/* Purpose: Button component. Gold fill, ink text, light sweep on hover. */

.btn {
  --btn-ink: var(--color-ink);
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-3);
  padding: var(--space-5) var(--space-10);
  border: 0;
  border-radius: var(--radius-full);
  background: var(--gradient-gold-soft);
  color: var(--btn-ink);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: var(--weight-bold);
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
  line-height: 1.2;
  text-align: center;
  cursor: pointer;
  overflow: hidden;
  isolation: isolate;
  box-shadow: var(--glow-sm), var(--shadow-md);
  transition:
    transform var(--duration-base) var(--ease-spring),
    box-shadow var(--duration-base) var(--ease-out),
    color var(--duration-base) var(--ease-out);
}

/* Specular sweep across the metal. */
.btn::before {
  content: '';
  position: absolute;
  inset: 0;
  z-index: -1;
  background: linear-gradient(110deg, transparent 20%, rgba(255,255,255,0.65) 50%, transparent 80%);
  transform: translateX(-120%);
  transition: transform var(--duration-slower) var(--ease-out);
}

.btn:hover, .btn:focus-visible {
  transform: translateY(-3px);
  box-shadow: var(--glow-md), var(--shadow-lg);
  color: var(--btn-ink);
}

.btn:hover::before, .btn:focus-visible::before { transform: translateX(120%); }

.btn:active { transform: translateY(-1px); }

.btn--lg { padding: var(--space-6) var(--space-12); font-size: var(--text-base); }

/* Outline variant for use on paper sections. */
.btn--ghost {
  background: transparent;
  border: 1.5px solid var(--color-primary);
  color: var(--color-primary);
  box-shadow: none;
}
.btn--ghost::before { display: none; }
.btn--ghost:hover {
  background: var(--gradient-gold-soft);
  color: var(--color-ink);
  box-shadow: var(--glow-sm);
}

@media (prefers-reduced-motion: reduce) {
  .btn, .btn::before { transition: none; }
  .btn:hover { transform: none; }
}