body {
  margin: 0;
  font-family: Arial, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  transition: background-color 0.3s, color 0.3s;
}
:root {
  --bg-color: #ffffff;
  --text-color: #000000;
  --header-footer-bg: #f8f8f8;
  --button-bg: #007bff;
  --button-text: #ffffff;
}
[data-theme="dark"] {
  --bg-color: #121212;
  --text-color: #ffffff;
  --header-footer-bg: #1e1e1e;
  --button-bg: #4caf50;
  --button-text: #ffffff;
}
header, footer {
  background-color: var(--header-footer-bg);
  text-align: center;
  padding: 10px 20px;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}
header h1, footer p { margin: 0; }
header h1 a { color: blueviolet; }
header h1 a:hover { color: chocolate; }
footer { margin-top: 20px; }
footer a { text-decoration: none; color: unset; }
main { padding: 20px; text-align: center; }
.form-container {
  display: flex;
  justify-content: center;
  margin: 10px;
}
input[type="text"] {
  padding: 10px;
  font-size: 16px;
  border: 1px solid #ccc;
  border-radius: 5px 0 0 5px;
  width: 300px;
}
button {
  padding: 10px 15px;
  font-size: 16px;
  background-color: var(--button-bg);
  color: var(--button-text);
  border: none;
  cursor: pointer;
  border-radius: 0 5px 5px 0;
}
button:hover { opacity: 0.9; }
#imageGrid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
  gap: 10px;
}
.image-container {
  position: relative;
  width: 100%;
  height: 250px;
  overflow: hidden;
  border-radius: 5px;
}
.image-container img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  cursor: default;
}
.download-btn {
  position: absolute;
  top: 10px;
  right: 10px;
  background-color: #006bca;
  color: var(--button-text);
  border: none;
  padding: 6px 8px;
  font-size: 14px;
  cursor: pointer;
  border-radius: 50%;
  opacity: 0.5;
}
.download-btn:hover { opacity: 0.8; }
.overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.8);
  display: none;
  justify-content: center;
  align-items: center;
  z-index: 1000;
  opacity: 0;
  transition: opacity 0.3s ease-in-out;
}
.overlay.visible { display: flex; opacity: 1; }
.overlay img {
  max-width: 90%;
  max-height: 90%;
  border-radius: 10px;
}
.overlay .close-btn {
  position: absolute;
  background-color: var(--button-bg);
  color: var(--button-text);
  border: none;
  padding: 10px;
  font-size: 16px;
  cursor: pointer;
  border-radius: 5px;
  top: 20px;
  right: 20px;
}
.theme-toggle {
  position: absolute;
  top: 12px;
  right: 12px;
  padding: 10px;
  background-color: var(--button-bg);
  color: var(--button-text);
  border: none;
  cursor: pointer;
  border-radius: 50%;
}
.scroll-top {
  position: fixed;
  bottom: 20px;
  left: 20px;
  display: none;
  background-color: var(--button-bg);
  color: var(--button-text);
  border: none;
  padding: 10px 13px;
  cursor: pointer;
  border-radius: 50%;
  z-index: 1000;
}
.scroll-top.show { display: block; }
@media (max-width: 600px) { .theme-toggle { top: 7px; right: 8px; } }