none;border-top:1px dashed var(--border);margin:1.2rem 0}

/* ─── Instal·lació: pestanyes SO ─────────────────────────────────────────── */
.os-tabs{display:flex;gap:.5rem;margin-bottom:1.4rem;flex-wrap:wrap}
.os-tab{
  padding:.7rem 1.2rem;border-radius:11px;font-weight:600;font-size:.95rem;
  background:var(--bg-card);border:1px solid var(--border);color:var(--text-dim);
}
.os-tab:hover{color:var(--text)}
.os-tab.active{color:var(--accent);border-color:var(--accent);background:var(--accent-soft)}
.os-panel{display:none}
.os-panel.active{display:block;animation:fade .3s var(--ease)}

/* ─── Peu ────────────────────────────────────────────────────────────────── */
.site-footer{border-top:1px solid var(--border);padding:2rem 1.25rem;text-align:center;color:var(--text-dim);font-size:.85rem}
.site-footer strong{color:var(--text)}
.foot-dim{color:var(--text-muted);font-size:.78rem;margin-top:.5rem}

/* ─── Responsive ─────────────────────────────────────────────────────────── */
@media(max-width:820px){
  .hero{grid-template-columns:1fr;gap:1.5rem}
  .hero h1{font-size:2.1rem}
  .home-help{grid-template-columns:1fr}
  .hamburger{display:flex}
  .mainnav{
    position:fixed;top:56px;right:0;left:0;flex-direction:column;align-items:stretch;
    background:var(--bg-bar);border-bottom:1px solid var(--border);
    padding:.8rem 1.25rem 1.2rem;gap:.2rem;
    transform:translateY(-120%);transition:.3s var(--ease);
  }
  .mainnav.open{transform:translateY(0)}
}

/* Botó generat a partir de l'enllaç "Ara fes els exercicis" dels apunts. */
.anar-exercicis {
  font: inherit;
  color: var(--accent, #2563eb);
  background: none;
  border: none;
  border-bottom: 1px solid currentColor;
  padding: 0;
  cursor: pointer;
}
.anar-exercicis:hover { opacity: .75; }

.help-card p + p{margin-top:.6rem}

/* ─── Progrés personal (casella «Fet») ───────────────────────────────────── *
 * Portat del Taller de Python. NO és gamificació: ni punts, ni insígnies, ni
 * ratxes. L'entrega i la nota van per Aules. */
.uc-bar{height:4px;border-radius:999px;background:var(--hover);margin-top:.55rem;overflow:hidden}
.uc-bar i{display:block;height:100%;background:var(--uc,var(--accent));transition:width .4s var(--ease)}
.unitcard.completa{border-color:var(--uc,var(--accent))}
.unitcard.completa .unitcard-meta span::after{content:" ✓";color:var(--uc,var(--accent));font-weight:700}
.tri-compte{
  font:700 .78rem var(--mono);color:var(--text-dim);
  background:var(--hover);border-radius:999px;padding:.15rem .6rem;
}
.unit-progres{display:flex;align-items:center;gap:.9rem;margin:0 0 1rem;max-width:34rem}
.unit-progres .up-text{font-weight:600;font-size:.82rem;color:var(--text-dim);flex:none}
.unit-progres .up-bar{flex:1;height:6px;border-radius:999px;background:var(--hover);overflow:hidden}
.unit-progres .up-bar i{display:block;height:100%;width:0;background:var(--uc,var(--accent));transition:width .4s var(--ease)}
.unit-progres.completa .up-text{color:var(--uc,var(--accent))}
.ex-fet{
  margin-left:auto;display:inline-flex;align-items:center;gap:.45rem;flex:none;
  font-weight:600;font-size:.82rem;color:var(--text-dim);
  cursor:pointer;user-select:none;min-height:36px;
  padding:.3rem .65rem;border-radius:999px;border:1px solid var(--border);
}
.ex-fet:hover{color:var(--text);border-color:var(--accent)}
.ex-fet input{width:18px;height:18px;accent-color:var(--accent);cursor:pointer;margin:0}
.exercise.fet{border-color:var(--accent)}
.exercise.fet .ex-fet{color:var(--accent);border-color:var(--accent);background:var(--accent-soft)}
.exercise.fet .exercise-head h3{text-decoration:line-through;text-decoration-color:var(--text-muted)}
.btn-continua{flex-direction:column;align-items:flex-start;gap:.1rem;line-height:1.3;text-align:left}
.btn-continua .bc-dalt{font-size:.76rem;font-weight:600;opacity:.85}
.btn-continua .bc-baix{font-size:.98rem;font-weight:700}
.nota-progres{
  margin:2rem 0 0;padding:.9rem 1.1rem;border-radius:10px;
  background:var(--hover);color:var(--text-dim);
  font-size:.85rem;line-height:1.6;max-width:64ch;
}
.lnk-esborra{
  display:inline;margin-left:.4rem;padding:0;
  font:inherit;font-weight:600;color:var(--accent);
  background:none;border:0;border-bottom:1px solid currentColor;cursor:pointer;
}
.lnk-esborra:hover{opacity:.75}

/* ─── Guia de cada exercici (2026-09-28) ─────────────────────────────────── *
 * Mateix patró que els PI (🎯 què lliurar, ✅ comprova-ho, 💡 pistes) més dos
 * blocs propis d'este mòdul: 🧠 la teoria que hi ha darrere (amb botons a
 * l'apartat dels apunts) i 🩺 si no funciona. */
.guia-cap{display:block;font-size:.8rem;font-weight:800;text-transform:uppercase;letter-spacing:.04em;margin-bottom:.35rem}
.guia-lliurar{margin:.9rem 0 0;padding:.7rem .9rem;border-radius:10px;background:var(--info-bg);border-left:3px solid var(--accent)}
.guia-lliurar .guia-cap{color:var(--accent)}
.guia-lliurar .prose p{margin:0 0 .4rem}
.guia-lliurar .prose p:last-child{margin-bottom:0}
.guia-teoria{margin:.8rem 0 0;padding:.7rem .9rem;border-radius:10px;background:var(--bg-elev);border:1px solid var(--border);border-left:3px solid var(--accent2)}
.guia-teoria .guia-cap{color:var(--text)}
.guia-teoria .prose > :first-child{margin-top:0}
.guia-teoria .prose > :last-child{margin-bottom:0}
.anar-teoria{
  display:inline-flex;align-items:center;gap:.4rem;margin:.15rem .4rem .15rem 0;
  padding:.45rem .8rem;min-height:40px;border-radius:9px;
  border:1px solid var(--accent);color:var(--accent);background:var(--bg-card);
  font-weight:600;font-size:.88rem;line-height:1.3;
}
.anar-teoria:hover{background:var(--accent-soft)}
.guia-comprova{margin-top:.8rem;padding:.7rem .9rem;border-radius:10px;background:var(--tip-bg);border:1px solid var(--border)}
.guia-comprova .guia-cap{color:var(--text-dim)}
.guia-comprova ul{list-style:none;margin:0;padding:0;display:grid;gap:.3rem}
.guia-comprova label{display:flex;gap:.55rem;align-items:flex-start;cursor:pointer;font-size:.93rem;min-height:32px}
.guia-comprova input{width:20px;height:20px;margin-top:.12rem;flex:none;accent-color:var(--accent)}
.guia-comprova input:checked + span{color:var(--text-dim);text-decoration:line-through}

/* Pistes: tres desplegables tancats i seqüencials (com al Taller i als PI). */
.pistes{margin-top:.9rem;padding-top:.7rem;border-top:1px dashed var(--border)}
.pistes-cap{font-size:.85rem;color:var(--text-dim);margin:0 0 .4rem}
.pista{border:1px solid var(--border);border-radius:9px;background:var(--bg-elev);margin:.35rem 0}
.pista summary{
  cursor:pointer;padding:.5rem .8rem;display:flex;align-items:center;gap:.5rem;
  font-size:.93rem;list-style:none;border-radius:9px;min-height:40px;
}
.pista summary::-webkit-details-marker{display:none}
.pista summary::before{content:'▸';color:var(--accent2);transition:transform .15s var(--ease)}
.pista summary:hover{background:var(--hover)}
.pista[open] > summary::before{transform:rotate(90deg)}
.pista-num{font-weight:700;color:var(--accent)}
.pista-titol{color:var(--text-dim)}
.pista-lock{display:none;margin-left:auto;font-size:.85rem}
.pista.bloquejada summary{cursor:not-allowed;opacity:.55}
.pista.bloquejada summary::before{content:'·'}
.pista.bloquejada .pista-lock{display:inline}
.pista.sacseja{animation:sacseja .35s}
@keyframes sacseja{25%{transform:translateX(-3px)}75%{transform:translateX(3px)}}
.pista > .prose{padding:.2rem .9rem .8rem;font-size:.93rem}
.pista > .prose .code-block{margin:.5rem 0 0}

/* 🩺 Si no funciona: tancat per defecte, però sense bloqueig. */
.guia-diagnosi{margin-top:.8rem;border:1px solid var(--border);border-radius:9px;background:var(--warn-bg)}
.guia-diagnosi > summary{
  cursor:pointer;list-style:none;display:flex;align-items:center;gap:.5rem;
  padding:.5rem .8rem;min-height:40px;font-weight:700;font-size:.93rem;border-radius:9px;
}
.guia-diagnosi > summary::-webkit-details-marker{display:none}
.guia-diagnosi > summary::after{content:'⌄';margin-left:auto;color:var(--text-dim);transition:transform .15s var(--ease)}
.guia-diagnosi[open] > summary::after{transform:rotate(180deg)}
.guia-diagnosi > summary:hover{background:var(--hover)}
.guia-diagnosi > .prose{padding:0 .9rem .7rem}
.guia-diagnosi .prose ul{margin-top:.2rem}

/* ─── Seccions plegables (2026-10-06) ─────────────────────────────────────── *
 * Cada exercici i cada activitat es pot plegar pel títol; marcar «Fet» la
 * plega. El títol és un botó dins del <h3> (patró d'acordió accessible). */
.ex-titol{flex:1;min-width:0}
.ex-plega{
  width:100%;display:flex;align-items:center;gap:.6rem;text-align:left;
  font:inherit;font-weight:700;color:inherit;min-height:40px;padding:.15rem 0;border-radius:6px;
}
.ex-plega:hover{color:var(--accent)}
.ex-plega:focus-visible{outline:2px solid var(--accent);outline-offset:3px}
.ex-fletxa{margin-left:auto;color:var(--text-dim);font-size:1.1rem;line-height:1;transition:transform .2s var(--ease)}
.exercise.plegat .ex-fletxa{transform:rotate(-90deg)}
.exercise.plegat .exercise-head{margin-bottom:0}
.exercise.fet .ex-plega > span:first-child{text-decoration:line-through;text-decoration-color:var(--text-muted)}
.ex-cos[hidden]{display:none}
.plega-barra{display:flex;justify-content:flex-end;gap:.5rem;margin:0 0 .8rem}
.plega-btn{
  padding:.4rem .8rem;min-height:36px;border-radius:9px;font-size:.84rem;font-weight:600;
  border:1px solid var(--border);background:var(--bg-card);color:var(--text-dim);
}
.plega-btn:hover{color:var(--accent);border-color:var(--accent)}

/* Activitats de classe: agrupades per blocs */
.act-grup{margin-bottom:1.8rem}
.act-grup-titol{
  font-size:1.1rem;font-weight:700;color:var(--text-dim);margin:.4rem 0 .8rem;
  display:flex;align-items:center;gap:.6rem;
}
.act-grup-titol::after{content:"";flex:1;height:1px;background:var(--border)}

/* Saltar a la teoria i tornar: on cau el salt, i el botó de tornada. */
.exercise,.accordion-item,.prose h4,.tabs{scroll-margin-top:84px}
.ressalta{animation:ressalta 1.8s var(--ease)}
@keyframes ressalta{0%,35%{box-shadow:0 0 0 3px var(--accent)}100%{box-shadow:0 0 0 3px transparent}}
.tornada{
  position:fixed;left:50%;bottom:1.1rem;transform:translateX(-50%);z-index:60;
  padding:.75rem 1.25rem;min-height:44px;border-radius:999px;
  background:var(--accent);color:#fff;font-weight:700;font-size:.95rem;
  box-shadow:0 10px 30px -8px rgba(0,0,0,.55);
}
.tornada[hidden]{display:none}
.tornada:hover{filter:brightness(1.08)}

@media (prefers-reduced-motion:reduce){
  .pista.sacseja{animation:none}
  .ressalta{animation:none;outline:3px solid var(--accent);outline-offset:2px}
}
@media(max-width:560px){
  .exercise{padding:1rem}
  .exercise-head{flex-wrap:wrap}
  .ex-fet{margin-left:0}
}