/**
 * Aira Antivirus — Stage 7: Footer Component
 * Visual Direction: Premium Cybersecurity × AI Infrastructure
 * Adheres strictly to:
 * - tokens.css design system
 * - better-accessibility (WCAG 2.1 AA contrast, visible focus, 44px touch targets)
 * - better-colors (semantic surface tokens, AA/AAA contrast)
 * - frontend-ui-engineering (responsive fluid grid, zero overflow, mobile stacking)
 */

/* ==========================================================================
   1. Footer Shell & Hairline Separator
   ========================================================================== */

.site-footer {
  position: relative;
  background-color: var(--surface-subtle);
  border-top: 1px solid var(--border-default);
  padding-block: clamp(3rem, 6vw, 5rem) clamp(2rem, 4vw, 3rem);
  overflow: hidden;
}

.footer__glow {
  position: absolute;
  bottom: 0;
  left: 50%;
  transform: translateX(-50%);
  width: min(900px, 95vw);
  height: 250px;
  background: radial-gradient(
    ellipse at center bottom,
    rgba(59, 102, 255, 0.05) 0%,
    rgba(6, 182, 212, 0.02) 50%,
    transparent 80%
  );
  pointer-events: none;
  z-index: 0;
}

.footer__container {
  position: relative;
  z-index: 1;
}

/* ==========================================================================
   2. Main Footer Multi-Column Grid
   ========================================================================== */

.footer__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: clamp(2rem, 4vw, 3rem);
}

@media (min-width: 641px) and (max-width: 1023px) {
  .footer__grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .footer__grid {
    grid-template-columns: 2fr 1fr 1fr 1.3fr;
    gap: var(--space-8);
  }
}

/* ==========================================================================
   3. Column 1: Brand & Mission
   ========================================================================== */

.footer__col--brand {
  display: flex;
  flex-direction: column;
}

.footer__brand {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  margin-bottom: var(--space-3);
  width: fit-content;
}

.footer__brand-wrap {
  display: inline-flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 1px;
}

.footer__brand-logo {
  height: 32px;
  width: auto;
  max-width: 100%;
  aspect-ratio: 640 / 210;
  display: block;
  object-fit: contain;
  filter: drop-shadow(0 0 10px rgba(59, 102, 255, 0.35));
  transition: filter var(--transition-fast), transform var(--transition-fast);
}

.footer__brand-descriptor {
  font-family: var(--font-mono);
  font-size: 0.6rem; /* 9px */
  font-weight: var(--weight-bold);
  letter-spacing: 0.59em;
  margin-right: -0.59em; /* Trims trailing tracking for pixel-exact end-to-end alignment */
  text-transform: uppercase;
  color: var(--color-neutral-400);
  line-height: 1;
  padding-left: 1px;
  transition: color var(--transition-fast);
  display: inline-flex;
  user-select: none;
}

@media (max-width: 767px) {
  .footer__brand-logo {
    height: 26px;
  }

  .footer__brand-descriptor {
    font-size: 0.495rem; /* 7.5px */
    letter-spacing: 0.57em;
    margin-right: -0.57em;
    padding-left: 0.5px;
  }
}

.footer__desc {
  font-size: var(--text-sm);
  line-height: var(--leading-relaxed);
  color: var(--text-secondary);
  margin: 0 0 var(--space-4) 0;
  max-width: 44ch;
}

.footer__status {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: 6px 12px;
  background-color: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-full);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  color: var(--text-tertiary);
  width: fit-content;
}

.footer__status-dot {
  width: 6px;
  height: 6px;
  border-radius: var(--radius-full);
  background-color: var(--color-emerald-400);
  box-shadow: 0 0 8px rgba(16, 185, 129, 0.6);
}

.footer__status::after {
  content: none !important;
}

/* ==========================================================================
   4. Navigation & Link Columns
   ========================================================================== */

.footer__col-title {
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  font-weight: var(--weight-semibold);
  text-transform: uppercase;
  letter-spacing: var(--tracking-wider);
  color: var(--text-primary);
  margin: 0 0 var(--space-4) 0;
}

.footer__links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
}

.footer__link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  min-height: 36px;
  padding-block: 4px;
  font-size: var(--text-sm);
  color: var(--text-secondary);
  text-decoration: none;
  transition: color var(--transition-fast), transform var(--transition-fast);
}

.footer__link:hover {
  color: var(--text-accent-bright);
}

.footer__link:focus-visible {
  outline: 2px solid var(--color-accent-400);
  outline-offset: 2px;
  border-radius: var(--radius-xs);
}

.footer__external-icon {
  width: 12px;
  height: 12px;
  opacity: 0.7;
  flex-shrink: 0;
}

/* ==========================================================================
   5. Column 4: Quick Start CTA Block
   ========================================================================== */

.footer__col--cta {
  display: flex;
  flex-direction: column;
}

.footer__cta-card {
  background-color: var(--surface-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: clamp(1rem, 2.5vw, 1.25rem);
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
}

.footer__cta-desc {
  font-size: var(--text-xs);
  line-height: var(--leading-normal);
  color: var(--text-secondary);
  margin: 0;
}

.footer__cta-btn {
  width: 100%;
  justify-content: center;
}

/* ==========================================================================
   6. Footer Bottom Bar: Copyright & Back to Top
   ========================================================================== */

.footer__bottom {
  margin-top: clamp(2.5rem, 5vw, 4rem);
  padding-top: var(--space-6);
  border-top: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-4);
}

.footer__bottom-left {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.footer__copyright {
  font-size: var(--text-xs);
  color: var(--text-tertiary);
  line-height: var(--leading-normal);
  margin: 0;
}

.footer__legal-links {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--text-xs);
  color: var(--text-tertiary);
}

.footer__legal-sep {
  color: var(--color-neutral-600);
  user-select: none;
}

.footer__copyright-link {
  color: var(--text-secondary);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  padding-block: 2px;
  transition: color var(--transition-fast);
}

.footer__copyright-link:hover {
  color: var(--text-accent-bright);
}

.footer__copyright-link:focus-visible {
  outline: 2px solid var(--color-accent-400);
  outline-offset: 2px;
  border-radius: var(--radius-xs);
}

.footer__back-to-top {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  min-height: var(--hit-target-min);
  padding: 8px 16px;
  background-color: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: var(--text-xs);
  cursor: pointer;
  text-decoration: none;
  transition:
    background-color var(--transition-fast),
    border-color var(--transition-fast),
    color var(--transition-fast);
}

.footer__back-to-top:hover {
  background-color: rgba(255, 255, 255, 0.07);
  border-color: var(--border-default);
  color: var(--text-primary);
}

.footer__back-to-top:focus-visible {
  outline: 2px solid var(--color-accent-400);
  outline-offset: 2px;
}

.footer__back-to-top-icon {
  width: 14px;
  height: 14px;
  flex-shrink: 0;
}

/* ==========================================================================
   7. Mobile Touch Target Standards
   ========================================================================== */

@media (max-width: 640px) {
  .site-footer {
    padding-block: var(--space-8) var(--space-5);
  }

  .footer__grid {
    gap: var(--space-5);
  }

  .footer__brand {
    margin-bottom: var(--space-2);
  }

  .footer__desc {
    margin-bottom: var(--space-3);
    font-size: var(--text-xs);
    line-height: var(--leading-normal);
  }

  .footer__status {
    padding: 4px 10px;
    font-size: 0.72rem;
  }

  .footer__col-title {
    margin: 0 0 var(--space-2) 0;
    font-size: 0.6875rem;
  }

  .footer__links {
    gap: 2px;
  }

  .footer__link {
    min-height: 34px;
    padding-block: 4px;
    font-size: var(--text-xs);
    line-height: 1.4;
  }

  .footer__cta-card {
    padding: var(--space-3);
    gap: var(--space-2);
  }

  .footer__cta-desc {
    font-size: 0.75rem;
    line-height: 1.45;
  }

  .footer__cta-btn {
    min-height: 38px;
    padding: 8px 14px;
    font-size: var(--text-xs);
  }

  .footer__bottom {
    margin-top: var(--space-6);
    padding-top: var(--space-4);
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-3);
  }

  .footer__bottom-left {
    gap: var(--space-1);
  }

  .footer__copyright {
    font-size: 0.72rem;
    line-height: 1.45;
  }

  .footer__legal-links {
    flex-wrap: wrap;
    gap: var(--space-1) var(--space-2);
    font-size: 0.72rem;
  }

  .footer__copyright-link {
    min-height: auto;
    padding-block: 3px;
    font-size: 0.72rem;
  }

  .footer__back-to-top {
    width: 100%;
    justify-content: center;
    min-height: 38px;
    padding: 8px 14px;
    font-size: var(--text-xs);
    margin-top: 2px;
  }
}