First-child and last-child in CSS - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ selector

intermediate

Identify the color of the first list item

Given the CSS below, what color will the first

inside the

have when rendered in the browser?

CSS

ul li:first-child { color: red; }
ul li:last-child { color: blue; }

<ul>
  <li>Apple</li>
  <li>Banana</li>
  <li>Cherry</li>
</ul>

A Green

B Blue

C Red

D Black (default color)

💡 Hint

Remember, :first-child targets the very first child element of its parent.

The selector ul li:first-child targets the first

inside the

. It sets its color to red. So the first list item 'Apple' will be red.

❓ selector

intermediate

Which element is selected by :last-child?

Consider the HTML and CSS below. Which element will have a blue background color?

CSS

div p:last-child { background-color: blue; }

<div>
  <p>Paragraph 1</p>
  <p>Paragraph 2</p>
  <span>Span element</span>
</div>

A Paragraph 2

B No element is selected

C Span element

D Paragraph 1

💡 Hint

:last-child selects the last child of the parent, regardless of type.

The last child inside the div is the span element, not a p. Since the selector is div p:last-child, it looks for a p that is the last child. There is none, so no p is selected. The span is last child but not a p.

🧠 Conceptual

advanced

Difference between :first-child and :first-of-type

Which statement correctly explains the difference between :first-child and :first-of-type selectors?

A <code>:first-child</code> selects the last child; <code>:first-of-type</code> selects the first child.

B <code>:first-child</code> selects the first element of its type; <code>:first-of-type</code> selects the first child of the parent.

C <code>:first-child</code> and <code>:first-of-type</code> select the same elements always.

D <code>:first-child</code> selects the first child of its parent regardless of type; <code>:first-of-type</code> selects the first sibling of its type.

💡 Hint

Think about whether the selector cares about the element type or just position.

:first-child matches an element only if it is the very first child of its parent, no matter what type it is. :first-of-type matches the first sibling of its own type, even if it is not the first child overall.

❓ layout

advanced

Styling first and last items in a flex container

You have a horizontal menu using flexbox. You want the first menu item to have extra left padding and the last menu item to have extra right padding. Which CSS will achieve this?

CSS

nav ul {
  display: flex;
  list-style: none;
  padding: 0;
  margin: 0;
}

nav ul li:first-child {
  padding-left: 2rem;
}

nav ul li:last-child {
  padding-right: 2rem;
}

A Use :first-child and :last-child selectors on the <li> elements inside the flex container.

B Use :first-of-type and :last-of-type selectors on the <ul> element.

C Add padding to the <nav> element instead of the <li> elements.

D Use JavaScript to add classes to first and last items and style those classes.

💡 Hint

Think about which elements are the flex items and how to target them with CSS selectors.

The flex container is the ul. Its direct children li are flex items. Using :first-child and :last-child on li targets the first and last menu items for styling.

❓ accessibility

expert

Accessibility impact of styling only first-child and last-child

If you style only the first and last items in a navigation list with different colors using :first-child and :last-child, what accessibility concern might arise?

A Users relying on keyboard navigation might not perceive the difference if color contrast is insufficient or color is the only cue.

B The first and last items will not be focusable by keyboard.

C The page will fail HTML validation due to use of :first-child and :last-child selectors.

D Screen readers will ignore the first and last items because of the CSS selectors.

💡 Hint

Think about how color-only styling affects users with visual impairments or color blindness.

Using color alone to differentiate elements can cause issues for users with color blindness or low vision. Keyboard users might not notice visual differences if focus styles are missing. It's important to ensure sufficient contrast and provide multiple cues beyond color.

Practice

1. What does the CSS selector :first-child do?

easy

A. It selects the last child element inside its parent.

B. It selects the first child element inside its parent.

C. It selects all child elements except the first.

D. It selects only the parent element.

Solution

1. Step 1: Understand the selector purpose

   The :first-child selector targets only the very first child element within a parent container.

2. Step 2: Compare with other options

   :last-child targets the last child, others do not match the description.

3. Final Answer:

   It selects the first child element inside its parent. -> Option B

4. Quick Check:

   :first-child = first child selected [OK]

Hint: First-child always picks the very first element inside a parent [OK]

Common Mistakes:

• Confusing :first-child with :last-child
• Thinking it selects all children
• Assuming it selects the parent

2. Which of the following is the correct CSS syntax to style the last child of a <ul> list?

easy

A. ul > li:last-child { color: red; }

B. ul:last-child { color: red; }

C. ul li:first-child { color: red; }

D. ul:last-child li { color: red; }

Solution

1. Step 1: Identify the target element

   The goal is to style the last <li> inside a <ul>, so the selector must target li elements that are last children.

2. Step 2: Check selector correctness

   ul > li:last-child correctly selects the last li directly inside ul. Other options either select the wrong element or use incorrect syntax.

3. Final Answer:

   ul > li:last-child { color: red; } -> Option A

4. Quick Check:

   Correct syntax for last child inside ul = ul > li:last-child { color: red; } [OK]

Hint: Use parent > child:last-child to style last child only [OK]

Common Mistakes:

• Using :last-child on the parent instead of the child
• Confusing :first-child with :last-child
• Missing the direct child combinator >

3. Given this HTML:

<ul>
  <li>Apple</li>
  <li>Banana</li>
  <li>Cherry</li>
</ul>

And CSS:

li:first-child { color: blue; }
li:last-child { color: green; }

What color will the text "Banana" have when rendered?

medium

A. Blue

B. Green

C. Black (default)

D. Both blue and green

Solution

1. Step 1: Identify which elements get styled

   li:first-child styles the first li (Apple), li:last-child styles the last li (Cherry).

2. Step 2: Determine Banana's position

   Banana is the second li, so it is neither first nor last child, so no color styles apply.

3. Final Answer:

   Black (default) -> Option C

4. Quick Check:

   Banana is middle child, no color applied [OK]

Hint: Only first or last child get styles, middle ones stay default [OK]

Common Mistakes:

• Assuming all list items get styled
• Confusing order of children
• Thinking styles cascade to siblings

4. This CSS code is intended to color the first and last paragraphs inside a <section> green and blue respectively:

section p:first-child { color: green; }
section p:last-child { color: blue; }

But only the first paragraph turns green, the last paragraph stays black. Why?

medium

A. Because the colors green and blue are invalid.

B. Because the CSS syntax is incorrect.

C. Because section cannot contain paragraphs.

D. Because p elements are not the first or last child of section.

Solution

1. Step 1: Understand :first-child and :last-child context

   These selectors check if the element is the very first or last child of its parent, regardless of type.

2. Step 2: Check if p is first or last child

   If other elements (like headings or divs) come before or after the p, then p is not first or last child, so styles won't apply.

3. Final Answer:

   Because p elements are not the first or last child of section. -> Option D

4. Quick Check:

   :first-child and :last-child depend on element position, not type [OK]

Hint: Check if element is truly first/last child, not just first/last of type [OK]

Common Mistakes:

• Assuming :first-child means first of type
• Ignoring other sibling elements
• Thinking syntax is wrong when it's position issue

5. You want to style the first and last <li> elements inside every <ul> differently, but only if the <li> is also the first or last child of its parent. Which CSS selectors correctly achieve this?

hard

A. ul > li:first-child { font-weight: bold; } and ul > li:last-child { font-style: italic; }

B. ul:first-child li { font-weight: bold; } and ul:last-child li { font-style: italic; }

C. ul li:first-child { font-weight: bold; } and ul li:last-child { font-style: italic; }

D. ul li:first-of-type { font-weight: bold; } and ul li:last-of-type { font-style: italic; }

Solution

1. Step 1: Understand the requirement

   We want to style only li elements that are the first or last child of their ul parent.

2. Step 2: Choose selectors that target direct children and correct position

   ul > li:first-child and ul > li:last-child select li elements that are direct children and first or last child respectively. This matches the requirement exactly.

3. Step 3: Evaluate other options

   ul li:first-child { font-weight: bold; } and ul li:last-child { font-style: italic; } misses the direct child combinator, which can cause incorrect matches if nested lists exist. ul:first-child li { font-weight: bold; } and ul:last-child li { font-style: italic; } incorrectly applies :first-child to ul. ul li:first-of-type { font-weight: bold; } and ul li:last-of-type { font-style: italic; } uses :first-of-type which selects first li regardless of position among siblings.

4. Final Answer:

   ul > li:first-child { font-weight: bold; } and ul > li:last-child { font-style: italic; } -> Option A

5. Quick Check:

   Direct child + :first-child and :last-child = ul > li:first-child { font-weight: bold; } and ul > li:last-child { font-style: italic; } [OK]

Hint: Use direct child combinator > with :first-child and :last-child [OK]

Common Mistakes:

• Omitting > combinator causing wrong matches
• Confusing :first-child with :first-of-type
• Applying selectors to wrong parent element