body {
  margin: 0;
  font-family: 'Roboto Slab', serif;
  background: #f9f9f9;
  color: #333;
  text-align: center;
}

header {
  padding: 2rem;
  background: #fff;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.logo { max-width: 180px; }

.description {
  max-width: 700px;
  margin: 1rem auto;
  line-height: 1.5;
}

#filters {
  display: flex;
  justify-content: center;
  gap: 1rem;
  flex-wrap: wrap;
  margin-top: 1rem;
}

#videos {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px,1fr));
  gap: 1rem;
  padding: 1rem;
}

.card {
  background: #fff;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  padding: 1rem;
  display: flex;
  flex-direction: column;
  align-items: stretch;
}

.card iframe {
  width: 100%;
  aspect-ratio: 16/9;
  border-radius: 4px;
  background: #000;
}

.card h3 {
  margin: 0.5rem 0;
}

.card .level {
  font-size: 0.9rem;
  color: #666;
}

.card details {
  margin: 0.5rem 0 1rem;
}

.controls {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
}

.controls select,
.controls button {
  padding: 0.4rem 0.8rem;
  border: 1px solid #ccc;
  border-radius: 4px;
  font-size: 0.9rem;
  cursor: pointer;
}

.controls button {
  background: #007BFF;
  color: #fff;
  border-color: #007BFF;
  transition: background 0.2s;
}

.controls button:hover {
  background: #0056b3;
}