.demo-and {
  padding: 15px;
  margin: 10px 0;
  border: 2px solid #ddd;
  border-radius: 5px;
  background: #fff;
}

@media screen and (min-width: 600px) and (max-width: 900px) {
  .demo-and {
    background-color: #e7f3ff;
    border-color: #007bff;
  }
  .demo-and::before {
    content: "✓ AND condition met: Screen width between 600px-900px";
    display: block;
    color: #007bff;
    font-weight: bold;
    margin-bottom: 10px;
  }
}