.responsive-video {
  position: relative;
  padding-bottom: 56.25%;
  height: 0;
  overflow: hidden;
}
.responsive-video iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}
.n3t-placeholder {
  background: #f9f9f9;
  border: 2px dashed #ccc;
  border-radius: 12px;
  padding: 2rem 1rem;
  text-align: center;
}
.n3t-placeholder p {
  font-size: 1.1rem;
  margin-bottom: 1rem;
}
.n3t-placeholder .btn {
  background-color: var(--cassiopeia-color-primary, #0d6efd);
  color: #fff;
  border: none;
  padding: 0.6rem 1.2rem;
  border-radius: 6px;
  font-weight: 600;
  cursor: pointer;
}