12. What are the differences between classes and IDs in CSS?

• Class: Used for styling groups of elements. Can be used multiple times in a document. Identified by "." (dot).
• ID: Used for styling a unique element. Can be used only once in a document. Identified by "#" (hash).

/* Examples */
.myClass {
    color: red; /* Class - can be used multiple times */
}

#myId {
    color: blue; /* ID - should be unique */
}