Line height in CSS - Mini Project: Build & Apply

Adjusting Line Height for Better Readability

📖 Scenario: You are creating a simple webpage with a paragraph of text. The text looks cramped and hard to read. You want to improve the spacing between lines to make it easier on the eyes.

🎯 Goal: Build a webpage with a paragraph and use CSS to set the line height to improve readability.

📋 What You'll Learn

Create an HTML file with a paragraph inside a <main> element

Add a CSS rule to set the line height of the paragraph to 1.6

Use semantic HTML5 elements

Ensure the CSS is linked or embedded properly

💡 Why This Matters

🌍 Real World

Web designers and developers often adjust line height to make text easier to read on websites, improving user experience.

💼 Career

Understanding and applying line height is a fundamental skill for front-end developers and UI designers to create accessible and visually pleasing web pages.

1

Create the HTML structure with a paragraph

Write the HTML code to create a <main> element containing a <p> paragraph with the exact text: "Learning to adjust line height improves text readability."

CSS

Hint

Use the <main> tag to wrap your paragraph and write the exact text inside a <p> tag.

2

Add a CSS selector for the paragraph

Add a CSS rule that selects the p element. You only need to write the selector line: p {

CSS

  Learning to adjust line height improves text readability.


p {
  /* Your CSS properties here */
}

Hint

Start your CSS rule by writing p { to target the paragraph.

3

Set the line height property

Inside the p CSS rule, add the property line-height and set it to 1.6. Write exactly: line-height: 1.6;

CSS

p {
  /* Set line height here */
}

Hint

Use the CSS property line-height with the value 1.6 followed by a semicolon.

4

Complete the CSS rule with closing brace

Add the closing brace } to finish the p CSS rule.

CSS

p {
  line-height: 1.6;
  /* Close the CSS rule here */
}

Hint

Close your CSS rule with a } to complete the style block.

Practice

1. What does the CSS property line-height control in a webpage?

easy

A. The vertical space between lines of text

B. The color of the text

C. The font size of the text

D. The horizontal space between words

Solution

1. Step 1: Understand the property purpose

   The line-height property sets the amount of vertical space between lines of text in a block.

2. Step 2: Compare options to definition

   Only The vertical space between lines of text correctly describes vertical spacing between lines, others describe unrelated text styles.

3. Final Answer:

   The vertical space between lines of text -> Option A

4. Quick Check:

   Line height = vertical spacing [OK]

Hint: Line height = space vertically between text lines [OK]

Common Mistakes:

• Confusing line height with font size
• Thinking it controls text color
• Mixing it up with letter spacing

2. Which of the following is the correct syntax to set line height to 1.5 in CSS?

easy

A. lineheight = 1.5;

B. line-height: 1.5;

C. line-height = 1.5px;

D. lineHeight: 1.5;

Solution

1. Step 1: Recall CSS property syntax

   CSS properties use hyphenated names and colon to assign values, ending with semicolon.

2. Step 2: Check each option

   line-height: 1.5; uses correct CSS syntax: line-height: 1.5;. Options B and C use incorrect assignment or units, D uses camelCase which is invalid in CSS.

3. Final Answer:

   line-height: 1.5; -> Option B

4. Quick Check:

   CSS property syntax = property: value; [OK]

Hint: CSS uses hyphen and colon, no equals sign [OK]

Common Mistakes:

• Using equals sign instead of colon
• Adding units like px to unitless line height
• Using camelCase instead of hyphen

3. Given this CSS:

p { font-size: 16px; line-height: 2; }

What is the computed line height in pixels for the paragraph text?

medium

A. 16px

B. 2px

C. 32px

D. 8px

Solution

1. Step 1: Understand line-height as a multiplier

   When line-height is a number (like 2), it multiplies the font size to get the line height in pixels.

2. Step 2: Calculate line height

   Font size is 16px, line-height is 2, so 16px x 2 = 32px.

3. Final Answer:

   32px -> Option C

4. Quick Check:

   Line height = font size x number [OK]

Hint: Multiply font size by line-height number [OK]

Common Mistakes:

• Confusing line-height number as pixels directly
• Using line-height value as font size
• Ignoring multiplication and picking wrong units

4. This CSS code is intended to increase line spacing but does not work as expected:

p { line-height: 20; }

What is the error?

medium

A. Missing units like 'px' for line-height value

B. line-height cannot be set on paragraphs

C. line-height value must be less than 1

D. line-height property name is misspelled

Solution

1. Step 1: Check line-height value type

   The value 20 without units is treated as a multiplier, but 20 is unusually large and likely intended as pixels.

2. Step 2: Identify missing units

   To specify exact pixel spacing, units like 'px' are required: line-height: 20px;. Without units, 20 means 20 times font size, which is huge and may cause unexpected layout.

3. Final Answer:

   Missing units like 'px' for line-height value -> Option A

4. Quick Check:

   Units needed for absolute line height values [OK]

Hint: Add units like px for fixed line height values [OK]

Common Mistakes:

• Using large numbers without units expecting pixels
• Thinking line-height can't be set on paragraphs
• Misspelling property name

5. You want to create a responsive paragraph where line height adjusts nicely with font size for readability. Which CSS rule achieves this best?

hard

A. p { font-size: 16px; line-height: 1.5rem; }

B. p { font-size: 16px; line-height: 24px; }

C. p { font-size: 1.2rem; line-height: 24px; }

D. p { font-size: 1.2rem; line-height: 1.5; }

Solution

1. Step 1: Understand responsive units

   Using rem units for font size scales text with root font size, good for responsiveness.

2. Step 2: Use unitless line-height for flexibility

   Setting line-height: 1.5; as a number scales line height relative to font size, adapting well on different devices.

3. Step 3: Compare options

   p { font-size: 1.2rem; line-height: 1.5; } uses rem for font size and unitless line-height, making it flexible. Options B and C fix line height in pixels, less flexible. p { font-size: 16px; line-height: 1.5rem; } mixes units incorrectly.

4. Final Answer:

   p { font-size: 1.2rem; line-height: 1.5; } -> Option D

5. Quick Check:

   Unitless line-height + rem font size = responsive text [OK]

Hint: Use unitless line-height with rem font size for responsiveness [OK]

Common Mistakes:

• Using fixed pixel line height with scalable font size
• Mixing units in line-height property
• Not using unitless line-height for flexible spacing