.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 0.6rem;
  padding: 0.85rem 1.6rem; border-radius: var(--radius);
  background: var(--gold); color: var(--bg);
  font-family: var(--font-mono); font-size: 0.74rem; font-weight: 600; letter-spacing: 0.2em; text-transform: uppercase;
  border: 1px solid var(--gold); white-space: nowrap;
}
.btn--ghost { background: transparent; color: var(--gold-light); border-color: var(--gold-line); }
.btn--small { padding: 0.6rem 1.1rem; font-size: 0.68rem; }

.badge {
  display: inline-flex; align-items: center; gap: 0.7rem; padding: 0.5rem 1rem;
  border: 1px solid var(--gold-line); border-radius: 999px; background: var(--surface);
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px);
  font-family: var(--font-mono); font-size: 0.7rem; letter-spacing: 0.2em; text-transform: uppercase; color: var(--gold-light);
}
.badge__dot { width: 6px; height: 6px; border-radius: 50%; background: var(--gold); box-shadow: 0 0 10px var(--gold); }

.form { display: flex; gap: 0.6rem; max-width: 34rem; margin-top: 2rem; }
.form__input {
  flex: 1; min-width: 0; padding: 0.9rem 1.1rem; border-radius: var(--radius);
  background: var(--surface-strong); border: 1px solid var(--gold-line); color: var(--cream);
}
.form__input::placeholder { color: var(--cream-faint); }
.form__input:focus { outline: none; border-color: var(--gold); box-shadow: var(--shadow-glow); }
.form__input.is-invalid { border-color: var(--red); }

.stat__num { display: block; font-family: var(--font-display); font-size: clamp(1.7rem, 3vw, 2.4rem); color: var(--gold-light); line-height: 1.1; }
.stat__label { font-family: var(--font-mono); font-size: 0.66rem; letter-spacing: 0.2em; text-transform: uppercase; color: var(--cream-faint); }

.card {
  background: var(--surface); border: 1px solid var(--gold-line); border-radius: var(--radius);
  backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px);
}
.topic { padding: 2rem 1.8rem; display: flex; flex-direction: column; gap: 0.9rem; }
.topic__icon { font-size: 1.6rem; color: var(--gold); line-height: 1; }
.topic__title { font-family: var(--font-display); font-size: 1.45rem; font-weight: 500; line-height: 1.2; }
.topic__text { color: var(--cream-dim); font-size: 0.98rem; }
.topic__meta { margin-top: auto; padding-top: 0.6rem; font-family: var(--font-mono); font-size: 0.66rem; letter-spacing: 0.2em; text-transform: uppercase; color: var(--gold); }

.pull { padding: 2.2rem; border-left: 2px solid var(--gold); background: var(--surface); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); }
.pull__quote { font-family: var(--font-display); font-style: italic; font-size: clamp(1.3rem, 2.2vw, 1.75rem); line-height: 1.4; }
.pull__cite { display: block; margin-top: 1.1rem; font-family: var(--font-mono); font-size: 0.68rem; letter-spacing: 0.2em; text-transform: uppercase; color: var(--gold); font-style: normal; }

.checklist { display: grid; gap: 0.9rem; margin-top: 1.6rem; }
.checklist li { display: flex; gap: 0.9rem; color: var(--cream-dim); }
.checklist li::before { content: '✦'; color: var(--gold); flex: none; }

.issues { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; border: 1px solid var(--gold-line); border-radius: var(--radius); background: var(--surface); backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); }
.issue { padding: 1.5rem 1.6rem; border-bottom: 1px solid var(--gold-line); border-right: 1px solid var(--gold-line); display: grid; gap: 0.35rem; }
.issue__num { font-family: var(--font-mono); font-size: 0.66rem; letter-spacing: 0.24em; color: var(--gold); }
.issue__title { font-family: var(--font-display); font-size: 1.2rem; line-height: 1.25; }
.issue__text { font-size: 0.9rem; color: var(--cream-faint); font-style: italic; }

.visual { aspect-ratio: 4 / 5; padding: 2rem; display: grid; place-content: center; text-align: center; gap: 1rem; background: radial-gradient(circle at 50% 30%, var(--violet-soft), var(--surface) 70%); }
.visual__glyph { font-size: clamp(3rem, 7vw, 5rem); color: var(--gold); line-height: 1; }
.visual__line { font-family: var(--font-display); font-style: italic; font-size: 1.3rem; color: var(--cream-dim); }
.formula { display: flex; justify-content: center; gap: 0.8rem; flex-wrap: wrap; font-family: var(--font-display); font-size: clamp(1.5rem, 3vw, 2.2rem); }
.formula span:nth-child(even) { color: var(--gold); }

.book-wrap { perspective: 1200px; display: grid; place-items: center; padding: 1rem; }
.book3d {
  position: relative; width: 210px; height: 300px; transform-style: preserve-3d; transform: rotateY(-28deg) rotateX(4deg);
  box-shadow: 30px 30px 60px rgba(0, 0, 0, 0.6);
}
.book3d__face { position: absolute; inset: 0; border-radius: 2px 4px 4px 2px; backface-visibility: hidden; }
.book3d__front {
  background: url('../assets/portada.jpg') center / cover, var(--bg-soft);
  transform: translateZ(18px); border: 1px solid var(--gold-line);
}
.book3d__front::after { content: ''; position: absolute; inset: 0; background: linear-gradient(110deg, rgba(0, 0, 0, 0.5), transparent 25%, rgba(244, 234, 213, 0.12) 60%, transparent); }
.book3d__spine { width: 36px; left: -18px; right: auto; background: linear-gradient(180deg, var(--violet), var(--bg) 60%, var(--red)); transform: rotateY(-90deg) translateZ(0); border-left: 1px solid var(--gold-line); }
.book3d__pages { width: 34px; left: auto; right: -17px; background: repeating-linear-gradient(90deg, var(--cream), var(--cream) 1px, #cdbf9f 2px); transform: rotateY(90deg); }
.book3d__back { background: var(--bg-soft); transform: translateZ(-18px); }

.perks { display: grid; gap: 0.7rem; margin: 1.4rem 0 0.4rem; color: var(--cream-dim); }
.perks li::before { content: '◈'; color: var(--gold); margin-right: 0.8rem; }

.quote { padding: 2rem; display: flex; flex-direction: column; gap: 1.4rem; }
.quote__text { font-family: var(--font-display); font-style: italic; font-size: 1.2rem; line-height: 1.5; }
.quote__by { display: flex; align-items: center; gap: 0.9rem; margin-top: auto; }
.quote__avatar { width: 42px; height: 42px; display: grid; place-items: center; border: 1px solid var(--gold); border-radius: 50%; font-family: var(--font-display); color: var(--gold-light); }
.quote__name { font-family: var(--font-mono); font-size: 0.68rem; letter-spacing: 0.18em; text-transform: uppercase; color: var(--cream-dim); }

.price { max-width: 30rem; margin-inline: auto; padding: 3rem 2.4rem; text-align: center; border-color: var(--gold); box-shadow: var(--shadow-glow); }
.price__tag { font-family: var(--font-display); font-size: clamp(3.6rem, 8vw, 5.4rem); color: var(--gold-light); line-height: 1; margin: 1rem 0 0.2rem; }
.price__tag sup { font-size: 0.4em; vertical-align: top; margin-right: 0.15em; color: var(--gold); }
.price__note { font-family: var(--font-mono); font-size: 0.68rem; letter-spacing: 0.2em; text-transform: uppercase; color: var(--cream-faint); }
.price .perks { text-align: left; margin: 1.8rem 0; }
.price .btn { width: 100%; }

.faq { max-width: 52rem; margin-inline: auto; border-top: 1px solid var(--gold-line); }
.faq__item { border-bottom: 1px solid var(--gold-line); }
.faq__q { width: 100%; display: flex; justify-content: space-between; align-items: center; gap: 1.5rem; padding: 1.5rem 0; text-align: left; font-family: var(--font-display); font-size: clamp(1.15rem, 2vw, 1.4rem); }
.faq__icon { color: var(--gold); font-size: 1.3rem; flex: none; }
.faq__a { max-height: 0; overflow: hidden; }
.faq__a p { padding-bottom: 1.5rem; color: var(--cream-dim); }

.footer__brand p { color: var(--cream-faint); font-size: 0.95rem; max-width: 22rem; margin-top: 1rem; }
.footer__title { font-family: var(--font-mono); font-size: 0.7rem; letter-spacing: 0.24em; text-transform: uppercase; color: var(--gold); margin-bottom: 1.2rem; }
.footer__list { display: grid; gap: 0.7rem; color: var(--cream-dim); font-size: 0.95rem; }

.toast {
  position: fixed; left: 50%; bottom: 2rem; z-index: 120; max-width: calc(100% - 2rem);
  padding: 1rem 1.6rem; background: var(--surface-strong); border: 1px solid var(--gold); border-radius: var(--radius);
  backdrop-filter: blur(12px); -webkit-backdrop-filter: blur(12px); box-shadow: var(--shadow-card), var(--shadow-glow);
  font-family: var(--font-mono); font-size: 0.78rem; letter-spacing: 0.08em; color: var(--gold-light);
  opacity: 0; pointer-events: none; transform: translate(-50%, 20px);
}

@media (max-width: 900px) {
  .issues { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 500px) {
  .form { flex-direction: column; }
  .issues { grid-template-columns: 1fr; }
  .book3d { width: 170px; height: 242px; }
}