/* ==========================================================================
   footer.css — shared footer component. See plans/landing.MD §8.
   ========================================================================== */

.site-footer {
  background: #1C2E2B;
  background-image:
    radial-gradient(70% 120% at 12% 0%, rgba(0,150,130,.16) 0%, transparent 62%),
    linear-gradient(180deg, #1C2E2B 0%, #10201D 100%);
  color: var(--text-inverse-muted);
}

.site-footer__grid {
  display: grid;
  grid-template-columns: 1.6fr 1fr 1.3fr 1fr;
  gap: var(--space-12) var(--space-8);
  padding-block: var(--space-20) var(--space-12);
}

/* -- Column 1: brand -- */
.footer-brand__name {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 21px;
  color: #fff;
  margin-bottom: var(--space-4);
}
.footer-brand__line {
  font-size: var(--fs-small);
  color: var(--text-inverse-muted);
  max-width: 34ch;
  line-height: 1.6;
  margin-bottom: var(--space-6);
}
.footer-kit {
  display: inline-flex;
}
.footer-kit .kit-logo-chip {
  transition: opacity var(--dur-base) var(--ease-out);
  opacity: .92;
}
@media (hover: hover) {
  .footer-kit:hover .kit-logo-chip { opacity: 1; }
}
.footer-kit img {
  display: block;
  height: 30px;
  width: auto;
}

/* -- Columns 2-4 -- */
.footer-col__title {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--green-400);
  margin-bottom: var(--space-4);
}
.footer-col ul {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.footer-col a {
  color: var(--text-inverse-muted);
  text-decoration: underline;
  text-decoration-color: transparent;
  text-underline-offset: 4px;
  text-decoration-thickness: 1px;
  transition: color var(--dur-fast) var(--ease-out),
              text-decoration-color var(--dur-fast) var(--ease-out);
}
@media (hover: hover) {
  .footer-col a:hover {
    color: #fff;
    text-decoration-color: var(--green-400);
  }
}

/* -- Column 3: contact -- */
.footer-contact {
  border-left: 1px solid rgba(0,150,130,.35);
  padding-left: var(--space-4);
}
.footer-contact p {
  line-height: 1.75;
  font-size: var(--fs-meta);
  color: var(--text-inverse-muted);
  max-width: none;
  white-space: nowrap;
}
.footer-contact p.footer-contact__building {
  color: #8FA09D;
}
.footer-contact__link-row {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
}
.footer-contact__link-row svg {
  width: 12px;
  height: 12px;
  color: var(--green-400);
  flex-shrink: 0;
}
.footer-contact a {
  font-size: var(--fs-meta);
  color: #fff;
  white-space: nowrap;
  text-decoration: underline;
  text-decoration-color: rgba(0,150,130,.55);
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  transition: text-decoration-color var(--dur-fast) var(--ease-out);
}
@media (hover: hover) {
  .footer-contact a:hover {
    text-decoration-color: var(--kit-green);
    text-decoration-style: solid;
  }
}

/* -- Address block doubles as a Google Maps link — wraps block-level <p>s,
   so it skips the underline styled above (inconsistent across browsers once
   an <a> contains block children) and signals itself on hover instead. -- */
.footer-contact__map {
  display: block;
  text-decoration: none;
}
@media (hover: hover) {
  .footer-contact__map:hover p {
    color: #fff;
  }
}

/* -- Bottom bar -- */
.site-footer__bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-block: var(--space-6);
  border-top: 1px solid rgba(255,255,255,.10);
}
.footer-copyright {
  font-size: 13px;
  color: #8FA09D;
}
.footer-built {
  font-size: 13px;
  color: #8FA09D;
}

/* -- Back to top (§8.8) -- */
.back-to-top {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: 1px solid rgba(255,255,255,.18);
  background: transparent;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: border-color var(--dur-base) var(--ease-out),
              background-color var(--dur-base) var(--ease-out);
}
.back-to-top svg {
  width: 12px;
  height: 12px;
  color: #C9D3D1;
  transition: transform var(--dur-base) var(--ease-out), color var(--dur-base) var(--ease-out);
}
@media (hover: hover) {
  .back-to-top:hover {
    border-color: var(--green-400);
    background: rgba(0,150,130,.14);
  }
  .back-to-top:hover svg {
    color: #fff;
    transform: translateY(-1px);
  }
}

.site-footer :focus-visible {
  outline-color: var(--green-400);
  outline-offset: 3px;
}

/* ==========================================================================
   Responsive (§8.3)
   ========================================================================== */
@media (max-width: 1023px) {
  .site-footer__grid {
    grid-template-columns: 1fr 1fr;
  }
  .footer-brand { grid-column: 1 / -1; }
}

@media (max-width: 639px) {
  .site-footer__grid {
    grid-template-columns: 1fr;
  }
  .footer-brand { order: 1; }
  .footer-col--contact { order: 2; }
  .footer-col--nav { order: 3; }
  .footer-col--institute { order: 4; }

  .site-footer__bar {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-2);
  }
  /* Second row keeps back-to-top pinned to the right edge (§12) */
  .site-footer__bar > div { width: 100%; justify-content: space-between; }
}

/* -- Touch targets: 44x44px minimum on touch input (§12) -- */
@media (hover: none) {
  .back-to-top { width: 44px; height: 44px; }
}