:root {
  --thumb-size: 200px;
}

body {
  font-family: Arial, sans-serif;
  background: #f4f4f4;
  color: #333;
  margin: 0;
  padding: 20px;
}

header, footer {
  text-align: center;
  margin-bottom: 20px;
}

.content-block {
    max-width: 80%;
    margin: auto;
}

.gallery {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(var(--thumb-size), 1fr));
  gap: 10px;
}

.gallery img {
  width: 100%;
  height: var(--thumb-size);
  object-fit: cover;
  object-position: center;
  border-radius: 5px;
  display: block;
  cursor: pointer;
  transition: transform 0.3s ease;
}

.gallery img:hover {
  transform: scale(1.02);
}

/* Lightbox base */
.lightbox {
  display: none;
  position: fixed;
  z-index: 1000;
  top: 0; left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.9);
  justify-content: center;
  align-items: center;
  text-align: center;
  padding: 20px 0;
}

/* Targeted lightbox visible */
.lightbox:target {
  display: flex;
  animation: fadeInZoom 0.5s ease forwards;
}

.lightbox-content {
  max-width: 80%;
  max-height: 80%;
}

.lightbox img {
  max-width: 100%;
  max-height: 80vh;
  border-radius: 8px;
  box-shadow: 0 0 25px rgba(255,255,255,0.15);
  opacity: 0;
  transform: scale(0.9);
  animation: fadeZoom 0.5s ease forwards;
}

.caption {
  color: #fff;
  margin-top: 10px;
  margin-bottom: 15px;
  font-size: 1rem;
}

/* Close button */
.close {
  position: absolute;
  top: 20px;
  right: 50px;
  font-size: 40px;
  color: white;
  text-decoration: none;
  font-weight: bold;
}

/* Prev/Next navigation */
.nav {
  position: absolute;
  top: 50%;
  font-size: 50px;
  color: #fff;
  text-decoration: none;
  padding: 10px;
  border-radius: 50%;
  background: rgba(0,0,0,0);
  transform: translateY(-50%);
  transition: background 0.3s ease;
}

.nav:hover {
  background: rgba(255,255,255,0.0);
}

.nav.prev { left: 20px; }
.nav.next { right: 20px; }

/* Animations */
@keyframes fadeInZoom {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes fadeZoom {
  to {
    opacity: 1;
    transform: scale(1);
  }
}