*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  background: #1a1a1a;
  color: #e0e0e0;
  font-family: system-ui, -apple-system, sans-serif;
}

.header {
  padding: 0.75rem 1rem;
  text-align: center;
  background: #252525;
  border-bottom: 1px solid #333;
  position: sticky;
  top: 0;
  z-index: 10;
}

.header h1 {
  margin: 0 0 0.25rem;
  font-size: 1.25rem;
  font-weight: 600;
}

.hint {
  margin: 0;
  font-size: 0.8rem;
  opacity: 0.85;
}

.gallery {
  display: grid;
  grid-template-columns: repeat(10, 1fr);
  gap: 4px;
  padding: 8px;
  max-width: 100%;
  margin: 0 auto;
  outline: none;
}

.gallery:focus {
  outline: none;
}

.gallery-item {
  aspect-ratio: 1;
  overflow: hidden;
  background: #2a2a2a;
}

.gallery-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  vertical-align: middle;
}

@media (max-width: 1200px) {
  .gallery {
    grid-template-columns: repeat(8, 1fr);
  }
}

@media (max-width: 768px) {
  .gallery {
    grid-template-columns: repeat(5, 1fr);
    gap: 3px;
    padding: 6px;
  }
}

@media (max-width: 480px) {
  .gallery {
    grid-template-columns: repeat(4, 1fr);
  }
}

.footer {
  padding: 1rem;
  text-align: center;
  font-size: 0.85rem;
  background: #252525;
  border-top: 1px solid #333;
}

.footer a {
  color: #e0e0e0;
  text-decoration: none;
}

.footer a:hover {
  text-decoration: underline;
}

.footer .chief {
  display: block;
  margin-top: 0.5rem;
  opacity: 0.9;
}