CSS Performance — Quiz

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Question 1

Why does the size of your CSS file affect how fast users see the page?

A It doesn't

B CSS is render-blocking — the browser waits for it before showing the page

C CSS runs after the page is visible

D Only images block rendering

Question 2

Which properties are cheap to animate smoothly?

A width and height

B transform and opacity

C top and margin

D display and float

Question 3

What is 'layout thrash'?

A A type of animation

B Forcing the browser to re-calculate positions repeatedly, causing stutter

C A CSS framework

D A fast-loading technique

Question 4

How do you prevent the page jumping as images load?

A Use larger images

B Set width and height so space is reserved

C Remove all images

D Animate the images

Question 5

What is 'critical CSS'?

A CSS that contains errors

B Inlining the small amount of CSS needed for the visible part so it paints almost instantly

C The largest stylesheet

D CSS only for mobile