Tidle sign

General sibling combinator

by dceast

HTML

<div class="demo">
    <input type="checkbox" class="check"><br>
    <label class="content">.content </label><br>
    <input type="checkbox" class="check"><br>
    <label id="content">#content</label>
</div>

CSS

.demo {
    margin-bottom: 10px;
    border: 1px dotted;
}
.check:checked ~ .content {
    background: yellow;
}

.check:checked ~ #content {
    background: yellow;
}