Including CSS styles inline in an HTML document can be helpful in certain situations, such as when you want to apply a unique style to a single element on a page. You can use the style attribute on the relevant HTML element to include CSS styles inline.

Advantages:

• They allow you to apply unique styles to individual elements, as shown in the example above;
• This can make your HTML markup cleaner and easier to read and can make it easier to maintain and update your styles.

Disadvantages

• It can make your HTML markup more cluttered and difficult to read since the styles are included directly in the HTML elements rather than in a separate stylesheet;
• Using inline styles can make it harder to reuse styles across multiple elements or pages;