/* buttons — 8-state discipline */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2xs);
  height: 44px;
  padding: 0 1.25rem;
  font-family: var(--font-mono);
  font-size: var(--text-sm);
  font-weight: 500;
  letter-spacing: -0.005em;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  background: transparent;
  color: var(--color-ink);
  cursor: pointer;
  white-space: nowrap;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  transition:
    background var(--dur-short) var(--ease-out),
    color var(--dur-short) var(--ease-out),
    border-color var(--dur-short) var(--ease-out),
    transform var(--dur-short) var(--ease-out);
}
.btn:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 3px;
}
.btn:disabled,
.btn[aria-disabled="true"] {
  cursor: not-allowed;
  opacity: 0.45;
  pointer-events: none;
}

/* primary — solid violet */
.btn-primary {
  background: var(--color-accent);
  color: var(--color-accent-ink);
  border-color: var(--color-accent);
}
.btn-primary:hover { background: var(--color-accent-2); border-color: var(--color-accent-2); }
.btn-primary:active { transform: translateY(1px); }

/* outline-chip */
.btn-chip {
  background: transparent;
  color: var(--color-ink);
  border-color: var(--color-rule);
}
.btn-chip:hover { border-color: var(--color-accent); color: var(--color-accent-2); }
.btn-chip:active { transform: translateY(1px); }

/* ghost — secondary text-button */
.btn-ghost {
  background: transparent;
  color: var(--color-ink-2);
  border-color: transparent;
}
.btn-ghost:hover { color: var(--color-ink); }
.btn-ghost:active { transform: translateY(1px); }

/* arrow glyph */
.btn .arrow {
  display: inline-block;
  transition: transform var(--dur-short) var(--ease-out);
}
.btn:hover .arrow { transform: translateX(3px); }

/* card — used by cap-card / how-step */
.card {
  background: var(--color-paper-2);
  border: 1px solid var(--color-rule);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  transition: border-color var(--dur-short) var(--ease-out);
}
.card:hover { border-color: var(--color-rule-2); }

/* badge */
.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3xs);
  height: 22px;
  padding: 0 var(--space-2xs);
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  background: var(--color-paper-3);
  border: 1px solid var(--color-rule);
  border-radius: var(--radius-sm);
  color: var(--color-ink-2);
  font-variant-numeric: tabular-nums;
}
.badge-success {
  color: var(--color-success);
  border-color: var(--color-success-ring);
  background: var(--color-success-tint);
}

/* accordion */
.accordion-item { border-top: 1px solid var(--color-rule); }
.accordion-item:last-child { border-bottom: 1px solid var(--color-rule); }
.accordion-trigger {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-md);
  background: transparent;
  border: 0;
  color: var(--color-ink);
  font: inherit;
  font-family: var(--font-body);
  font-size: var(--text-lg);
  font-weight: 500;
  letter-spacing: -0.01em;
  padding: var(--space-md) 0;
  cursor: pointer;
  text-align: left;
  transition: color var(--dur-short) var(--ease-out);
}
.accordion-trigger:hover { color: var(--color-accent-2); }
.accordion-trigger:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 4px;
  border-radius: var(--radius-sm);
}
.accordion-trigger .chevron {
  transition: transform var(--dur-short) var(--ease-out);
  color: var(--color-muted);
  flex-shrink: 0;
}
.accordion-trigger[aria-expanded="true"] .chevron {
  transform: rotate(180deg);
  color: var(--color-accent-2);
}
.accordion-panel {
  overflow: hidden;
  height: 0;
  color: var(--color-ink-2);
}
.accordion-panel-inner { padding-bottom: var(--space-md); max-width: 64ch; }

/* marquee — pause on hover, respect reduced motion */
.marquee {
  overflow: hidden;
  mask-image: linear-gradient(90deg, transparent, #000 12%, #000 88%, transparent);
  -webkit-mask-image: linear-gradient(90deg, transparent, #000 12%, #000 88%, transparent);
}
.marquee-track {
  display: flex;
  gap: var(--space-3xl);
  width: max-content;
  animation: marquee 36s linear infinite;
}
.marquee:hover .marquee-track,
.marquee:focus-within .marquee-track { animation-play-state: paused; }
@keyframes marquee {
  from { transform: translate3d(0, 0, 0); }
  to   { transform: translate3d(-50%, 0, 0); }
}
@media (prefers-reduced-motion: reduce) {
  .marquee-track { animation: none; transform: none; }
}

/* reveal */
[data-reveal] { opacity: 0; transform: translateY(12px); }
[data-reveal].is-visible {
  opacity: 1;
  transform: none;
  transition: opacity var(--dur-long) var(--ease-out), transform var(--dur-long) var(--ease-out);
}
@media (prefers-reduced-motion: reduce) {
  [data-reveal] { opacity: 1; transform: none; }
  [data-reveal].is-visible { transition: opacity 0.01ms; }
}

/* ---- theme switcher (floating pill, bottom-right) ---- */
.theme-switcher {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 900;
  display: flex;
  background: var(--color-paper-2);
  border: 1px solid var(--color-rule);
  border-radius: var(--radius-pill);
  padding: 4px;
  gap: 2px;
  box-shadow: 0 4px 24px oklch(0% 0 0 / 0.25);
  transition: background var(--dur-short) var(--ease-out),
              border-color var(--dur-short) var(--ease-out);
}

.theme-btn {
  display: flex;
  align-items: center;
  gap: 5px;
  padding: 6px 12px;
  border-radius: var(--radius-pill);
  border: none;
  background: transparent;
  color: var(--color-muted);
  font-family: var(--font-body);
  font-size: var(--text-sm);
  font-weight: 500;
  cursor: pointer;
  transition: background var(--dur-short) var(--ease-out),
              color var(--dur-short) var(--ease-out);
  -webkit-tap-highlight-color: transparent;
}

.theme-btn[aria-pressed="true"] {
  background: var(--color-accent);
  color: var(--color-accent-ink);
  font-weight: 600;
}

.theme-btn:hover:not([aria-pressed="true"]) {
  color: var(--color-ink);
}

.theme-btn:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 2px;
}

/* jump to top — appears on long-scroll pages past one viewport */
.to-top {
  position: fixed;
  right: 24px;
  bottom: 104px; /* sits above .theme-switcher (bottom: 24px, ~60px tall, +gap) */
  z-index: 60;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  padding: 0;
  border-radius: var(--radius-pill);
  border: 1px solid var(--color-rule);
  background: var(--color-paper-2);
  color: var(--color-ink-2);
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transform: translateY(8px);
  transition:
    opacity var(--dur-med) var(--ease-out),
    transform var(--dur-med) var(--ease-out),
    color var(--dur-short) var(--ease-out),
    border-color var(--dur-short) var(--ease-out),
    background var(--dur-short) var(--ease-out);
  -webkit-tap-highlight-color: transparent;
}
.to-top.is-visible {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}
.to-top:hover {
  color: var(--color-ink);
  border-color: var(--color-accent);
  background: var(--color-paper-3);
}
.to-top:active { transform: translateY(1px); }
.to-top:focus-visible {
  outline: 2px solid var(--color-focus);
  outline-offset: 3px;
}
.to-top svg { width: 18px; height: 18px; }

@media (prefers-reduced-motion: reduce) {
  .to-top { transition: opacity var(--dur-short) linear; transform: none; }
  .to-top.is-visible { transform: none; }
}