/* =============================================================
   0. Variables — identidad visual de Synapsis (app de estudio seria)
   ============================================================= */
:root {
  --bg: #0f1720;
  --bg-soft: #161f2b;
  --cream: #f7f6f2;
  --ink: #10151c;
  --muted: #8a95a3;
  --accent: #3f8efc;       /* acento único de marca; cada materia tiene su propio color en la app */
  --accent-ink: #0b1220;
  --ok: #2fa86a;
  --err: #e05a5a;
  --border: rgba(255,255,255,0.10);

  --serif: "Fraunces", Georgia, serif;
  --sans: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;

  --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);
  --ease-bounce: cubic-bezier(0.34, 1.56, 0.64, 1);

  --radius: 14px;
  --gutter: clamp(1.25rem, 4vw, 2.5rem);
}

/* =============================================================
   1. Reset mínimo
   ============================================================= */
*, *::before, *::after { box-sizing: border-box; margin: 0; }
html { -webkit-text-size-adjust: 100%; tab-size: 2; scroll-behavior: smooth; }
body {
  font-family: var(--sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--cream);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: clip;
  overscroll-behavior-y: none;
}
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; }
h1, h2, h3, h4 { font-family: var(--serif); text-wrap: balance; line-height: 1.1; letter-spacing: -0.01em; font-weight: 600; }
ul, ol { list-style: none; padding: 0; }
[hidden] { display: none !important; }
::selection { background: var(--accent); color: var(--accent-ink); }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 4px;
}

.skip-link {
  position: fixed; top: -100px; left: 1rem;
  padding: .6rem 1rem; background: var(--cream); color: var(--ink);
  z-index: 9999; border-radius: 8px; font-weight: 500;
}
.skip-link:focus { top: 1rem; }

/* =============================================================
   2. Layout utilities
   ============================================================= */
.wrap { max-width: 1120px; margin-inline: auto; padding-inline: var(--gutter); }

.btn {
  display: inline-flex; align-items: center; justify-content: center;
  padding: .7rem 1.3rem; border-radius: 999px; font-weight: 600;
  transition: transform .2s var(--ease-out), background .2s var(--ease-out), opacity .2s var(--ease-out);
}
.btn--primary { background: var(--accent); color: var(--accent-ink); }
.btn--primary:hover { transform: translateY(-1px); opacity: .92; }
.btn--ghost { border: 1px solid var(--border); color: var(--cream); }
.btn--ghost:hover { background: rgba(255,255,255,0.06); }
.btn--lg { padding: .9rem 1.8rem; font-size: 1.05rem; }

/* =============================================================
   3. Header
   ============================================================= */
.site-header { position: sticky; top: 0; z-index: 50; backdrop-filter: blur(10px); background: rgba(15,23,32,0.75); border-bottom: 1px solid var(--border); }
.site-header__inner { display: flex; align-items: center; justify-content: space-between; padding-block: 1rem; }
.brand { display: flex; align-items: center; gap: .5rem; font-family: var(--serif); font-weight: 600; font-size: 1.15rem; }
.site-nav { display: flex; align-items: center; gap: 1.25rem; font-weight: 500; }

/* =============================================================
   4. Hero
   ============================================================= */
.hero { padding-block: clamp(3rem, 8vw, 7rem) clamp(2.5rem, 6vw, 5rem); }
.hero__inner { max-width: 760px; }
.eyebrow { color: var(--accent); font-weight: 600; font-size: .85rem; letter-spacing: .06em; text-transform: uppercase; margin-bottom: 1rem; }
.hero h1 { font-size: clamp(2rem, 5vw, 3.4rem); margin-bottom: 1.25rem; }
.hero__lead { color: var(--muted); font-size: 1.15rem; max-width: 60ch; margin-bottom: 2rem; }
.hero__cta { display: flex; gap: 1rem; flex-wrap: wrap; }
.hero__disponible { margin-top: 1.5rem; color: var(--ok); font-weight: 600; font-size: .95rem; }

/* =============================================================
   5. Flow (cómo funciona)
   ============================================================= */
.flow { padding-block: clamp(3rem, 7vw, 6rem); border-top: 1px solid var(--border); }
.flow h2 { font-size: clamp(1.6rem, 3vw, 2.2rem); margin-bottom: 2.5rem; }
.flow__steps { display: grid; gap: 1.5rem; grid-template-columns: 1fr; }
.flow__step { background: var(--bg-soft); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.5rem; }
.flow__num { display: inline-flex; align-items: center; justify-content: center; width: 2rem; height: 2rem; border-radius: 50%; background: var(--accent); color: var(--accent-ink); font-weight: 700; margin-bottom: .9rem; }
.flow__step h3 { font-size: 1.15rem; margin-bottom: .5rem; }
.flow__step p { color: var(--muted); font-size: .95rem; }

/* =============================================================
   6. Why
   ============================================================= */
.why { padding-block: clamp(3rem, 7vw, 6rem); border-top: 1px solid var(--border); }
.why__inner { display: grid; gap: 2.5rem; }
.why h2 { font-size: clamp(1.5rem, 3vw, 2rem); margin-bottom: 1rem; }
.why p { color: var(--muted); }
.why__list { display: grid; gap: .9rem; }
.why__list li { padding-left: 1.6rem; position: relative; }
.why__list li::before { content: "✓"; position: absolute; left: 0; color: var(--ok); font-weight: 700; }

/* =============================================================
   7. CTA final + footer
   ============================================================= */
.cta-final { padding-block: clamp(3rem, 7vw, 6rem); text-align: center; border-top: 1px solid var(--border); }
.cta-final h2 { font-size: clamp(1.6rem, 3vw, 2.2rem); margin-bottom: 1.5rem; }

.site-footer { border-top: 1px solid var(--border); padding-block: 2rem; color: var(--muted); font-size: .9rem; }
.site-footer__inner { display: flex; flex-wrap: wrap; gap: 1rem; align-items: center; justify-content: space-between; }
.site-footer nav { display: flex; gap: 1.25rem; }

/* =============================================================
   8. Responsive
   ============================================================= */
@media (max-width: 480px) {
  .site-nav .btn { display: none; }   /* en teléfono, el botón grande ya está en el hero */
}
@media (min-width: 720px) {
  .flow__steps { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 1024px) {
  .flow__steps { grid-template-columns: repeat(4, 1fr); }
  .why__inner { grid-template-columns: 1fr 1fr; align-items: start; }
}

/* =============================================================
   9. Reduced motion
   ============================================================= */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

/* =============================================================
   10. Formularios de cuenta (registro, login, cuenta)
   ============================================================= */
.auth-main { max-width: 440px; margin-inline: auto; padding-block: clamp(3rem, 8vw, 6rem); }
.auth-main h1 { font-size: clamp(1.6rem, 3vw, 2rem); margin-bottom: .5rem; }
.auth-main .app-lead { margin-bottom: 2rem; }

.campo { display: grid; gap: .4rem; margin-bottom: 1.1rem; }
.campo label { font-weight: 600; font-size: .9rem; }
.campo input {
  padding: .75rem .9rem; border-radius: 10px; border: 1px solid var(--border);
  background: var(--bg-soft); color: var(--cream); font: inherit;
}
.campo input:focus-visible { outline: 2px solid var(--accent); outline-offset: 1px; }

.form-error { color: var(--err); font-size: .9rem; margin-block: .5rem 1rem; min-height: 1.2em; }
.form-nota { color: var(--muted); font-size: .9rem; margin-top: 1.5rem; }
.form-nota a { color: var(--accent); font-weight: 600; }

/* =============================================================
   11. Cuenta / admin — tarjetas de resumen
   ============================================================= */
.resumen-grid { display: grid; gap: 1rem; grid-template-columns: 1fr; margin-block: 1.5rem 2rem; }
@media (min-width: 720px) { .resumen-grid { grid-template-columns: repeat(3, 1fr); } }
.resumen-card { background: var(--bg-soft); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.25rem; }
.resumen-card__num { font-family: var(--serif); font-size: 2rem; font-weight: 600; display: block; }
.resumen-card__label { color: var(--muted); font-size: .9rem; }

.tabla-simple { width: 100%; border-collapse: collapse; margin-block: 1rem 2rem; font-size: .95rem; }
.tabla-simple th, .tabla-simple td { text-align: left; padding: .6rem .8rem; border-bottom: 1px solid var(--border); }
.tabla-simple th { color: var(--muted); font-weight: 600; font-size: .85rem; text-transform: uppercase; letter-spacing: .03em; }

.zona-peligro { margin-top: 3rem; padding-top: 1.5rem; border-top: 1px solid var(--border); }
.zona-peligro h2 { font-size: 1.1rem; color: var(--err); margin-bottom: .5rem; }
.btn--peligro { border: 1px solid var(--err); color: var(--err); }
.btn--peligro:hover { background: color-mix(in srgb, var(--err) 14%, transparent); }