CSS basics · Lesson 2 of 12 · 7 minutes

CSS basics: Class selectors

A class selector targets an intentional reusable hook rather than every element of a type.

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Your objectives

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1
Build class selectors
Build this first target: .notice with color: #164e45. Keep the selector relationships intact and inspect the preview.
Hint & worked example
A class selector targets an intentional reusable hook rather than every element of a type.
The requested selectors and declarations exist outside comments.
```
.notice { color: #164e45; }
```
Common mistake to avoid: If the page fits one desktop viewport, no narrower viewport needs checking.
2
Extend the class selectors example
Extend your file to include: .notice with color: #164e45; .notice with padding: 1rem. Keep the selector relationships intact and inspect the preview.
Hint & worked example
A class selector targets an intentional reusable hook rather than every element of a type.
The requested selectors and declarations exist outside comments.
```
.notice { color: #164e45; }
.notice { padding: 1rem; }
```
Common mistake to avoid: Hiding all overflow always makes content accessible.
3
Verify the complete class selectors pattern
Finish the pattern with: .notice with color: #164e45; .notice with padding: 1rem; .notice with border: 1px solid #658b84. Keep the selector relationships intact and inspect the preview.
Hint & worked example
A class selector targets an intentional reusable hook rather than every element of a type.
The requested selectors and declarations exist outside comments.
```
.notice { color: #164e45; }
.notice { padding: 1rem; }
.notice { border: 1px solid #658b84; }
```
Common mistake to avoid: If the page fits one desktop viewport, no narrower viewport needs checking.

Understand the pattern

A class selector targets an intentional reusable hook rather than every element of a type.

Misconceptions to reject

If the page fits one desktop viewport, no narrower viewport needs checking.
Hiding all overflow always makes content accessible.

The preview is a sanitized subset, not a full browser compatibility test.

Worked example and expected result

.notice { color: #164e45; }
.notice { padding: 1rem; }
.notice { border: 1px solid #658b84; }

A class selector targets an intentional reusable hook rather than every element of a type.

Try a variation

Adapt the final example to a different project name while retaining its structure and relationships. A different context still needs a real browser and accessibility check.

Explain it

Which statement correctly explains class selectors?A class selector targets an intentional reusable hook rather than every element of a type.If the page fits one desktop viewport, no narrower viewport needs checking.Hiding all overflow always makes content accessible.

Apply it elsewhere

You reuse class selectors in a different project. What must still be verified?Nothing; passing a single exercise guarantees every future use.Only whether the source code has the same number of lines.The resulting layout, focus behavior, and readability at the target viewport sizes.

Keep the momentum.

Complete the lab, then explain and apply the pattern.

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MDN: CSS styling