/* Fade-in-up animation */
@keyframes fadeInUp {
  0% {
    opacity: 0;
    transform: translateY(20px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}

.fade-in-up {
  animation: fadeInUp 0.8s ease-out forwards;
}

/* Glass card for dark theme */
.glass-card {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  border-radius: 1rem;
  padding: 2rem;
  box-shadow: 0 0 30px rgba(255, 255, 255, 0.1);
}

/* Fade-in animation for glass cards */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.animate-fadeIn {
  animation: fadeIn 1s ease forwards;
  opacity: 0;
}

/* Achtergrond pseudo-element */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
  filter: grayscale(100%) blur(4px) brightness(0.4);
  z-index: -1;
  opacity: 0.9;
  transition: background-image 0.8s ease-in-out;
}

/* Fullscreen layout for categories */
#categories-container {
  width: 100%;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 2rem;
}

/* Category cards */
#categories-container .category-card {
  background: rgba(255,255,255,0.03);
  border: 1px solid rgba(255,255,255,0.12);
  border-radius: 12px;
  padding: 2rem;
  cursor: pointer;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  backdrop-filter: blur(8px);
  box-shadow: 0 10px 30px rgba(255,255,255,0.06);
}

#categories-container .category-card:hover {
  transform: translateY(-5px) scale(1.02);
  box-shadow: 0 10px 20px rgba(255, 255, 255, 0.1);
  border-color: #555;
}

/* Category text */
#categories-container .category-card h2 {
  font-size: 1.5rem;
  font-weight: bold;
  margin-top: 1rem;
  color: #fff;
}

#categories-container .category-card p {
  color: #aaa;
  margin-top: 0.5rem;
  font-size: 1rem;
}

/* Scrollbar */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-thumb {
  background: #444;
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: #666;
}

/* Fade-in animation for main container */
@keyframes fade-in {
  0% { opacity: 0; transform: translateY(10px); }
  100% { opacity: 1; transform: translateY(0); }
}

.animate-fade-in {
  animation: fade-in 1s ease-out;
}

#boekkaftenContainer {
  width: 100%;
  max-width: 1400px;
  gap: 3rem; /* extra ruimte tussen kaften */
}

/* Kaft kaarten */
.boekkaft-card {
  background: rgba(255,255,255,0.03);
  border: 1px solid rgba(255,255,255,0.12);
  backdrop-filter: blur(8px);
  display: flex;
  justify-content: center;
  align-items: center;
  border-radius: 1rem;
  overflow: hidden;
  padding: 1rem;
  box-shadow: 0 8px 30px rgba(255,255,255,0.06);
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

/* Afbeeldingen */
.boekkaft-card img {
  display: block;
  max-width: 100%;
  max-height: 550px;
  height: auto;
  width: auto;
  object-fit: contain;
  transition: transform 0.3s ease, opacity 0.25s ease;
  opacity: 1;
  border-radius: 0.5rem;
}

/* Archiefstijl */
.archief-card img {
  transition: transform 0.3s ease;
}

.archief-card:hover img {
  transform: scale(1.05);
}

/* ======================================= */
/* Stijl voor categorie knoppen */
/* ======================================= */

#categories-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 2rem;
  width: 100%;
  max-width: 900px;
  margin: 0 auto;
}

.category-btn {
  display: block;
  background-color: #1e1e1e;
  border: 2px solid #fff;
  border-radius: 1rem;
  padding: 1.5rem;
  text-align: center;
  font-size: 1.25rem;
  font-weight: 600;
  color: #fff;
  text-decoration: none;
  transition: all 0.3s ease;
  box-shadow: 0 5px 15px rgba(0,0,0,0.3);
}

.category-btn:hover {
  background-color: #fff;
  color: #121212;
  transform: translateY(-3px);
  box-shadow: 0 8px 20px rgba(255,255,255,0.3);
}