Shadow DOM is a web technology that allows developers to encapsulate the structure, styles, and behavior of a component, isolating it from the main document's DOM (Document Object Model). 

This encapsulation allows for greater modularity and prevents unintentional interactions or style conflicts between components.

Key features and benefits of Shadow DOM include:

1. Encapsulation: With Shadow DOM, the internal structure, styles, and behaviors of a component are kept separate from the main document. 

This separation ensures that the component's internals are protected from external changes and vice versa.

2. Scoped Styles: Styles defined inside a shadow root apply only to the elements within that shadow tree.

 They don't leak out to the parent document, nor do external styles affect the shadow tree's content. 

 This prevents unwanted style interactions.

3. Composition: Using slots, a feature in Shadow DOM, you can define placeholders where users of your component can insert content. 

This allows for flexible composition while keeping the internals encapsulated.

4. Isolation: The DOM inside the shadow root is separate from the main page's DOM. 

This means selectors from outside the shadow root can't target elements inside of it, and vice versa.