Template:Test/styles.css

.infobox-custom {
  border: 1px solid #ccc;
  background-color: #f8f8f8;
  padding: 10px;
}

.test-box {
    border: 2px solid #3366cc;
    background-color: #eef6ff;
    padding: 10px;
    border-radius: 6px;
    font-weight: bold;
}