.poster-detail {
  min-height: 80vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
.poster-full {
  max-height: 80vh;
  border-radius: 12px;
  box-shadow: 0 6px 25px rgba(0,0,0,0.4);
}
.btn-back {
  background: #334155;
  color: #fff;
  border-radius: 8px;
  padding: 6px 14px;
  font-weight: 500;
  transition: all 0.2s;
}
.btn-back:hover {
  background: #64748b;
  color: #fff;
}

header {
  backdrop-filter: blur(10px);
}