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

body {
  margin: 0;
  font-family: sans-serif;
}

header {
  background-color: #333;
  color: white;
  padding: 16px;
  text-align: center;
}

nav {
  background-color: #222;
  position: sticky;
  top: 0;
  z-index: 10;
}

nav ul {
  list-style: none;
  margin: 0;
  padding: 8px 16px;
  display: flex;
  gap: 16px;
}

nav a {
  color: white;
  text-decoration: none;
}

#menu-toggle {
  display: none;
}

.gallery {
  padding: 16px;
}

.gallery::after {
  content: "";
  display: block;
  clear: both;
}

.photo-item {
  float: left;
  width: 30%;
  margin: 1.5%;
  position: relative;
}

.photo-item img {
  width: 100%;
  display: block;
}

.photo-caption {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  margin: 0;
  background: rgba(0,0,0,0.5);
  color: white;
  text-align: center;
  padding: 4px 0;
}

footer {
  background-color: #333;
  color: white;
  text-align: center;
  padding: 12px;
  clear: both;
}

@media (max-width: 768px) {
  .photo-item {
    width: 46%;
  }
}

@media (max-width: 480px) {
  .photo-item {
    width: 96%;
    float: none;
  }
  #nav-links {
    display: none;
  }
  #nav-links.open {
    display: block;
  }
  #menu-toggle {
    display: block;
    cursor: pointer;
    background: none;
    border: none;
    color: white;
    font-size: 1.2rem;
    padding: 8px 16px;
  }
}