.expandable::after {
    content: " (Click to expand)";
    font-size: 0.7em;
    color: gray;
}

input.expandable-checkbox {
  display: none;
}

input.expandable-checkbox + .expandable-content {
    display:none;
}

input.expandable-checkbox:checked + .expandable-content {
    display:block;
}