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Updated: May 31, 2026

Flex Gap

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Conclusion

Flex Gap — free browser-based HTML/CSS/JS practice

■ What this exercise teaches Add 16px of space between Flexbox children.

Why it matters in real projects

gap sets spacing between elements at once. Similar patterns appear daily in code review and production UI work.

Step-by-step workflow

1. Read the guide and understand the goal of "Flex Gap" 2. Review the HTML/CSS/JS editor pane and start from the starter code 3. Open hints if stuck; compare your diff with the sample solution 4. Click Run and inspect preview/console output 5. Auto-check looks for output containing: gap, 16. 6. After success, continue with adjacent exercises in the same category

Core concept explained

gap sets spacing between elements at once.

Technical focus

Key HTML elements in this task: div, span, style.

Hint before you peek at the solution

gap: 16px;

Sample solution walkthrough

The solution uses HTML tags such as div, span, style. Check nesting and closing tags. CSS properties include display, gap. Watch selector spelling and specificity. Explanation: gap sets spacing between elements at once. Hint recap: gap: 16px;

Solution code

📝 Sample code
<div class="f"><span>A</span><span>B</span></div>
<style>.f { display: flex; gap: 16px; }</style>

Common mistakes for this exact task

- Skipping the hint: gap: 16px; - Forgetting display:flex on the flex parent breaks alignment

Troubleshooting

Q: Preview does not change after Run A: Ensure you edited the HTML/CSS/JS pane and clicked Run. Q: Looks correct but check fails A: Auto-check looks for output containing: gap, 16. Look for typos, full-width spaces, or unclosed tags. Q: Console shows errors A: Open DevTools Console and fix bracket/quote mismatches at the reported line. Q: Hard to type on mobile A: Use landscape mode or continue on desktop—the same URL keeps progress in localStorage.

Interview / portfolio tips

- Explain the techniques in "Flex Gap" in your own words within 30 seconds - Practice walking through each line of the sample solution on a whiteboard - Be ready to discuss tags: div, span, style - Discuss CSS properties: display, gap - Prepare one alternative approach and why you chose this one

What to do after you pass

Move to the next exercise in the css-layout track, then continue the learning roadmap at /en/learning/layout/.

Keywords

Free hands-on exercise covering Spacing with gap, css-layout, elementary, div, span, style, display, gap, flex gap—search-friendly guide for Flex Gap.

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■ Exercise task

Add 16px of space between Flexbox children.

Hint if stuck

gap: 16px;

10pt

Spacing with gap

Add 16px of space between Flexbox children.

Click error to highlight line. ✕=error ⚠=warning ›=log.

Roadmap · All guides

Deep dive

"Flex Gap" is a elementary-level HTML/CSS/JS exercise. Add 16px of space between Flexbox children. Run it in-browser with automatic checking.

gap sets spacing between elements at once. Similar patterns appear daily in code review and production UI work.

Pair this with the layout roadmap. Exercise #39 reinforces core css-layout skills.

Step-by-step workflow

  1. Read the guide and understand the goal of "Flex Gap"
  2. Review the HTML/CSS/JS editor pane and start from the starter code
  3. Open hints if stuck; compare your diff with the sample solution
  4. Click Run and inspect preview/console output
  5. Auto-check looks for output containing: gap, 16.
  6. After success, continue with adjacent exercises in the same category

How to read the sample solution

The solution uses HTML tags such as div, span, style. Check nesting and closing tags. CSS properties include display, gap. Watch selector spelling and specificity. Explanation: gap sets spacing between elements at once. Hint recap: gap: 16px;

Real-world & career relevance

Flexbox and Grid are standard for dashboards, card UIs, and responsive nav—core "modern CSS" job requirements.

Common mistakes

  • Skipping the hint: gap: 16px;
  • Forgetting display:flex on the flex parent breaks alignment
  • Forgetting display:flex on flex parent
  • Mixing up justify-content vs align-items
  • Only fixed px, no responsive layout

Troubleshooting

Preview does not change after Run
Ensure you edited the HTML/CSS/JS pane and clicked Run.
Looks correct but check fails
Auto-check looks for output containing: gap, 16. Look for typos, full-width spaces, or unclosed tags.
Console shows errors
Open DevTools Console and fix bracket/quote mismatches at the reported line.
Hard to type on mobile
Use landscape mode or continue on desktop—the same URL keeps progress in localStorage.

Interview & portfolio tips

  • Explain the techniques in "Flex Gap" in your own words within 30 seconds
  • Practice walking through each line of the sample solution on a whiteboard
  • Be ready to discuss tags: div, span, style
  • Discuss CSS properties: display, gap
  • Prepare one alternative approach and why you chose this one

Glossary

Flexbox
One-dimensional row/column layout.
Grid
Two-dimensional row and column layout.
gap
Spacing between flex/grid items.

Keywords covered on this page

Free hands-on exercise covering Spacing with gap, css-layout, elementary, div, span, style, display, gap, flex gap—search-friendly guide for Flex Gap.

Related dev tools

Learning roadmap

Learning roadmap →

Related exercises

Frequently asked questions

Is "Spacing with gap" free?

This exercise is free and runs entirely in your browser. No account or credit card required.

Difficulty and time?

"Spacing with gap" is level "elementary". Read the guide first; beginners can usually finish within 30 minutes. Allow 5–15 minutes per exercise. Use hints, then the solution if stuck.

What after a correct answer?

After a correct answer, use "Next exercise". When you finish a category, continue on the <a href="/en/learning/layout/">learning roadmap</a>.

Works on mobile?

Works on mobile browsers, but typing code is easier on a desktop.

Where are other exercises?

All exercises: <a href="/en/learn/">/en/learn/</a> with category filters.

Key takeaway for "Spacing with gap"?

gap sets spacing between elements at once. Hint: gap: 16px;

Where does CSS Layout fit?

Flexbox and Grid are standard for dashboards, card UIs, and responsive nav—core "modern CSS" job requirements.

Step-by-step for "Flex Gap"?

1. Read the guide and understand the goal of "Flex Gap"<br />2. Review the HTML/CSS/JS editor pane and start from the starter code<br />3. Open hints if stuck; compare your diff with the sample solution<br />4. Click Run and inspect preview/console output<br />5. Auto-check looks for output containing: gap, 16.<br />6. After success, continue with adjacent exercises in the same category

How to read the sample solution?

The solution uses HTML tags such as div, span, style. Check nesting and closing tags.<br /><br />CSS properties include display, gap. Watch selector spelling and specificity.<br /><br />Explanation: gap sets spacing between elements at once.<br /><br />Hint recap: gap: 16px;

Something is not working?

<strong>Preview does not change after Run</strong> → Ensure you edited the HTML/CSS/JS pane and clicked Run.<br /><strong>Looks correct but check fails</strong> → Auto-check looks for output containing: gap, 16. Look for typos, full-width spaces, or unclosed tags.<br /><strong>Console shows errors</strong> → Open DevTools Console and fix bracket/quote mismatches at the reported line.<br /><strong>Hard to type on mobile</strong> → Use landscape mode or continue on desktop—the same URL keeps progress in localStorage.

Career / interview angle?

Explain the techniques in "Flex Gap" in your own words within 30 seconds Practice walking through each line of the sample solution on a whiteboard Be ready to discuss tags: div, span, style Discuss CSS properties: display, gap Prepare one alternative approach and why you chose this one

Related dev tools?

<a href="/en/tools/css-grid/">CSS Grid Generator</a>, <a href="/en/tools/aspect-ratio/">Aspect Ratio</a>

Prerequisites?

Read the <a href="/en/learning/layout/">Learning roadmap</a> chapter first.

Can I change the starter code?

Yes—if it works. Understanding the starter first, then adding minimal diffs, speeds up learning.

What do the points mean?

10pt is a difficulty hint, not a score you must maximize.