:root {
  --primary: #00ff88;
  --bg-dark: #0a0a0a;
  --bg-light: #111;
  --text: #fff;
  --glow: 0 0 10px var(--primary), 0 0 20px var(--primary);
}

body {
  margin: 0;
  font-family: 'Segoe UI', sans-serif;
  background: var(--bg-dark);
  color: var(--text);
  overflow-x: hidden;
}

header {
  padding: 20px;
  text-align: center;
  background: var(--bg-light);
  box-shadow: 0 2px 10px rgba(0, 255, 136, 0.2);
}

header h1 {
  margin: 0;
  color: var(--primary);
  text-shadow: var(--glow);
  font-size: 2rem;
  display: inline-flex;
  align-items: center;
  gap: 10px;
}

.filters {
  display: flex;
  justify-content: center;
  gap: 12px;
  padding: 20px;
  flex-wrap: wrap;
}

.filter-btn {
  background: transparent;
  border: 2px solid var(--primary);
  color: var(--primary);
  padding: 8px 16px;
  cursor: pointer;
  border-radius: 6px;
  font-weight: 500;
  transition: 0.3s ease;
}

.filter-btn:hover,
.filter-btn.active {
  background: var(--primary);
  color: var(--bg-dark);
  box-shadow: var(--glow);
}

.gallery {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 15px;
  padding: 20px;
}

.gallery img {
  width: 100%;
  height: 220px;
  object-fit: cover;
  border-radius: 10px;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  cursor: pointer;
}

.gallery img:hover {
  transform: scale(1.05);
  box-shadow: var(--glow);
}

.lightbox {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.85);
  justify-content: center;
  align-items: center;
  z-index: 999;
}

.lightbox.active {
  display: flex;
}

.lightbox img {
  max-width: 90vw;
  max-height: 90vh;
  border-radius: 10px;
  box-shadow: var(--glow);
}

.lightbox .close-btn {
  position: absolute;
  top: 20px;
  right: 30px;
  font-size: 28px;
  color: var(--text);
  cursor: pointer;
}

.lightbox .nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  font-size: 36px;
  color: var(--text);
  cursor: pointer;
  user-select: none;
  padding: 20px;
}

.lightbox .prev {
  left: 20px;
}

.lightbox .next {
  right: 20px;
}

.back-to-top {
  position: fixed;
  bottom: 25px;
  right: 25px;
  padding: 10px 15px;
  background: var(--primary);
  color: var(--bg-dark);
  border: none;
  border-radius: 50%;
  font-size: 20px;
  cursor: pointer;
  display: none;
  box-shadow: var(--glow);
  z-index: 9999;
}

.back-to-top.show {
  display: block;
}

@media (max-width: 600px) {
  .filter-btn {
    padding: 6px 12px;
    font-size: 14px;
  }

  header h1 {
    font-size: 1.5rem;
  }

  .gallery {
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  }

  .gallery img {
    height: 180px;
  }
}