Position absolute in CSS - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding the effect of position: absolute

What happens to an element with position: absolute inside a container without any positioning?

A It becomes fixed to the viewport and does not move when scrolling.

B It stays in the normal document flow and pushes other elements down.

C It positions itself relative to the nearest positioned ancestor or the viewport if none exists.

D It disappears from the page and is not visible.

💡 Hint

Think about what happens if no parent has position set.

An element with position: absolute is taken out of the normal flow and positioned relative to the nearest ancestor that has a positioning other than static. If no such ancestor exists, it positions relative to the initial containing block (usually the viewport).

📝 Syntax

intermediate

CSS positioning syntax and effect

Given this CSS, what will be the position of the red box relative to the blue container?

.container { position: relative; width: 200px; height: 200px; background: blue; }
.box { position: absolute; top: 20px; left: 30px; width: 50px; height: 50px; background: red; }

A The red box will be hidden behind the blue container.

B The red box will be 20px from the top and 30px from the left inside the blue container.

C The red box will be centered inside the blue container.

D The red box will be 20px from the top and 30px from the left of the entire page.

💡 Hint

Check the container's position property.

Because the container has position: relative, the absolutely positioned red box uses it as the reference point. So top: 20px and left: 30px place the red box inside the blue container at those distances.

❓ rendering

advanced

Visual stacking order with position: absolute

Consider this HTML and CSS:

<div class='parent'><div class='child1'>A</div><div class='child2'>B</div></div>
.parent { position: relative; width: 150px; height: 150px; background: lightgray; }
.child1 { position: absolute; top: 20px; left: 20px; width: 100px; height: 100px; background: red; z-index: 1; }
.child2 { position: absolute; top: 50px; left: 50px; width: 100px; height: 100px; background: blue; }

Which box will appear on top visually?

A The red box (child1) will appear on top because it has a higher z-index.

B Both boxes will appear side by side without overlapping.

C The blue box (child2) will appear on top because it is declared later in the HTML.

D The red box will be hidden behind the blue box because it has a lower z-index.

💡 Hint

Remember how z-index controls stacking order.

The red box has z-index: 1 which is higher than the default z-index: auto of the blue box. This means the red box will be drawn on top of the blue box where they overlap.

❓ selector

advanced

Selecting absolutely positioned elements with CSS

Which CSS selector will select only the elements that have position: absolute applied?

A *[style*='position: absolute']

B .absolute

C :is([style*='position: absolute'])

D :where([style*='position: absolute'])

💡 Hint

Think about how to select elements by inline style attribute.

Only option A uses an attribute selector to find elements with inline styles containing position: absolute. The others are pseudo-class selectors that do not select by style attribute.

❓ accessibility

expert

Accessibility considerations for absolutely positioned elements

When using position: absolute for UI elements like modals or tooltips, what is the most important accessibility practice?

A Avoid using semantic HTML elements inside absolutely positioned containers.

B Hide the element from screen readers by using <code>aria-hidden='true'</code> always.

C Use <code>position: fixed</code> instead to avoid accessibility issues.

D Ensure the element is reachable and announced by screen readers using ARIA roles and keyboard focus management.

💡 Hint

Think about users who rely on keyboard and screen readers.

Absolutely positioned UI elements like modals must be accessible. This means managing keyboard focus so users can tab into and out of them, and using ARIA roles (like role='dialog') so screen readers announce them properly.