:root {
  --bg-color: #f9f9f9;
  --text-color: #222;
  --link-color: #007acc;
}

body.dark {
  --bg-color: #111;
  --text-color: #ddd;
  --link-color: #66ccff;
}

body {
  margin: 0;
  font-family: "Segoe UI", sans-serif;
  background: var(--bg-color);
  color: var(--text-color);
  transition: background 0.3s, color 0.3s;
  overflow-x: hidden;
}

.header {
  padding: 16px;
  text-align: center;
}

.controls button {
  margin: 0 8px;
  padding: 6px 12px;
  font-size: 14px;
  cursor: pointer;
}

.container {
  display: flex;
  flex-direction: column;
  align-items: center;
  max-width: 1920px;
  margin: auto;
}

#mainImage {
  max-width: 100%;
  max-height: 1080px;
  transition: transform 0.3s;
  cursor: zoom-in;
  border-radius: 12px;
}

#mainImage.zoomed {
  transform: scale(1.2);
  cursor: zoom-out;
}

.hint {
  margin-top: 10px;
  font-size: 14px;
  opacity: 0.8;
}

footer {
  text-align: center;
  padding: 16px;
  font-size: 14px;
  opacity: 0.7;
}

a {
  color: var(--link-color);
}

.thumbnails {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  margin-top: 16px;
}

.thumbnails img {
  width: 100px;
  height: 70px;
  object-fit: cover;
  object-position: center;
  cursor: pointer;
  border: 2px solid transparent;
  border-radius: 6px;
  transition: transform 0.2s, border-color 0.3s;
}

.thumbnails img:hover {
  transform: scale(1.05);
  border-color: var(--link-color);
}

.thumbnails img.active {
  border-color: var(--link-color);
  box-shadow: 0 0 8px var(--link-color);
  transform: scale(1.05);
}

canvas#background {
  position: fixed;
  top: 0;
  left: 0;
  z-index: -1;
}