main {
  flex-grow: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 4rem 2rem;
  gap: 3rem;
  width: 100%;
}

img {
  width: 80%;
  border-radius: 20px;
  display: block;
  margin: 10px auto;
}

#additional-content {
  width: 100%;
  max-width: 900px;
  text-align: center;
}

#additional-content h1 {
  font-size: 2.8rem;
  margin-bottom: 0.5rem;
  color: var(--color-text-primary);
}

#additional-content p {
  font-size: 1.1rem;
  color: var(--color-text-subtle);
  margin-bottom: 3rem;
}

.category {
  margin-bottom: 3rem;
  text-align: left;
}

.category h2 {
  font-size: 2rem;
  color: var(--color-text-secondary);
  border-bottom: 2px solid var(--color-accent);
  padding-bottom: 0.5rem;
  margin-bottom: 1.5rem;
}

.materials-container {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
  align-items: stretch;
}

.material-card {
  background-color: var(--color-background-secondary);
  border-radius: 8px;
  padding: 1.5rem;
  border: 1px solid var(--color-text-subtle);
  transition: transform 0.3s ease, box-shadow 0.3s ease;
  display: flex;
  flex-direction: column;
  text-decoration: none;
  color: inherit;
  cursor: pointer;
  height: 100%;
}

.material-card img {
  width: 100%;
  height: 200px;
  object-fit: contain;
  margin: 0 auto 1.5rem auto;
  border-radius: 4px;
  display: block;
}

.material-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.material-card h3 {
  font-size: 1.4rem;
  color: var(--color-text-primary);
  margin-bottom: 0.75rem;
  line-height: 1.3;
}

.material-card p {
  font-size: 1rem;
  color: var(--color-text-subtle);
  margin-bottom: 0;
  flex-grow: 1;
}

.video-card-link {
  display: block;
  text-decoration: none;
  background-color: var(--color-background-secondary);
  border-radius: 8px;
  border: 1px solid var(--color-border);
  overflow: hidden;
  transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.video-card-link figure {
  margin: 0;
}

.video-card-link:hover {
  transform: translateY(-5px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

.video-thumbnail {
  position: relative;
  width: 100%;
  background-color: #000;
}

.video-thumbnail img {
  display: block;
  width: 100%;
  height: auto;
  opacity: 0.9;
  transition: opacity 0.3s ease;
}

.video-card-link:hover .video-thumbnail img {
  opacity: 1;
}

.video-card-link.video-iframe {
  position: relative;
  padding-bottom: 56.25%;
  height: 0;
  overflow: hidden;
  max-width: 100%;
}

.video-card-link.video-iframe iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.play-icon {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 70px;
  height: 70px;
  background-color: rgba(0, 0, 0, 0.7);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  pointer-events: none;
  transition: background-color 0.3s ease;
}

.play-icon svg {
  margin-left: 4px;
}

.video-card-link:hover .play-icon {
  background-color: var(--color-accent);
}

figcaption.video-description {
  padding: 1.5rem;
}

figcaption.video-description h3 {
  font-size: 1.4rem;
  color: var(--color-text-primary);
  margin-bottom: 0.5rem;
}

figcaption.video-description p {
  font-size: 1rem;
  color: var(--color-text-subtle);
  margin-bottom: 0;
}