.heritage-gallery{
  padding: 100px 0;
  background: #fff; /* yes: white */
}

.gallery-grid{
  display:grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  margin-top: 40px;
}

.gthumb{
  display:block;
  border-radius: 12px;
  overflow:hidden;
  box-shadow: 0 10px 26px rgba(0,0,0,.06);
  transition: transform .25s ease, box-shadow .25s ease;
  background:#fff;
}

.gthumb img{
  width:100%;
  height: 220px;
  object-fit: cover;
  display:block;
  transition: transform .35s ease;
}

.gthumb:hover{
  transform: translateY(-4px);
  box-shadow: 0 14px 34px rgba(0,0,0,.10);
}
.gthumb:hover img{ transform: scale(1.05); }

/* Lightbox (CSS :target) */
.lightbox{
  position: fixed;
  inset: 0;
  display: none;
  z-index: 9999;
}

.lightbox:target{
  display: block;
}

.lb-backdrop{
  position:absolute;
  inset:0;
  background: rgba(0,0,0,.78);
}

.lb-figure{
  position: relative;
  z-index: 1;
  max-width: 1100px;
  margin: 60px auto;
  padding: 18px;
  border-radius: 14px;
  background: #111;
  box-shadow: 0 20px 60px rgba(0,0,0,.45);
}

.lb-figure img{
  width:100%;
  height:auto;
  display:block;
  border-radius: 10px;
}

.lb-figure figcaption{
  margin-top: 12px;
  color: rgba(255,255,255,.85);
  font-size: 14px;
}

.lb-close{
  position: absolute;
  top: 18px;
  right: 22px;
  z-index: 2;
  width: 44px;
  height: 44px;
  border-radius: 999px;
  background: rgba(255,255,255,.12);
  color: #fff;
  text-decoration: none;
  font-size: 30px;
  line-height: 44px;
  text-align: center;
  backdrop-filter: blur(6px);
}

.lb-close:hover{
  background: rgba(255,255,255,.2);
}

/* Responsive */
@media (max-width: 980px){
  .gallery-grid{ grid-template-columns: repeat(2, 1fr); }
  .gthumb img{ height: 200px; }
  .lb-figure{ margin: 40px 16px; }
}
@media (max-width: 560px){
  .gallery-grid{ grid-template-columns: 1fr; }
  .gthumb img{ height: 220px; }
}