3. What is a selector in CSS?

A selector in CSS is a pattern used to select the HTML elements you want to style. Selections can be simple, like element names, classes, or IDs, or more advanced, like compound selectors.

/* Examples */
p {
    color: blue;
}

.myClass {
    font-size: 20px;
}

#myId {
    background-color: yellow;
}