Shadow Boundary

Hands-on practice for this lecture. Work through the exercises and quizzes to reinforce what you've learned.

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Exercise 1 of 1

Shadow DOM: Does This CSS Reach?

Five CSS rules — decide which ones can style an element inside a shadow root, and which stop at the boundary.

Does this CSS reach the shadow DOM?

For each rule, pick whether it styles the target element or is blocked at the boundary.

user-badge .avatar { border-radius: 50%; }

.avatar is a div inside the component's shadow root

user-badge span { color: rgb(250,199,117); }

The <span> is slotted content you placed between the component's tags

user-badge { --badge-color: rgb(93,202,165); }

The component uses var(--badge-color) in its internal styles

user-badge * { box-sizing: border-box; }

The * targets all descendants including shadow DOM internals

body { font-family: "Inter", sans-serif; }

The component has no font-family set inside its shadow root

The rule: if you wrote it, you can style it. CSS custom properties (--var) and inheritable properties like font-family are the two exceptions that always cross the boundary.

Practice: Shadow Boundary — Interactive Exercises | Durgesh Rai