/**
 * Aira Antivirus — Stage 7: FAQ (Frequently Asked Questions)
 * Visual Direction: Premium Cybersecurity × AI Infrastructure
 * Adheres strictly to:
 * - tokens.css design system
 * - better-accessibility (ARIA APG Accordion, visible focus rings, 44px hit targets)
 * - better-colors (WCAG 2.1 AA contrast ratios)
 * - frontend-ui-engineering (fluid type, 0 horizontal overflow, responsive padding)
 */

/* ==========================================================================
   1. FAQ Section Shell & Ambient Lighting
   ========================================================================== */

.faq-section {
  position: relative;
  padding-block: clamp(3.5rem, 7vw, 6.5rem);
  background-color: var(--surface-canvas);
  border-top: 1px solid var(--border-subtle);
  overflow: hidden;
}

.faq__glow {
  position: absolute;
  top: 10%;
  left: 50%;
  transform: translateX(-50%);
  width: min(800px, 90vw);
  height: 380px;
  background: radial-gradient(
    ellipse at center,
    rgba(59, 102, 255, 0.06) 0%,
    rgba(6, 182, 212, 0.03) 40%,
    transparent 70%
  );
  pointer-events: none;
  z-index: 0;
}

.faq__container {
  position: relative;
  z-index: 1;
  max-width: 880px;
  margin-inline: auto;
}

/* ==========================================================================
   2. Section Header
   ========================================================================== */

.faq__header {
  text-align: center;
  margin-bottom: clamp(2rem, 4vw, 3.5rem);
}

.faq__header .section-label {
  margin-bottom: var(--space-2);
}

.faq__title {
  font-family: var(--font-sans);
  font-size: var(--text-3xl);
  font-weight: var(--weight-bold);
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
  color: var(--text-primary);
  margin-bottom: var(--space-3);
  text-wrap: balance;
}

.faq__subtitle {
  font-size: var(--text-base);
  line-height: var(--leading-relaxed);
  color: var(--text-secondary);
  max-width: 54ch;
  margin-inline: auto;
  text-wrap: balance;
}

/* ==========================================================================
   3. Accordion List & Item Cards
   ========================================================================== */

.faq-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.faq-item {
  background-color: var(--surface-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  transition:
    border-color var(--transition-normal),
    background-color var(--transition-normal),
    box-shadow var(--transition-normal);
  overflow: hidden;
}

.faq-item:hover {
  border-color: var(--border-default);
  background-color: rgba(20, 27, 38, 0.85);
}

.faq-item.is-open {
  border-color: var(--border-accent);
  background-color: var(--surface-card);
  box-shadow:
    0 4px 20px rgba(0, 0, 0, 0.4),
    0 0 24px rgba(59, 102, 255, 0.08);
}

/* ==========================================================================
   4. Accordion Trigger Button
   ========================================================================== */

.faq-item__heading {
  margin: 0;
  padding: 0;
  font-size: 1rem;
  font-weight: inherit;
}

.faq-trigger {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  width: 100%;
  min-height: var(--hit-target-min);
  padding: clamp(1rem, 2.5vw, 1.35rem) clamp(1rem, 3vw, 1.5rem);
  background: transparent;
  border: none;
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: var(--text-md);
  font-weight: var(--weight-semibold);
  line-height: var(--leading-snug);
  text-align: left;
  cursor: pointer;
  border-radius: var(--radius-lg);
  transition: color var(--transition-fast);
}

.faq-trigger:focus {
  outline: none;
}

.faq-trigger:focus-visible {
  outline: 2px solid var(--color-accent-400);
  outline-offset: -2px;
}

.faq-trigger__text {
  flex: 1;
}

.faq-trigger__icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background-color: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-subtle);
  flex-shrink: 0;
  perspective: 90px;
  transform-style: preserve-3d;
  position: relative;
  overflow: visible;
  transition:
    background-color var(--transition-normal),
    border-color var(--transition-normal);
}

.faq-item:hover .faq-trigger__icon {
  border-color: var(--border-default);
  background-color: rgba(255, 255, 255, 0.07);
}

.faq-item.is-open .faq-trigger__icon {
  background-color: rgba(59, 102, 255, 0.16);
  border-color: var(--border-accent);
}

.faq-depth-plane {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  backface-visibility: hidden;
  transition: transform 340ms cubic-bezier(0.16, 1, 0.3, 1), opacity 260ms ease, filter 260ms ease;
}

.faq-depth-plane--down {
  color: var(--color-neutral-400);
  transform: translateZ(0) scale(1);
  opacity: 1;
  filter: blur(0);
}

.faq-depth-plane--up {
  color: var(--color-cyan-400);
  transform: translateZ(16px) scale(1.3);
  opacity: 0;
  filter: blur(3px);
}

.faq-item.is-open .faq-depth-plane--down {
  transform: translateZ(-16px) scale(0.65);
  opacity: 0;
  filter: blur(3px);
}

.faq-item.is-open .faq-depth-plane--up {
  transform: translateZ(0) scale(1);
  opacity: 1;
  filter: blur(0) drop-shadow(0 0 4px rgba(56, 189, 248, 0.7));
}

@media (prefers-reduced-motion: reduce) {
  .faq-depth-plane {
    transition: opacity 150ms ease;
    transform: none !important;
    filter: none !important;
  }
}

/* ==========================================================================
   5. Accordion Panel & Smooth Grid Row Expansion
   ========================================================================== */

.faq-panel {
  display: grid;
  grid-template-rows: 0fr;
  transition: grid-template-rows var(--transition-normal), visibility var(--transition-normal);
  visibility: hidden;
}

.faq-item.is-open .faq-panel {
  grid-template-rows: 1fr;
  visibility: visible;
}

.faq-panel__inner {
  overflow: hidden;
  padding-inline: clamp(1rem, 3vw, 1.5rem);
  padding-bottom: clamp(1rem, 2.5vw, 1.35rem);
}

.faq-panel__divider {
  height: 1px;
  background-color: var(--border-subtle);
  margin-bottom: var(--space-4);
}

.faq-panel__text {
  font-size: var(--text-base);
  line-height: var(--leading-relaxed);
  color: var(--text-secondary);
  margin: 0;
}

/* ==========================================================================
   6. Reduced Motion Support
   ========================================================================== */

@media (prefers-reduced-motion: reduce) {
  .faq-item,
  .faq-trigger,
  .faq-trigger__icon,
  .faq-panel {
    transition: none !important;
  }
}