* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  background: linear-gradient(135deg, #fffbeb 0%, #fef08a 100%);
  font-family: 'Comic Sans MS', 'Segoe UI', Arial, sans-serif;
  color: #1e3a8a;
  padding: 30px 15px;
  text-align: center;
}

.container {
  max-width: 900px;
  margin: 0 auto;
  background: white;
  padding: 30px;
  border-radius: 30px;
  box-shadow: 0 12px 35px rgba(217, 119, 6, 0.15);
  border: 4px solid #3b82f6;
  position: relative;
  overflow: hidden;
}

.bobo-header {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 15px;
  margin-bottom: 10px;
}

.bobo-avatar {
  width: 80px;
  height: 80px;
  background: #3b82f6;
  border: 5px solid #facc15;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 40px;
  box-shadow: 0 6px 12px rgba(0,0,0,0.1);
  animation: bounce 2s infinite ease-in-out;
}

h1 {
  font-size: 38px;
  margin: 0;
  color: #1d4ed8;
  text-shadow: 2px 2px 0px #fef08a;
}

.subtitle {
  font-size: 18px;
  color: #4b5563;
  margin: 5px 0 30px;
}

.alphabet-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(85px, 1fr));
  gap: 15px;
  margin-bottom: 30px;
}

/* Speelse Letterknoppen (Aangepast voor <button>) */
.letter-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  aspect-ratio: 1 / 1;
  font-size: 36px;
  font-weight: bold;
  font-family: inherit;
  color: white;
  background: #3b82f6;
  border: 4px solid #1d4ed8;
  border-radius: 20px;
  cursor: pointer;
  box-shadow: 0 6px 0px #1d4ed8, 0 10px 15px rgba(0,0,0,0.1);
  transition: all 0.1s ease;
  text-transform: uppercase;
}

.letter-btn:nth-child(4n+1) { background: #3b82f6; border-color: #1d4ed8; box-shadow: 0 6px 0px #1d4ed8; }
.letter-btn:nth-child(4n+2) { background: #facc15; border-color: #ca8a04; box-shadow: 0 6px 0px #ca8a04; color: #1e3a8a; }
.letter-btn:nth-child(4n+3) { background: #ef4444; border-color: #b91c1c; box-shadow: 0 6px 0px #b91c1c; }
.letter-btn:nth-child(4n+4) { background: #22c55e; border-color: #16a34a; box-shadow: 0 6px 0px #16a34a; }

.letter-btn:hover {
  transform: translateY(-2px);
}

.letter-btn:active {
  transform: translateY(6px);
  box-shadow: none;
}

.back-btn {
  display: inline-block;
  padding: 12px 28px;
  background: #1e293b;
  color: white;
  text-decoration: none;
  font-weight: bold;
  font-size: 16px;
  border-radius: 15px;
  transition: background 0.2s;
  box-shadow: 0 4px 10px rgba(0,0,0,0.1);
}

.back-btn:hover {
  background: #334155;
}

/* Video Pop-up Overlay Stijlen */
.video-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(0, 0, 0, 0.85);
  z-index: 9999;
  display: flex;
  align-items: center;
  justify-content: center;
}

.video-container {
  position: relative;
  width: 90%;
  height: 80vh;
  max-width: 1000px;
}

.video-container iframe {
  width: 100%;
  height: 100%;
  border: none;
  border-radius: 15px;
  background: black;
}

.close-video-btn {
  position: absolute;
  top: -50px;
  right: 0;
  background: #ef4444;
  color: white;
  border: none;
  padding: 8px 18px;
  font-size: 18px;
  font-weight: bold;
  border-radius: 10px;
  cursor: pointer;
  box-shadow: 0 4px 10px rgba(0,0,0,0.3);
}

@keyframes bounce {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  50% { transform: translateY(-10px) rotate(5deg); }
}

@media (max-width: 500px) {
  .container { padding: 20px 10px; border-width: 3px; }
  h1 { font-size: 28px; }
  .bobo-avatar { width: 60px; height: 60px; font-size: 30px; }
  .alphabet-grid { grid-template-columns: repeat(4, 1fr); gap: 10px; }
  .letter-btn { font-size: 28px; border-width: 3px; box-shadow: 0 4px 0px rgba(0,0,0,0.2); }
  .video-container { height: 60vh; }
  .close-video-btn { top: -45px; font-size: 16px; }
}