/* =============================================================================
   Interlearning AI — styles.css
   Arquetipo: gradiente reactivo al cursor. Negro casi puro + un acento neón.
   Tipografía: Space Grotesk (display) / Inter (texto) / JetBrains Mono (etiquetas)
   ============================================================================= */

/* =============================================================
   1. Tokens
   ============================================================= */
:root {
  --bg:      #08080B;
  --bg-2:    #0D0D12;
  --bg-3:    #12121A;
  --bg-card: #101017;

  --ink:     #FAFAFA;
  --ink-2:   #C9C9D4;
  --mute:    #90909F;
  --mute-2:  #62626F;

  --accent:  #00E5FF;
  --accent-d:#00A9BD;
  --accent-soft: rgba(0, 229, 255, .12);

  --g1: #7C3AED;   /* violeta */
  --g2: #2563EB;   /* azul */
  --g3: #06B6D4;   /* cian */
  --g4: #F0407F;   /* magenta */

  --ok:   #34D399;
  --warn: #FBBF24;
  --err:  #FB7185;

  --line:   rgba(250, 250, 250, .10);
  --line-2: rgba(250, 250, 250, .055);

  --display: "Space Grotesk", "Segoe UI", system-ui, sans-serif;
  --sans:    "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono:    "JetBrains Mono", ui-monospace, Consolas, monospace;

  --ease-out:   cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in:    cubic-bezier(0.7, 0, 0.84, 0);
  --ease-soft:  cubic-bezier(0.25, 0.46, 0.45, 0.94);

  --nav-h: 74px;
  --pad:   clamp(1.15rem, 5vw, 4rem);
  --maxw:  1220px;
  --r:     14px;
}

/* =============================================================
   2. Reset y base
   ============================================================= */
*, *::before, *::after { box-sizing: border-box; margin: 0; }

html {
  -webkit-text-size-adjust: 100%;
  tab-size: 2;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-h) + 16px);
  background: var(--bg);
}

body {
  background: var(--bg);
  color: var(--ink-2);
  font-family: var(--sans);
  font-weight: 300;
  font-size: clamp(.98rem, .3vw + .9rem, 1.06rem);
  line-height: 1.65;
  overflow-x: clip;
  overscroll-behavior-y: none;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

img, svg, video { display: block; max-width: 100%; }
img { height: auto; }
button { font: inherit; color: inherit; cursor: pointer; border: 0; background: none; }
a { color: inherit; text-decoration: none; }
p { text-wrap: pretty; }
ul { margin: 0; padding: 0; list-style: none; }
dl, dd, dt { margin: 0; }
s { text-decoration-thickness: 1px; }

h1, h2, h3, h4 {
  margin: 0;
  font-family: var(--display);
  font-weight: 600;
  color: var(--ink);
  line-height: 1.04;
  letter-spacing: -0.025em;
  text-wrap: balance;
}

::selection { background: var(--accent); color: #04040A; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 6px;
}

.skip-link {
  position: fixed; top: -120px; left: 1rem; z-index: 9999;
  padding: .65rem 1.1rem; border-radius: 10px;
  background: var(--ink); color: var(--bg); font-weight: 600;
  transition: top .25s var(--ease-out);
}
.skip-link:focus { top: 1rem; }

/* =============================================================
   3. Utilidades
   ============================================================= */
.wrap {
  width: 100%;
  max-width: var(--maxw);
  margin-inline: auto;
  padding-inline: var(--pad);
}

.section { padding-block: clamp(4.5rem, 11vw, 9rem); position: relative; }

.section-kicker {
  font-family: var(--mono);
  font-size: .72rem;
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--mute-2);
  margin-bottom: 1.4rem;
}

.h2 {
  font-size: clamp(1.9rem, 5.2vw, 3.5rem);
  margin-bottom: clamp(2rem, 4vw, 3.2rem);
}

.lead {
  font-size: clamp(1.02rem, .5vw + .9rem, 1.18rem);
  color: var(--ink-2);
  max-width: 56ch;
}

.br-desk { display: none; }
@media (min-width: 720px) { .br-desk { display: inline; } }

/* Textura de grano muy sutil */
.grain {
  position: fixed; inset: 0; z-index: 3; pointer-events: none;
  opacity: .028;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='3'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* Barra de progreso de lectura */
.progress {
  position: fixed; top: 0; left: 0; z-index: 60;
  height: 2px; width: 100%;
  transform: scaleX(0); transform-origin: 0 50%;
  background: linear-gradient(90deg, var(--g1), var(--g3), var(--accent));
}

/* =============================================================
   4. Reveals (IntersectionObserver)
   ============================================================= */
/* Se ocultan SOLO si hay JS (la clase .js la pone un script en el head).
   Sin JS el contenido se ve tal cual: nunca una página en blanco. */
.js [data-reveal] {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity .85s var(--ease-out), transform .85s var(--ease-out);
}
.js [data-reveal].is-revealed { opacity: 1; transform: none; }

/* =============================================================
   5. Botones
   ============================================================= */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: .55rem;
  padding: .85rem 1.6rem;
  border-radius: 999px;
  background: var(--ink);
  color: #06060B;
  font-family: var(--sans);
  font-weight: 600;
  font-size: .93rem;
  letter-spacing: -.005em;
  border: 1px solid transparent;
  transition: transform .35s var(--ease-out), background .35s var(--ease-out),
              color .35s var(--ease-out), box-shadow .35s var(--ease-out);
}
.btn:hover {
  transform: translateY(-2px);
  background: var(--accent);
  box-shadow: 0 12px 34px -14px var(--accent);
}
.btn:active { transform: translateY(0); }

.btn-ghost {
  background: transparent;
  color: var(--ink);
  border-color: var(--line);
}
.btn-ghost:hover {
  background: rgba(250, 250, 250, .06);
  color: var(--ink);
  border-color: var(--accent);
  box-shadow: none;
}

.btn-lg { padding: 1.02rem 2rem; font-size: 1rem; }
.btn-sm { padding: .6rem 1.15rem; font-size: .84rem; }
.btn-full { width: 100%; }
.btn[disabled] { opacity: .5; pointer-events: none; }

/* =============================================================
   6. Splash
   ============================================================= */
.splash { display: none; }   /* sin JS no hay pantalla de carga */
.js .splash {
  position: fixed; inset: 0; z-index: 200;
  display: grid; place-content: center; gap: 1.4rem; justify-items: center;
  background: var(--bg);
  transition: opacity .7s var(--ease-out), visibility .7s;
  /* Seguridad: se oculta sola a los 4,5 s aunque falle el JS */
  animation: splashSafety .01s 4.5s forwards;
}
@keyframes splashSafety { to { opacity: 0; visibility: hidden; pointer-events: none; } }

.splash.is-out { opacity: 0; visibility: hidden; pointer-events: none; }

.splash-mark {
  font-family: var(--display);
  font-weight: 700;
  font-size: clamp(1.5rem, 6vw, 2.4rem);
  letter-spacing: -.04em;
  color: var(--ink);
}
.splash-mark span { color: var(--accent); }
.splash-mark i { font-style: normal; color: var(--mute-2); margin-left: .3em; }

.splash-bar { width: min(190px, 42vw); height: 2px; background: var(--line); overflow: hidden; }
.splash-bar span {
  display: block; height: 100%; width: 40%;
  background: linear-gradient(90deg, var(--g1), var(--accent));
  animation: splashRun 1.25s var(--ease-soft) infinite;
}
@keyframes splashRun {
  0%   { transform: translateX(-110%); }
  100% { transform: translateX(360%); }
}

/* =============================================================
   7. Navegación
   ============================================================= */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 90;
  height: var(--nav-h);
  display: flex; align-items: center; gap: 1.5rem;
  padding-inline: var(--pad);
  transition: background .4s var(--ease-out), border-color .4s var(--ease-out),
              backdrop-filter .4s var(--ease-out);
  border-bottom: 1px solid transparent;
}
.nav.is-stuck {
  background: rgba(8, 8, 11, .82);
  border-bottom-color: var(--line-2);
  backdrop-filter: blur(16px) saturate(140%);
}
@supports not (backdrop-filter: blur(4px)) {
  .nav.is-stuck { background: rgba(8, 8, 11, .97); }
}

.nav-brand {
  font-family: var(--display);
  font-weight: 700;
  font-size: 1.06rem;
  letter-spacing: -.035em;
  color: var(--ink);
  margin-right: auto;
}
.nav-brand-mark { color: var(--accent); }
.nav-brand i { font-style: normal; color: var(--mute-2); margin-left: .28em; font-size: .8em; }

.nav-links { display: none; gap: 1.9rem; }
.nav-links a {
  position: relative;
  font-size: .89rem;
  color: var(--mute);
  transition: color .3s var(--ease-out);
}
.nav-links a::after {
  content: ""; position: absolute; left: 0; bottom: -6px;
  width: 100%; height: 1px; background: var(--accent);
  transform: scaleX(0); transform-origin: 100% 50%;
  transition: transform .45s var(--ease-out);
}
.nav-links a:hover { color: var(--ink); }
.nav-links a:hover::after { transform: scaleX(1); transform-origin: 0 50%; }

.nav-cta { display: none; }

.nav-toggle {
  width: 44px; height: 44px; margin-right: -10px;
  display: grid; place-content: center; gap: 6px;
}
.nav-toggle span {
  display: block; width: 22px; height: 1.5px; background: var(--ink);
  transition: transform .4s var(--ease-out), opacity .3s;
}
.nav-toggle[aria-expanded="true"] span:first-child { transform: translateY(3.75px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:last-child  { transform: translateY(-3.75px) rotate(-45deg); }

@media (min-width: 960px) {
  .nav-links { display: flex; }
  .nav-cta { display: inline-flex; }
  .nav-toggle { display: none; }
}

/* Menú móvil */
.menu {
  position: fixed; inset: 0; z-index: 80;
  display: flex; flex-direction: column; justify-content: center; gap: 2rem;
  padding: var(--pad);
  background: var(--bg-2);
  opacity: 0; visibility: hidden;
  transform: translateY(-12px);
  transition: opacity .45s var(--ease-out), transform .45s var(--ease-out), visibility .45s;
}
.menu.is-open { opacity: 1; visibility: visible; transform: none; }

.menu-list { display: grid; gap: .35rem; }
.menu-list a {
  display: flex; align-items: baseline; gap: 1rem;
  padding-block: .55rem;
  font-family: var(--display);
  font-size: clamp(1.7rem, 8vw, 2.4rem);
  font-weight: 500;
  letter-spacing: -.035em;
  color: var(--ink);
}
.menu-list i {
  font-family: var(--mono); font-style: normal;
  font-size: .68rem; color: var(--accent); letter-spacing: .1em;
}
.menu-cta { align-self: start; }
.menu-foot { font-family: var(--mono); font-size: .68rem; color: var(--mute-2); letter-spacing: .06em; }

@media (min-width: 960px) { .menu { display: none; } }

/* =============================================================
   8. Hero — gradiente reactivo al cursor
   ============================================================= */
.hero {
  position: relative;
  min-height: 100svh;
  display: flex; align-items: center;
  padding-top: calc(var(--nav-h) + 3rem);
  padding-bottom: 4rem;
  overflow: clip;
}

.hero-gradient {
  position: absolute; inset: -20%;
  z-index: 0;
  background:
    radial-gradient(circle 46vw at var(--mx, 52%) var(--my, 34%), var(--g1) 0%, transparent 58%),
    radial-gradient(circle 40vw at calc(var(--mx, 52%) + 16%) calc(var(--my, 34%) + 14%), var(--g2) 0%, transparent 60%),
    radial-gradient(circle 30vw at calc(var(--mx, 52%) - 18%) calc(var(--my, 34%) + 8%), var(--g3) 0%, transparent 62%),
    radial-gradient(circle 26vw at 82% 78%, var(--g4) 0%, transparent 64%);
  filter: blur(90px) saturate(135%);
  opacity: .34;
  transition: background .55s var(--ease-soft);
}

.hero-lines {
  position: absolute; inset: 0; z-index: 0; pointer-events: none;
  background-image:
    linear-gradient(to right, var(--line-2) 1px, transparent 1px),
    linear-gradient(to bottom, var(--line-2) 1px, transparent 1px);
  background-size: 84px 84px;
  mask-image: radial-gradient(ellipse 75% 62% at 50% 42%, #000 30%, transparent 78%);
  -webkit-mask-image: radial-gradient(ellipse 75% 62% at 50% 42%, #000 30%, transparent 78%);
}

.hero-inner { position: relative; z-index: 2; width: 100%; max-width: var(--maxw); margin-inline: auto; padding-inline: var(--pad); }

.kicker {
  display: inline-flex; align-items: center; gap: .6rem;
  padding: .42rem .95rem .42rem .75rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(250, 250, 250, .035);
  font-family: var(--mono);
  font-size: .7rem;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--ink-2);
  margin-bottom: 1.8rem;
}
.kicker .dot {
  width: 7px; height: 7px; border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 0 0 var(--accent-soft);
  animation: pulse 2.4s var(--ease-soft) infinite;
}
@keyframes pulse {
  0%   { box-shadow: 0 0 0 0 rgba(0, 229, 255, .5); }
  70%  { box-shadow: 0 0 0 9px rgba(0, 229, 255, 0); }
  100% { box-shadow: 0 0 0 0 rgba(0, 229, 255, 0); }
}

.hero-title {
  font-size: clamp(2.6rem, 9.2vw, 6.6rem);
  font-weight: 700;
  letter-spacing: -.045em;
  line-height: .98;
  margin-bottom: 1.7rem;
}
.hero-title em {
  font-style: normal;
  background: linear-gradient(100deg, var(--accent) 0%, var(--g1) 55%, var(--g4) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.hero-sub {
  max-width: 58ch;
  font-size: clamp(1rem, .55vw + .88rem, 1.16rem);
  color: var(--ink-2);
  margin-bottom: 2.3rem;
}
.hero-sub em { color: var(--ink); font-style: italic; }

.hero-actions { display: flex; flex-wrap: wrap; gap: .8rem; margin-bottom: 1.5rem; }

.hero-note {
  font-family: var(--mono);
  font-size: .72rem;
  letter-spacing: .04em;
  color: var(--mute-2);
}

.hero-scroll {
  position: absolute; left: 50%; bottom: 26px; z-index: 2;
  translate: -50% 0;
  width: 1px; height: 54px;
  background: var(--line);
  overflow: hidden;
}
.hero-scroll span {
  display: block; width: 100%; height: 40%;
  background: var(--accent);
  animation: scrollRun 2.2s var(--ease-soft) infinite;
}
@keyframes scrollRun {
  0%   { transform: translateY(-100%); }
  100% { transform: translateY(260%); }
}

/* =============================================================
   9. Cifras
   ============================================================= */
.stats {
  border-block: 1px solid var(--line-2);
  background: var(--bg-2);
  padding-block: clamp(2.4rem, 5vw, 3.6rem);
}
.stats-grid {
  display: grid;
  gap: 2rem 1.5rem;
  grid-template-columns: repeat(2, 1fr);
}
@media (min-width: 960px) { .stats-grid { grid-template-columns: repeat(4, 1fr); } }

.stat span {
  display: block;
  font-size: .85rem;
  color: var(--mute);
  max-width: 26ch;
}
.stat-num {
  display: block;
  font-family: var(--display);
  font-weight: 600;
  font-size: clamp(1.9rem, 4.4vw, 2.9rem);
  letter-spacing: -.04em;
  color: var(--ink);
  margin-bottom: .35rem;
  font-variant-numeric: tabular-nums;
}

/* =============================================================
   10. Problema — manifiesto + filas
   ============================================================= */
.manifiesto {
  font-size: clamp(1.55rem, 4.2vw, 2.85rem);
  font-weight: 500;
  line-height: 1.16;
  letter-spacing: -.03em;
  max-width: 24ch;
  color: var(--ink);
  margin-bottom: clamp(2.8rem, 6vw, 4.5rem);
}
.manifiesto em { font-style: italic; color: var(--accent); }

.rows { border-top: 1px solid var(--line-2); }

.row-item {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1rem 1.4rem;
  padding-block: 1.7rem;
  border-bottom: 1px solid var(--line-2);
  transition: background .4s var(--ease-out);
}
.row-item:hover { background: rgba(250, 250, 250, .022); }

.row-idx {
  font-family: var(--mono);
  font-size: .7rem;
  letter-spacing: .1em;
  color: var(--accent);
  padding-top: .45rem;
}
.row-body h3 { font-size: clamp(1.06rem, 1.6vw, 1.28rem); font-weight: 500; margin-bottom: .5rem; }
.row-body p { color: var(--mute); max-width: 62ch; font-size: .95rem; }

@media (min-width: 720px) {
  .row-item { grid-template-columns: 60px 1fr; align-items: start; }
}

/* =============================================================
   11. Cómo funciona
   ============================================================= */
.como { background: var(--bg-2); border-block: 1px solid var(--line-2); }

.pasos {
  display: grid;
  gap: 1px;
  background: var(--line-2);
  border: 1px solid var(--line-2);
  border-radius: var(--r);
  overflow: hidden;
}
@media (min-width: 960px) { .pasos { grid-template-columns: repeat(3, 1fr); } }

.paso {
  background: var(--bg-2);
  padding: clamp(1.6rem, 3vw, 2.4rem);
  transition: background .45s var(--ease-out);
}
.paso:hover { background: var(--bg-3); }
.paso-num {
  display: block;
  font-family: var(--mono);
  font-size: .7rem;
  letter-spacing: .12em;
  color: var(--accent);
  margin-bottom: 1.4rem;
}
.paso h3 { font-size: 1.24rem; font-weight: 500; margin-bottom: .7rem; }
.paso p { color: var(--mute); font-size: .95rem; }
.paso em { color: var(--ink-2); font-style: italic; }

.como-nota {
  margin-top: 1.6rem;
  padding: 1.15rem 1.4rem;
  border: 1px solid var(--line);
  border-left: 2px solid var(--accent);
  border-radius: 0 var(--r) var(--r) 0;
  background: rgba(0, 229, 255, .035);
}
.como-nota p { font-size: .93rem; color: var(--ink-2); }
.como-nota strong { color: var(--ink); font-weight: 600; }

/* =============================================================
   12. Funcionalidades — lista acordeón
   ============================================================= */
.filtros { display: flex; flex-wrap: wrap; gap: .5rem; margin-bottom: 2rem; }

.chip {
  display: inline-flex; align-items: center; gap: .5rem;
  padding: .48rem 1rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  font-size: .82rem;
  color: var(--mute);
  transition: color .3s var(--ease-out), border-color .3s var(--ease-out),
              background .3s var(--ease-out);
}
.chip i {
  font-family: var(--mono); font-style: normal;
  font-size: .66rem; color: var(--mute-2);
}
.chip:hover { color: var(--ink); border-color: var(--line); background: rgba(250,250,250,.04); }
.chip.is-on {
  color: #06060B; background: var(--ink); border-color: var(--ink); font-weight: 500;
}
.chip.is-on i { color: rgba(6, 6, 11, .55); }

.func-list { border-top: 1px solid var(--line-2); }

.func { border-bottom: 1px solid var(--line-2); }
.func[hidden] { display: none; }

.func-head {
  width: 100%;
  display: grid;
  grid-template-columns: auto 1fr auto auto;
  align-items: center;
  gap: .9rem;
  padding: 1.35rem 0;
  text-align: left;
  transition: opacity .3s var(--ease-out);
}
.func-head:hover .func-name { color: var(--accent); }

.func-idx {
  font-family: var(--mono);
  font-size: .7rem;
  letter-spacing: .1em;
  color: var(--mute-2);
}
.func-name {
  font-family: var(--display);
  font-size: clamp(1rem, 1.9vw, 1.32rem);
  font-weight: 500;
  letter-spacing: -.02em;
  color: var(--ink);
  transition: color .35s var(--ease-out);
}

.func-tag {
  display: none;
  font-family: var(--mono);
  font-size: .62rem;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--mute-2);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: .22rem .6rem;
  white-space: nowrap;
}
.func-tag--alta { color: var(--accent); border-color: rgba(0, 229, 255, .35); }
@media (min-width: 720px) { .func-tag { display: inline-block; } }

.func-cross {
  position: relative;
  width: 15px; height: 15px;
  flex: none;
}
.func-cross::before,
.func-cross::after {
  content: ""; position: absolute; inset: 50% 0 auto 0;
  height: 1.5px; background: var(--ink);
  transition: transform .45s var(--ease-out), background .35s var(--ease-out);
}
.func-cross::after { transform: rotate(90deg); }
[aria-expanded="true"] .func-cross::before { background: var(--accent); }
[aria-expanded="true"] .func-cross::after  { transform: rotate(0deg); background: var(--accent); }

.func-body { padding: 0 0 1.8rem; }
.func-body[hidden] { display: none; }
.func-body > * { animation: fadeUp .5s var(--ease-out) both; }
@keyframes fadeUp { from { opacity: 0; transform: translateY(10px); } }

.func-desc {
  max-width: 68ch;
  color: var(--ink-2);
  font-size: .98rem;
  margin-bottom: 1.4rem;
}
.func-desc em { color: var(--ink); font-style: italic; }

.func-meta {
  display: grid;
  gap: 1px;
  background: var(--line-2);
  border: 1px solid var(--line-2);
  border-radius: var(--r);
  overflow: hidden;
}
@media (min-width: 720px)  { .func-meta { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1280px) { .func-meta { grid-template-columns: repeat(5, 1fr); } }

.func-meta > div { background: var(--bg-2); padding: 1rem 1.15rem; }
.func-meta dt {
  font-family: var(--mono);
  font-size: .62rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--mute-2);
  margin-bottom: .45rem;
}
.func-meta dd { font-size: .88rem; color: var(--ink-2); line-height: 1.5; }

.func-empty {
  padding-block: 2.5rem;
  text-align: center;
  color: var(--mute-2);
  font-family: var(--mono);
  font-size: .78rem;
}

/* =============================================================
   12b. Selector de idioma
   ============================================================= */
.lang {
  display: none;
  align-items: center;
  gap: .1rem;
  font-family: var(--mono);
  font-size: .7rem;
  letter-spacing: .08em;
}
.lang a,
.lang-on {
  padding: .3rem .45rem;
  border-radius: 6px;
  color: var(--mute-2);
  transition: color .3s var(--ease-out), background .3s var(--ease-out);
}
.lang a:hover { color: var(--ink); background: rgba(250, 250, 250, .06); }
.lang-on { color: var(--accent); }

@media (min-width: 960px) { .lang { display: flex; } }

.lang--menu {
  display: flex;
  font-size: .78rem;
  gap: .25rem;
  margin-top: -.5rem;
}
.lang--foot {
  display: flex;
  flex-wrap: wrap;
  font-size: .68rem;
  gap: .1rem .35rem;
}

/* =============================================================
   12c. Asignaturas — los seis grupos
   ============================================================= */
.materias { background: var(--bg-2); border-block: 1px solid var(--line-2); }

.leyenda {
  display: flex; flex-wrap: wrap; gap: .5rem 1.2rem;
  margin: 2rem 0 2.2rem;
}
.lg {
  display: inline-flex; align-items: center; gap: .5rem;
  font-family: var(--mono);
  font-size: .68rem;
  letter-spacing: .06em;
  color: var(--mute-2);
}
.lg::before {
  content: ""; width: 8px; height: 8px; border-radius: 2px;
  background: var(--line); border: 1px solid var(--line);
}
.lg--on::before   { background: var(--accent); border-color: var(--accent); }
.lg--next::before { background: transparent; border-color: var(--accent); }

.grupos { display: grid; gap: 1rem; }
@media (min-width: 720px)  { .grupos { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1280px) { .grupos { grid-template-columns: repeat(3, 1fr); } }

.grupo {
  display: flex; flex-direction: column;
  padding: clamp(1.4rem, 2.6vw, 1.8rem);
  border: 1px solid var(--line-2);
  border-radius: var(--r);
  background: var(--bg-card);
  transition: border-color .45s var(--ease-out);
}
.grupo:hover { border-color: var(--line); }
.grupo--on { border-color: rgba(0, 229, 255, .28); }
.grupo--core {
  border-color: var(--line);
  background: linear-gradient(180deg, rgba(124, 58, 237, .09), transparent 46%), var(--bg-card);
}

.grupo header { margin-bottom: 1.2rem; }
.grupo-num {
  display: block;
  font-family: var(--mono);
  font-size: .64rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: .5rem;
}
.grupo h3 { font-size: 1.1rem; font-weight: 500; }

.materia-list { display: grid; gap: .5rem; }
.materia-list li {
  display: flex; flex-wrap: wrap; align-items: baseline; gap: .45rem;
  padding-left: 1.15rem;
  position: relative;
  font-size: .89rem;
  color: var(--mute);
  line-height: 1.45;
}
.materia-list li::before {
  content: ""; position: absolute; left: 0; top: .52em;
  width: 7px; height: 7px; border-radius: 2px;
  background: var(--line);
}
.materia-list li.next { color: var(--ink-2); }
.materia-list li.next::before { background: transparent; box-shadow: inset 0 0 0 1px var(--accent); }
.materia-list li.on { color: var(--ink); }
.materia-list li.on::before { background: var(--accent); }

.materia-list i {
  font-family: var(--mono); font-style: normal;
  font-size: .62rem; letter-spacing: .06em;
  color: var(--mute-2);
}
.materia-list b {
  font-family: var(--mono); font-weight: 500;
  font-size: .58rem; letter-spacing: .1em; text-transform: uppercase;
  color: #04040A; background: var(--accent);
  border-radius: 999px; padding: .12rem .45rem;
}

.grupo-nota {
  margin-top: auto;
  padding-top: 1.1rem;
  font-size: .78rem;
  color: var(--mute-2);
  line-height: 1.45;
}

/* =============================================================
   13. Público
   ============================================================= */
.publico { background: var(--bg-2); border-block: 1px solid var(--line-2); }

.publico-grid { display: grid; gap: 1rem; }
@media (min-width: 720px)  { .publico-grid { grid-template-columns: repeat(2, 1fr); } }
@media (min-width: 1280px) { .publico-grid { grid-template-columns: repeat(4, 1fr); } }

.pub {
  position: relative;
  padding: clamp(1.5rem, 2.6vw, 1.9rem);
  border: 1px solid var(--line-2);
  border-radius: var(--r);
  background: var(--bg-card);
  overflow: hidden;
  transition: border-color .45s var(--ease-out), transform .45s var(--ease-out);
}
.pub::before {
  content: ""; position: absolute; inset: 0 0 auto 0; height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
  opacity: 0; transition: opacity .45s var(--ease-out);
}
.pub:hover { border-color: var(--line); transform: translateY(-3px); }
.pub:hover::before { opacity: 1; }

.pub-edad {
  font-family: var(--mono);
  font-size: .66rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: .8rem;
}
.pub h3 { font-size: 1.12rem; font-weight: 500; margin-bottom: .7rem; }
.pub p { font-size: .92rem; color: var(--mute); }
.pub-uso {
  margin-top: 1.1rem; padding-top: .9rem;
  border-top: 1px solid var(--line-2);
  font-size: .8rem !important;
  color: var(--mute-2) !important;
}

/* =============================================================
   14. Planes
   ============================================================= */
.promo-bar {
  display: flex; flex-wrap: wrap; align-items: center; gap: .8rem;
  padding: .85rem 1.15rem;
  border: 1px solid rgba(0, 229, 255, .28);
  border-radius: 999px;
  background: var(--accent-soft);
  margin-bottom: 1.8rem;
  font-size: .87rem;
  color: var(--ink-2);
}
.promo-flag {
  font-family: var(--mono);
  font-size: .64rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: #04040A;
  background: var(--accent);
  border-radius: 999px;
  padding: .28rem .7rem;
  white-space: nowrap;
}

.toggle {
  display: inline-flex;
  padding: 4px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--bg-2);
  margin-bottom: 2.2rem;
}
.toggle-btn {
  display: inline-flex; align-items: center; gap: .45rem;
  padding: .5rem 1.15rem;
  border-radius: 999px;
  font-size: .86rem;
  color: var(--mute);
  transition: background .35s var(--ease-out), color .35s var(--ease-out);
}
.toggle-btn i {
  font-family: var(--mono); font-style: normal; font-size: .64rem;
  color: var(--accent);
}
.toggle-btn.is-on { background: var(--ink); color: #06060B; font-weight: 500; }
.toggle-btn.is-on i { color: #06060B; }

.planes-grid { display: grid; gap: 1rem; align-items: start; }
@media (min-width: 1024px) { .planes-grid { grid-template-columns: repeat(3, 1fr); } }

.plan {
  position: relative;
  display: flex; flex-direction: column;
  padding: clamp(1.6rem, 3vw, 2.1rem);
  border: 1px solid var(--line-2);
  border-radius: 18px;
  background: var(--bg-card);
  transition: border-color .45s var(--ease-out);
}
.plan:hover { border-color: var(--line); }

.plan--destacado {
  border-color: rgba(0, 229, 255, .38);
  background:
    linear-gradient(180deg, rgba(0, 229, 255, .06), transparent 42%),
    var(--bg-card);
  box-shadow: 0 30px 80px -50px rgba(0, 229, 255, .6);
}
@media (min-width: 1024px) { .plan--destacado { transform: scale(1.022); } }

.plan-badge {
  position: absolute; top: -11px; left: clamp(1.6rem, 3vw, 2.1rem);
  font-family: var(--mono);
  font-size: .62rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: #04040A;
  background: var(--accent);
  border-radius: 999px;
  padding: .3rem .75rem;
}

.plan-head { margin-bottom: 1.3rem; }
.plan-head h3 { font-size: 1.3rem; font-weight: 600; margin-bottom: .35rem; }
.plan-desc { font-size: .88rem; color: var(--mute); }

.plan-precio {
  display: flex; align-items: baseline; flex-wrap: wrap; gap: .45rem;
  margin-bottom: .5rem;
}
.plan-cifra {
  font-family: var(--display);
  font-size: clamp(2.1rem, 4.6vw, 2.9rem);
  font-weight: 600;
  letter-spacing: -.04em;
  color: var(--ink);
  font-variant-numeric: tabular-nums;
}
.plan-antes { font-size: 1rem; color: var(--mute-2); }

/* El precio tachado es el mensual de lista. Junto a un precio anual comparado
   por mes no compara nada, así que en ciclo anual desaparece. */
html[data-ciclo="anual"] .plan-antes { display: none; }
.plan-desde,
.plan-ciclo { font-size: .88rem; color: var(--mute); }

.plan-facturacion {
  font-size: .8rem;
  color: var(--mute-2);
  margin-bottom: 1.5rem;
  min-height: 1.2em;
}

.plan-list {
  display: grid; gap: .68rem;
  margin-bottom: 1.8rem;
  padding-top: 1.4rem;
  border-top: 1px solid var(--line-2);
}
.plan-list li {
  position: relative;
  padding-left: 1.5rem;
  font-size: .9rem;
  color: var(--ink-2);
  line-height: 1.5;
}
.plan-list li::before {
  content: ""; position: absolute; left: 0; top: .48em;
  width: 8px; height: 8px;
  border-radius: 2px;
  background: var(--accent);
  opacity: .8;
}

.plan .btn { margin-top: auto; }
.plan-nota {
  margin-top: .9rem;
  font-size: .76rem;
  color: var(--mute-2);
  line-height: 1.45;
}

.planes-legal {
  margin-top: 1.8rem;
  font-size: .8rem;
  color: var(--mute-2);
  max-width: 70ch;
}

/* =============================================================
   15. Colegios + formulario
   ============================================================= */
.colegios { background: var(--bg-2); border-block: 1px solid var(--line-2); }

.colegios-inner { display: grid; gap: clamp(2.5rem, 5vw, 4rem); align-items: start; }
@media (min-width: 1024px) { .colegios-inner { grid-template-columns: 1fr .82fr; } }

.colegios-list { display: grid; gap: .9rem; margin-top: 2rem; }
.colegios-list li {
  padding-left: 1.4rem;
  position: relative;
  font-size: .92rem;
  color: var(--mute);
}
.colegios-list li::before {
  content: ""; position: absolute; left: 0; top: .62em;
  width: 6px; height: 1px; background: var(--accent);
}
.colegios-list strong { color: var(--ink); font-weight: 600; }

.form {
  padding: clamp(1.5rem, 3vw, 2.1rem);
  border: 1px solid var(--line-2);
  border-radius: 18px;
  background: var(--bg-card);
  display: grid;
  gap: 1rem;
}
.form-title {
  font-family: var(--display);
  font-size: 1.16rem;
  font-weight: 600;
  color: var(--ink);
}

.field { display: grid; gap: .4rem; }
.field > span {
  font-family: var(--mono);
  font-size: .66rem;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--mute-2);
}
.field > span i { font-style: normal; text-transform: none; letter-spacing: 0; }

.field input,
.field select,
.field textarea {
  width: 100%;
  padding: .78rem .9rem;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--bg-3);
  color: var(--ink);
  font: inherit;
  font-size: .92rem;
  transition: border-color .3s var(--ease-out), background .3s var(--ease-out);
}
.field textarea { resize: vertical; min-height: 84px; }
.field select { appearance: none; cursor: pointer; }
.field input::placeholder,
.field textarea::placeholder { color: var(--mute-2); }
.field input:focus,
.field select:focus,
.field textarea:focus {
  outline: none;
  border-color: var(--accent);
  background: var(--bg-2);
}
.field input[aria-invalid="true"],
.field select[aria-invalid="true"],
.field textarea[aria-invalid="true"] { border-color: var(--err); }

.field-row { display: grid; gap: 1rem; }
@media (min-width: 540px) { .field-row { grid-template-columns: 1fr 1fr; } }

.check {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: .7rem;
  align-items: start;
  font-size: .82rem;
  color: var(--mute);
  line-height: 1.5;
  cursor: pointer;
}
.check input {
  width: 17px; height: 17px;
  margin-top: .18rem;
  accent-color: var(--accent);
  cursor: pointer;
}
.check a { color: var(--ink-2); text-decoration: underline; text-underline-offset: 3px; }
.check a:hover { color: var(--accent); }
.check.is-invalid { color: var(--err); }

.form-msg {
  font-size: .84rem;
  min-height: 1.2em;
  color: var(--mute);
}
.form-msg.is-ok  { color: var(--ok); }
.form-msg.is-err { color: var(--err); }

/* =============================================================
   16. FAQ
   ============================================================= */
.faq-list { border-top: 1px solid var(--line-2); max-width: 900px; }
.qa { border-bottom: 1px solid var(--line-2); }

.qa-head {
  width: 100%;
  display: flex; align-items: center; justify-content: space-between; gap: 1.5rem;
  padding: 1.35rem 0;
  text-align: left;
  font-family: var(--display);
  font-size: clamp(1rem, 1.7vw, 1.16rem);
  font-weight: 500;
  letter-spacing: -.02em;
  color: var(--ink);
  transition: color .35s var(--ease-out);
}
.qa-head:hover { color: var(--accent); }

.qa-body { padding-bottom: 1.6rem; }
.qa-body[hidden] { display: none; }
.qa-body p {
  max-width: 72ch;
  font-size: .95rem;
  color: var(--mute);
  animation: fadeUp .5s var(--ease-out) both;
}
.qa-body em { color: var(--ink-2); font-style: italic; }

/* =============================================================
   17. Aviso de marca
   ============================================================= */
.aviso { padding-block: clamp(3rem, 6vw, 4.5rem); }
.aviso-inner {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1.2rem;
  padding: clamp(1.4rem, 3vw, 2rem);
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--bg-2);
}
.aviso-icon {
  display: grid; place-content: center;
  width: 32px; height: 32px;
  border-radius: 50%;
  border: 1px solid var(--warn);
  color: var(--warn);
  font-family: var(--display);
  font-weight: 700;
  font-size: 1rem;
}
.aviso-title {
  font-size: 1.06rem;
  font-weight: 600;
  margin-bottom: .7rem;
}
.aviso-inner p { font-size: .87rem; color: var(--mute); max-width: 92ch; }

/* =============================================================
   18. Contacto
   ============================================================= */
.contacto { padding-bottom: clamp(5rem, 10vw, 8rem); }
.contacto-inner { text-align: left; }

.contacto-mail {
  display: inline-block;
  position: relative;
  font-family: var(--display);
  font-size: clamp(1.5rem, 6.4vw, 4.2rem);
  font-weight: 600;
  letter-spacing: -.045em;
  color: var(--ink);
  line-height: 1.05;
  word-break: break-word;
  transition: color .4s var(--ease-out);
}
.contacto-mail::after {
  content: ""; position: absolute; left: 0; bottom: .04em;
  width: 100%; height: 2px;
  background: linear-gradient(90deg, var(--accent), var(--g1));
  transform: scaleX(0); transform-origin: 0 50%;
  transition: transform .6s var(--ease-out);
}
.contacto-mail:hover { color: var(--accent); }
.contacto-mail:hover::after { transform: scaleX(1); }

.contacto-sub {
  margin-top: 1.6rem;
  max-width: 54ch;
  color: var(--mute);
  font-size: .96rem;
}

/* =============================================================
   19. Footer
   ============================================================= */
.footer {
  border-top: 1px solid var(--line-2);
  background: var(--bg-2);
  padding-block: clamp(2.5rem, 5vw, 3.5rem) 1.6rem;
}
.footer-grid { display: grid; gap: 2rem; }
@media (min-width: 720px) { .footer-grid { grid-template-columns: 1.4fr 1fr 1fr; } }

.footer-brand {
  font-family: var(--display);
  font-weight: 700;
  font-size: 1.06rem;
  letter-spacing: -.035em;
  color: var(--ink);
  margin-bottom: .4rem;
}
.footer-brand i { font-style: normal; color: var(--mute-2); margin-left: .28em; font-size: .8em; }
.footer-tag { font-size: .86rem; color: var(--mute-2); }

.footer-links { display: grid; gap: .55rem; align-content: start; }
.footer-links a {
  font-size: .86rem;
  color: var(--mute);
  transition: color .3s var(--ease-out);
}
.footer-links a:hover { color: var(--accent); }

.footer-base {
  display: flex; flex-wrap: wrap; gap: .6rem 1.5rem;
  justify-content: space-between;
  margin-top: 2.5rem;
  padding-top: 1.4rem;
  border-top: 1px solid var(--line-2);
}
.footer-base p {
  font-family: var(--mono);
  font-size: .68rem;
  letter-spacing: .04em;
  color: var(--mute-2);
}

/* =============================================================
   20. Modal de checkout
   ============================================================= */
.modal {
  width: min(460px, calc(100vw - 2rem));
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--bg-2);
  color: var(--ink-2);
  overflow: visible;
}
.modal::backdrop { background: rgba(4, 4, 8, .78); backdrop-filter: blur(6px); }
.modal[open] { animation: modalIn .4s var(--ease-out) both; }
@keyframes modalIn { from { opacity: 0; transform: translateY(14px) scale(.985); } }

.modal-close {
  position: absolute; top: 10px; right: 14px;
  width: 34px; height: 34px;
  font-size: 1.6rem; line-height: 1;
  color: var(--mute);
  transition: color .3s var(--ease-out);
}
.modal-close:hover { color: var(--ink); }

.modal-body { padding: clamp(1.5rem, 4vw, 2rem); display: grid; gap: 1rem; }
.modal-body form { display: grid; gap: 1rem; }

.modal-kicker {
  font-family: var(--mono);
  font-size: .66rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--accent);
}
.modal-title { font-size: 1.4rem; font-weight: 600; }
.modal-precio {
  font-family: var(--mono);
  font-size: .84rem;
  color: var(--mute);
  padding-bottom: .4rem;
  border-bottom: 1px solid var(--line-2);
}

/* =============================================================
   21. Página legal
   ============================================================= */
.legal-hero { padding-top: calc(var(--nav-h) + clamp(3rem, 8vw, 6rem)); }
.legal-title { font-size: clamp(2rem, 6vw, 3.4rem); margin-bottom: 1rem; }
.legal-fecha {
  font-family: var(--mono); font-size: .72rem;
  letter-spacing: .08em; color: var(--mute-2);
}

.legal-doc { max-width: 76ch; }
.legal-doc h2 {
  font-size: clamp(1.3rem, 3vw, 1.7rem);
  margin-top: 3.2rem;
  margin-bottom: 1rem;
  padding-top: 2rem;
  border-top: 1px solid var(--line-2);
  scroll-margin-top: calc(var(--nav-h) + 20px);
}
.legal-doc h3 {
  font-size: 1.04rem;
  font-weight: 600;
  margin-top: 1.8rem;
  margin-bottom: .6rem;
}
.legal-doc p { margin-bottom: 1rem; color: var(--mute); font-size: .95rem; }
.legal-doc ul { display: grid; gap: .6rem; margin-bottom: 1.2rem; }
.legal-doc li {
  position: relative; padding-left: 1.3rem;
  color: var(--mute); font-size: .95rem;
}
.legal-doc li::before {
  content: ""; position: absolute; left: 0; top: .68em;
  width: 6px; height: 1px; background: var(--accent);
}
.legal-doc strong { color: var(--ink); font-weight: 600; }
.legal-doc a { color: var(--accent); text-decoration: underline; text-underline-offset: 3px; }

/* =============================================================
   22. Página de gracias
   ============================================================= */
.gracias {
  min-height: 100svh;
  display: grid; place-content: center; justify-items: start;
  padding: calc(var(--nav-h) + 3rem) var(--pad) 4rem;
  position: relative;
  overflow: clip;
}
.gracias-inner { max-width: 60ch; position: relative; z-index: 2; }
.gracias-title { font-size: clamp(2.2rem, 7vw, 4rem); margin-bottom: 1.3rem; }
.gracias p { color: var(--mute); margin-bottom: 1rem; }
.gracias-pasos {
  display: grid; gap: .8rem;
  margin: 2rem 0;
  padding: 1.3rem 1.5rem;
  border: 1px solid var(--line-2);
  border-radius: var(--r);
  background: var(--bg-2);
}
.gracias-pasos li {
  position: relative; padding-left: 1.9rem;
  font-size: .93rem; color: var(--ink-2);
}
.gracias-pasos li i {
  position: absolute; left: 0; top: .1em;
  font-family: var(--mono); font-style: normal;
  font-size: .7rem; color: var(--accent);
}

/* =============================================================
   23. Movimiento reducido — solo lo intrusivo
   ============================================================= */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .splash-bar span,
  .hero-scroll span,
  .kicker .dot { animation: none; }
}