.ad-slot {
  width: 100%;
  min-height: 100px;
  text-align: center;
}

.ad-placeholder {
  width: 100%;
  min-height: 250px;

  display: flex;
  align-items: center;
  justify-content: center;

  border: 1px dashed #aaa;
  box-sizing: border-box;

  font-size: 14px;
  color: #888;
}