/* ============================================================
   Accordion Slider Module — Styles
   Horizontal + vertical expandable accordion panels.
   ============================================================ */

.accordion-slider {
  display: flex;
  width: 100%;
  height: 100%;
  min-height: 400px;
  gap: var(--cs-space-xs, 0.25rem);
  overflow: hidden;
  background-color: var(--cs-bg, #0a0a0f);
}

/* ---- Panel ---- */
.accordion-slider__panel {
  position: relative;
  flex: 1;
  min-width: 60px;
  overflow: hidden;
  border-radius: var(--cs-radius-md, 8px);
  background-color: var(--cs-surface, #141420);
  transition: flex var(--cs-duration-slow, 600ms) var(--cs-ease-default, cubic-bezier(0.4, 0, 0.2, 1));
  cursor: pointer;
  outline: none;
}

.accordion-slider__panel:hover {
  background-color: var(--cs-surface-hover, #1e1e30);
}

.accordion-slider__panel--active {
  flex: 3;
}

/* ---- Panel background image ---- */
.accordion-slider__panel-bg {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  opacity: 0.3;
  transition: opacity var(--cs-duration-slow, 600ms) var(--cs-ease-default, cubic-bezier(0.4, 0, 0.2, 1));
  pointer-events: none;
}

.accordion-slider__panel--active .accordion-slider__panel-bg {
  opacity: 0.6;
}

/* ---- Panel header ---- */
.accordion-slider__panel-header {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  padding: var(--cs-space-lg, 1.5rem) var(--cs-space-md, 1rem);
  height: 100%;
  transition: align-items var(--cs-duration-normal, 300ms) var(--cs-ease-default, cubic-bezier(0.4, 0, 0.2, 1));
}

.accordion-slider__panel--active .accordion-slider__panel-header {
  align-items: flex-start;
}

/* ---- Icon ---- */
.accordion-slider__icon {
  font-size: var(--cs-text-2xl, 1.5rem);
  margin-bottom: var(--cs-space-sm, 0.5rem);
  transition: transform var(--cs-duration-normal, 300ms) var(--cs-ease-bounce, cubic-bezier(0.34, 1.56, 0.64, 1));
}

.accordion-slider__panel--active .accordion-slider__icon {
  transform: scale(1.3);
}

/* ---- Title ---- */
.accordion-slider__title {
  font-family: var(--cs-font-heading, sans-serif);
  font-size: var(--cs-text-sm, 0.875rem);
  font-weight: var(--cs-weight-semibold, 600);
  color: var(--cs-text, #f1f5f9);
  letter-spacing: var(--cs-tracking-wide, 0.05em);
  text-transform: uppercase;
  white-space: nowrap;
  writing-mode: vertical-rl;
  text-orientation: mixed;
  transition: writing-mode var(--cs-duration-normal, 300ms),
              font-size var(--cs-duration-normal, 300ms);
}

.accordion-slider__panel--active .accordion-slider__title {
  writing-mode: horizontal-tb;
  font-size: var(--cs-text-xl, 1.25rem);
}

/* ---- Panel content (hidden until expanded) ---- */
.accordion-slider__panel-content {
  position: relative;
  z-index: 1;
  padding: 0 var(--cs-space-lg, 1.5rem);
  opacity: 0;
  max-height: 0;
  overflow: hidden;
  transition: opacity var(--cs-duration-slow, 600ms) var(--cs-ease-default, cubic-bezier(0.4, 0, 0.2, 1)),
              max-height var(--cs-duration-slow, 600ms) var(--cs-ease-default, cubic-bezier(0.4, 0, 0.2, 1));
}

.accordion-slider__panel--active .accordion-slider__panel-content {
  opacity: 1;
  max-height: 200px;
}

/* ---- Description ---- */
.accordion-slider__description {
  font-family: var(--cs-font-body, sans-serif);
  font-size: var(--cs-text-sm, 0.875rem);
  color: var(--cs-muted, #475569);
  line-height: var(--cs-leading-normal, 1.6);
  margin-top: var(--cs-space-md, 1rem);
}

/* ---- Vertical mode ---- */
.accordion-slider--vertical {
  flex-direction: column;
}

.accordion-slider--vertical .accordion-slider__panel {
  min-width: unset;
  min-height: 60px;
  flex: 1;
}

.accordion-slider--vertical .accordion-slider__panel--active {
  flex: 3;
}

.accordion-slider--vertical .accordion-slider__title {
  writing-mode: horizontal-tb;
}

.accordion-slider--vertical .accordion-slider__panel-header {
  flex-direction: row;
  align-items: center;
  gap: var(--cs-space-md, 1rem);
}

.accordion-slider--vertical .accordion-slider__panel--active .accordion-slider__panel-header {
  align-items: flex-start;
}

/* ---- Focus visible for keyboard nav ---- */
.accordion-slider__panel:focus-visible {
  outline: 2px solid var(--cs-primary, #6366f1);
  outline-offset: 2px;
}

/* ---- Responsive: vertical on mobile ---- */
@media (max-width: 768px) {
  .accordion-slider {
    flex-direction: column;
    min-height: 300px;
  }

  .accordion-slider .accordion-slider__panel {
    min-width: unset;
    min-height: 60px;
  }

  .accordion-slider .accordion-slider__title {
    writing-mode: horizontal-tb;
  }

  .accordion-slider .accordion-slider__panel-header {
    flex-direction: row;
    align-items: center;
    gap: var(--cs-space-md, 1rem);
  }

  .accordion-slider .accordion-slider__panel--active .accordion-slider__panel-header {
    align-items: flex-start;
  }
}

@media (max-width: 375px) {
  .accordion-slider {
    min-height: 250px;
  }

  .accordion-slider__title {
    font-size: var(--cs-text-xs, 0.75rem);
  }

  .accordion-slider__panel--active .accordion-slider__title {
    font-size: var(--cs-text-base, 1rem);
  }
}

/* ---- Reduced motion: honour the OS preference (accessibility NFR) ---- */
@media (prefers-reduced-motion: reduce) {
  .accordion-slider__panel,
  .accordion-slider__panel-bg,
  .accordion-slider__panel-header,
  .accordion-slider__panel-content,
  .accordion-slider__icon,
  .accordion-slider__title {
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
  }
}