/* Cuadernillo de reactivos · Polart. Conserva la base visual de tu aplicación. */
:root {
  color-scheme: dark;
  --fondo: #0a1931;
  --tarjeta: #102541;
  --borde: #34465d;
  --texto: #ffffff;
  --secundario: #bac7d8;
  --acento: #72c9ec;
}
* { box-sizing: border-box; }
html { -webkit-font-smoothing: antialiased; }
body { margin: 0; background: var(--fondo); color: var(--texto); font-family: Arial, sans-serif; }
a { color: inherit; }
button, input { font: inherit; }
button { cursor: pointer; }
[hidden] { display: none !important; }
:focus-visible { outline: 3px solid var(--acento); outline-offset: 5px; }
.saltar-contenido { position: fixed; top: -100px; left: 16px; z-index: 10; padding: 12px; background: #fff; color: #0a1931; }
.saltar-contenido:focus { top: 12px; }
.app-header { max-width: 1120px; margin: 0 auto; padding: 23px 24px; display: flex; justify-content: space-between; align-items: center; gap: 16px; border-bottom: 1px solid #ffffff20; }
.marca { font-size: 18px; font-weight: 700; letter-spacing: -.3px; text-decoration: none; }
.nivel { font-size: 13px; color: var(--secundario); }
.home-container { width: min(1120px, 100%); margin: 0 auto; padding: 44px 24px 40px; }
.eyebrow { margin: 0 0 10px; color: var(--secundario); font-size: 12px; letter-spacing: 1.2px; text-transform: uppercase; }
h1 { margin: 0; font-size: clamp(25px, 4vw, 34px); line-height: 1.2; letter-spacing: -.6px; }
.introduccion { margin: 13px 0 0; color: var(--secundario); font-size: 15px; line-height: 1.6; }
.course-section { margin-top: 36px; }
.section-heading { display: flex; justify-content: space-between; align-items: center; gap: 18px; margin-bottom: 18px; }
.course-title { margin: 0; font-size: 18px; font-weight: 700; }
.carousel-controls { display: flex; gap: 8px; }
.carousel-control { display: grid; place-items: center; width: 42px; height: 42px; border-radius: 8px; border: 1px solid var(--borde); background: transparent; color: white; font-size: 23px; }
.carousel-control:disabled { opacity: .3; cursor: default; }
.course-slider { display: flex; gap: 16px; overflow-x: auto; padding: 6px 4px 18px; margin: 0 -4px; scroll-snap-type: x mandatory; scroll-padding: 4px; -webkit-overflow-scrolling: touch; scrollbar-width: thin; scrollbar-color: #52657f transparent; }
.course { flex: 0 0 218px; min-height: 194px; padding: 22px; background: var(--tarjeta); border: 1px solid var(--borde); border-radius: 12px; text-decoration: none; scroll-snap-align: start; display: flex; flex-direction: column; align-items: flex-start; text-align: left; transition: background .15s, border-color .15s; }
.course:hover { background: #173350; border-color: #7e9cb6; }
.course-index { font-size: 12px; color: var(--secundario); }
.course-name { margin-top: 28px; font-size: 21px; line-height: 1.25; font-weight: 700; }
.course-meta { width: 100%; display: flex; justify-content: space-between; align-items: center; gap: 12px; color: var(--secundario); margin-top: auto; padding-top: 18px; font-size: 13px; }
.course-meta .flecha { color: white; font-size: 21px; }
.carousel-footer { display: flex; justify-content: space-between; gap: 16px; margin-top: 12px; color: var(--secundario); font-size: 12px; line-height: 1.5; }
.app-footer { margin-top: 50px; padding-top: 20px; border-top: 1px solid #ffffff20; color: var(--secundario); font-size: 12px; }
.back-link { display: inline-flex; align-items: center; gap: 8px; text-decoration: none; font-size: 14px; color: var(--secundario); }
.back-link:hover { color: white; }
@media (max-width: 600px) {
  .app-header { padding: 19px 20px; }
  .home-container { padding: 30px 20px; }
  .course { flex-basis: 68vw; max-width: 280px; min-height: 184px; }
  .course-section { margin-top: 28px; }
  .carousel-footer { flex-wrap: wrap; }
}
@media (prefers-reduced-motion: reduce) { * { scroll-behavior: auto !important; transition: none !important; } }

/* ═══ ÍNDICE · crema y tarjetas ligeras, siguiendo la referencia Hack en Línea ═══
   Este bloque se aplica solo al índice. Los estilos compartidos siguen arriba. */
html.indice-reactivos-html {
  color-scheme: light;
  background: #feffd7;
}
body.indice-reactivos {
  --fondo: #feffd7;
  --tarjeta: rgba(255, 255, 255, .38);
  --borde: rgba(17, 24, 39, .1);
  --texto: #111827;
  --secundario: rgba(17, 24, 39, .64);
  --acento: #111827;
  color-scheme: light;
  min-height: 100vh;
  min-height: 100svh;
  background: var(--fondo);
  color: var(--texto);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}
.indice-reactivos .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;
}
.indice-reactivos .app-header {
  max-width: 1280px;
  padding: 26px 32px;
  border: 0;
}
.indice-reactivos .marca {
  font-size: 17px;
  font-weight: 800;
  letter-spacing: -.55px;
}
.indice-reactivos .home-container {
  width: min(1280px, 100%);
  padding: 36px 32px 64px;
}
.indice-reactivos .indice-heading {
  max-width: 900px;
  margin: 0 auto;
  text-align: center;
}
.indice-reactivos h1 {
  font-size: clamp(32px, 4.8vw, 55px);
  font-weight: 850;
  line-height: 1.08;
  letter-spacing: -.065em;
}
.indice-reactivos .introduccion {
  margin-top: 18px;
  font-size: 16px;
  font-weight: 500;
  line-height: 1.6;
}
.indice-reactivos .course-section { margin-top: 38px; }
.indice-reactivos .course-slider {
  position: relative;
  gap: 22px;
  margin: 0 -12px;
  padding: 22px 12px 44px;
  overflow-x: auto;
  overflow-y: hidden;
  scroll-snap-type: none;
  scroll-behavior: auto;
  overscroll-behavior-x: contain;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
  cursor: grab;
  user-select: none;
  -webkit-user-select: none;
}
.indice-reactivos .course-slider::-webkit-scrollbar { display: none; }
.indice-reactivos .course-slider.is-dragging,
.indice-reactivos .course-slider.is-dragging .course { cursor: grabbing; }
.indice-reactivos .course {
  position: relative;
  isolation: isolate;
  flex: 0 0 330px;
  min-height: 285px;
  max-width: none;
  padding: 32px;
  display: grid;
  place-items: center;
  text-align: center;
  overflow: hidden;
  border: 2px solid var(--borde);
  border-radius: 28px;
  background: var(--tarjeta);
  box-shadow: 0 20px 44px rgba(0, 0, 0, .1);
  scroll-snap-align: none;
  transition: border-color 180ms ease, box-shadow 180ms ease, background 180ms ease;
  -webkit-tap-highlight-color: transparent;
  -webkit-user-drag: none;
}
.indice-reactivos .course::before,
.indice-reactivos .course::after {
  content: "";
  position: absolute;
  width: 190px;
  height: 190px;
  border: 1px solid rgba(17, 24, 39, .065);
  border-radius: 50%;
  pointer-events: none;
  z-index: -1;
}
.indice-reactivos .course::before { top: -105px; right: -60px; }
.indice-reactivos .course::after { top: -86px; right: -81px; }
.indice-reactivos .course-name {
  max-width: 250px;
  margin: 0;
  color: #111827;
  font-size: 29px;
  font-weight: 760;
  line-height: 1.2;
  letter-spacing: -.045em;
}
.indice-reactivos .course:focus-visible { outline-offset: -6px; }
.indice-reactivos .carousel-controls { justify-content: center; gap: 12px; }
.indice-reactivos .carousel-control {
  width: 46px;
  height: 46px;
  background: rgba(255, 255, 255, .25);
  color: #111827;
  border: 1px solid rgba(17, 24, 39, .16);
  border-radius: 50%;
  font-size: 21px;
  transition: background 150ms ease, opacity 150ms ease;
}
.indice-reactivos .carousel-control:disabled { opacity: .26; }
@media (hover: hover) {
  .indice-reactivos .course:hover {
    background: rgba(255, 255, 255, .55);
    border-color: rgba(17, 24, 39, .18);
    box-shadow: 0 23px 48px rgba(0, 0, 0, .12);
  }
  .indice-reactivos .carousel-control:hover:not(:disabled) { background: rgba(255, 255, 255, .6); }
}
@media (max-width: 600px) {
  .indice-reactivos .app-header { padding: 23px 22px; }
  .indice-reactivos .home-container { padding: 28px 22px 44px; }
  .indice-reactivos .indice-heading { max-width: 360px; }
  .indice-reactivos .introduccion { margin-top: 15px; font-size: 15px; }
  .indice-reactivos .course-section { margin-top: 27px; }
  .indice-reactivos .course-slider { gap: 18px; padding-bottom: 36px; }
  .indice-reactivos .course { flex-basis: 86%; min-height: 264px; padding: 28px 22px; border-radius: 26px; }
  .indice-reactivos .course-name { font-size: 27px; }
}