/* ============================================================
   FOOTER.CSS — BangDinhNhom Theme
   Footer Main | Footer Bottom | Back To Top
   ============================================================ */

/* ── FOOTER MAIN ─────────────────────────────────────────── */
.site-footer {
  background: #0a1929;
  color: rgba(255,255,255,.75);
  position: relative;
}

.site-footer::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--color-primary), var(--color-accent), var(--color-primary));
}

.footer-main {
  padding: 4rem 0 2.5rem;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.8fr 1fr 1fr 1fr;
  gap: 3rem;
}

/* Footer brand column */
.footer-brand {}

.footer-logo {
  display: flex;
  align-items: center;
  gap: .6rem;
  text-decoration: none;
  margin-bottom: 1.25rem;
}

.footer-logo img {
  height: 40px;
  width: auto;
  filter: brightness(0) invert(1);
}

.footer-logo-text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.footer-logo-main {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.1rem;
  color: #fff;
  text-transform: uppercase;
  letter-spacing: .04em;
}

.footer-logo-sub {
  font-size: .58rem;
  color: rgba(255,255,255,.45);
  text-transform: uppercase;
  letter-spacing: .08em;
}

.footer-tagline {
  font-size: .88rem;
  line-height: 1.65;
  color: rgba(255,255,255,.6);
  margin-bottom: 1.5rem;
  max-width: 280px;
}

.footer-contact-list {
  display: flex;
  flex-direction: column;
  gap: .65rem;
  margin-bottom: 1.5rem;
}

.footer-contact-item {
  display: flex;
  align-items: flex-start;
  gap: .6rem;
  font-size: .84rem;
  color: rgba(255,255,255,.65);
  text-decoration: none;
  transition: color .2s;
}

.footer-contact-item:hover { color: #fff; }

.footer-contact-item svg {
  width: 15px;
  height: 15px;
  color: var(--color-accent);
  flex-shrink: 0;
  margin-top: .1rem;
}

.footer-social {
  display: flex;
  gap: .5rem;
}

.footer-social-link {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: rgba(255,255,255,.08);
  border: 1px solid rgba(255,255,255,.12);
  display: flex;
  align-items: center;
  justify-content: center;
  color: rgba(255,255,255,.6);
  text-decoration: none;
  transition: background .2s, color .2s, border-color .2s;
}

.footer-social-link:hover {
  background: var(--color-accent);
  border-color: var(--color-accent);
  color: #fff;
}

.footer-social-link svg { width: 15px; height: 15px; }

/* Footer nav columns */
.footer-col {}

.footer-col-title {
  font-family: var(--font-display);
  font-size: .8rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .1em;
  color: #fff;
  margin-bottom: 1.25rem;
  padding-bottom: .6rem;
  border-bottom: 1px solid rgba(255,255,255,.1);
  display: flex;
  align-items: center;
  gap: .5rem;
}

.footer-col-title::before {
  content: '';
  display: block;
  width: 14px;
  height: 2px;
  background: var(--color-accent);
  flex-shrink: 0;
}

.footer-nav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: .5rem;
}

.footer-nav-list li a {
  font-size: .84rem;
  color: rgba(255,255,255,.6);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: .4rem;
  transition: color .2s, gap .2s;
}

.footer-nav-list li a::before {
  content: '›';
  color: var(--color-accent);
  font-size: .9rem;
  line-height: 1;
}

.footer-nav-list li a:hover {
  color: #fff;
  gap: .6rem;
}

/* Cert badges in footer */
.footer-cert-badges {
  display: flex;
  gap: .5rem;
  flex-wrap: wrap;
  margin-top: 1.25rem;
}

.footer-cert-badge {
  padding: .35rem .75rem;
  border: 1px solid rgba(255,255,255,.15);
  border-radius: var(--radius-sm);
  font-size: .65rem;
  font-weight: 700;
  color: rgba(255,255,255,.6);
  text-transform: uppercase;
  letter-spacing: .06em;
  display: flex;
  align-items: center;
  gap: .3rem;
}

.footer-cert-badge svg {
  width: 12px;
  height: 12px;
  color: var(--color-accent);
}

/* ── FOOTER BOTTOM ───────────────────────────────────────── */
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,.08);
  padding: 1.25rem 0;
}

.footer-bottom-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.footer-copyright {
  font-size: .78rem;
  color: rgba(255,255,255,.4);
  line-height: 1.5;
}

.footer-copyright a {
  color: rgba(255,255,255,.6);
  text-decoration: none;
  transition: color .2s;
}

.footer-copyright a:hover { color: #fff; }

.footer-bottom-links {
  display: flex;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.footer-bottom-links a {
  font-size: .75rem;
  color: rgba(255,255,255,.4);
  text-decoration: none;
  transition: color .2s;
}

.footer-bottom-links a:hover { color: rgba(255,255,255,.7); }

.footer-gov-badge {
  display: flex;
  align-items: center;
  gap: .35rem;
}

.footer-gov-badge img {
  height: 28px;
  width: auto;
  opacity: .6;
}

.footer-gov-badge span {
  font-size: .7rem;
  color: rgba(255,255,255,.35);
}

/* ── BACK TO TOP ─────────────────────────────────────────── */
.back-to-top {
  position: fixed;
  bottom: 5rem;
  right: 1.5rem;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--color-primary);
  color: #fff;
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: var(--shadow-md);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity .3s, visibility .3s, transform .3s, background .2s;
  z-index: 150;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover { background: var(--color-primary-dark); }
.back-to-top svg { width: 18px; height: 18px; }

@media (max-width: 768px) {
  .back-to-top { bottom: 6rem; right: 1rem; }
}

/* ── RESPONSIVE FOOTER ───────────────────────────────────── */
@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 2rem; }
  .footer-brand { grid-column: span 2; }
}

@media (max-width: 640px) {
  .footer-grid { grid-template-columns: 1fr; }
  .footer-brand { grid-column: auto; }
  .footer-bottom-inner { flex-direction: column; text-align: center; }
  .footer-bottom-links { justify-content: center; }
}