Border radius (rounded corners) in Tailwind - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the Tailwind CSS class rounded do?

It adds a small border radius to an element, making its corners slightly rounded.

beginner

How do you make an element have fully rounded corners (a circle) in Tailwind CSS?

Use the class rounded-full. This sets the border radius to 9999px, making the element perfectly round if its width and height are equal.

beginner

What is the difference between rounded-sm and rounded-lg in Tailwind CSS?

rounded-sm applies a small border radius, while rounded-lg applies a larger border radius, making corners more rounded.

intermediate

How can you round only the top-left corner of an element in Tailwind CSS?

Use the class rounded-tl to apply border radius only to the top-left corner.

intermediate

Why is using Tailwind's border radius classes better than writing custom CSS for rounded corners?

Tailwind classes are consistent, easy to use, and help keep your code clean and maintainable. They also support responsive design and theming.

Which Tailwind class makes an element's corners fully rounded?

A rounded-none

B rounded-full

C rounded-lg

D rounded-sm

rounded-full sets the border radius very high to make corners fully round, like a circle.

What does the class rounded-t do in Tailwind CSS?

A Rounds top-left and top-right corners

B Rounds all corners

C Rounds bottom corners

D Removes border radius

rounded-t rounds only the top-left and top-right corners.

If you want slightly rounded corners, which class should you use?

A rounded-none

B rounded-xl

C rounded-full

D rounded-sm

rounded-sm applies a small border radius for subtle rounding.

How do you remove all rounded corners from an element in Tailwind CSS?

A rounded-remove

B rounded-0

C rounded-none

D rounded-clear

rounded-none removes any border radius, making corners sharp.

Which class rounds only the bottom-right corner of an element?

A rounded-br

B rounded-bl

C rounded-tr

D rounded-tl

rounded-br applies border radius only to the bottom-right corner.

Explain how to use Tailwind CSS classes to round only specific corners of an element.

Think about the corner abbreviations: tl = top-left, br = bottom-right.

Describe the visual difference between using rounded-sm and rounded-full in Tailwind CSS.

Imagine a square with slightly rounded edges versus a circle.

Practice

1. What does the Tailwind CSS class rounded do to an element?

easy

A. Adds rounded corners to all sides of the element

B. Adds a border to the element

C. Changes the background color of the element

D. Adds padding inside the element

Solution

1. Step 1: Understand the purpose of rounded class

   The rounded class in Tailwind CSS is used to add rounded corners to elements.

2. Step 2: Identify what rounded affects

   It affects the border radius, making the corners curved instead of sharp.

3. Final Answer:

   Adds rounded corners to all sides of the element -> Option A

4. Quick Check:

   Rounded corners = rounded class [OK]

Hint: Rounded corners come from the rounded class [OK]

Common Mistakes:

• Confusing rounded corners with borders
• Thinking it changes colors
• Assuming it adds padding

2. Which Tailwind class correctly applies a medium border radius to an element?

easy

A. rounded-lg

B. rounded-md

C. rounded-xl

D. rounded-sm

Solution

1. Step 1: Recall Tailwind border radius sizes

   Tailwind uses rounded-sm for small, rounded-md for medium, rounded-lg for large, and rounded-xl for extra large radius.

2. Step 2: Identify the medium size class

   The medium border radius class is rounded-md.

3. Final Answer:

   rounded-md -> Option B

4. Quick Check:

   Medium radius = rounded-md [OK]

Hint: Medium radius uses rounded-md class [OK]

Common Mistakes:

• Choosing rounded-lg or rounded-xl for medium
• Confusing rounded-sm as medium
• Misspelling class names

3. What will be the visual effect of this HTML snippet?

<div class="w-32 h-32 bg-blue-500 rounded-tl-lg rounded-br-lg"></div>

medium

A. No corners are rounded

B. All corners are large rounded

C. Only the top-left corner is rounded

D. The top-left and bottom-right corners are large rounded; others are sharp

Solution

1. Step 1: Understand the classes used

   The classes rounded-tl-lg and rounded-br-lg apply large rounding to the top-left and bottom-right corners respectively.

2. Step 2: Visualize the effect on the box

   Only these two corners will be rounded large; the other corners remain sharp (no rounding).

3. Final Answer:

   The top-left and bottom-right corners are large rounded; others are sharp -> Option D

4. Quick Check:

   Specific corners rounded = rounded-tl-lg and rounded-br-lg [OK]

Hint: Classes with corner abbreviations round only those corners [OK]

Common Mistakes:

• Assuming all corners round with these classes
• Mixing corner abbreviations
• Ignoring the size suffix like -lg

4. Identify the error in this Tailwind usage:

<button class="rounded-top-md bg-green-400 p-4">Click</button>

medium

A. The class rounded-top-md is invalid in Tailwind

B. The padding class p-4 is incorrect

C. The background color class bg-green-400 is invalid

D. The button tag cannot have rounded corners

Solution

1. Step 1: Check the border radius class syntax

   Tailwind uses rounded-t for top corners, not rounded-top.

2. Step 2: Confirm other classes

   p-4 and bg-green-400 are valid Tailwind classes, and buttons can have rounded corners.

3. Final Answer:

   The class rounded-top-md is invalid in Tailwind -> Option A

4. Quick Check:

   Correct top rounding class = rounded-t-md [OK]

Hint: Use rounded-t-md for top corners, not rounded-top-md [OK]

Common Mistakes:

• Using non-existent class names
• Confusing padding with border radius
• Thinking buttons can't have rounded corners

5. You want a card with only the bottom corners rounded to extra large size using Tailwind. Which single class achieves this?

hard

A. rounded-xl

B. rounded-bl-xl rounded-br-xl

C. rounded-b-xl

D. rounded-bottom-xl

Solution

1. Step 1: Understand bottom corner rounding classes

   rounded-b-xl rounds both bottom-left and bottom-right corners to extra large size.

2. Step 2: Compare with other options

   rounded-bl-xl and rounded-br-xl individually round corners but rounded-b-xl is simpler and correct. rounded-xl rounds all corners, and rounded-bottom-xl is invalid.

3. Final Answer:

   rounded-b-xl -> Option C

4. Quick Check:

   Bottom corners extra large = rounded-b-xl [OK]

Hint: Use rounded-b-xl for both bottom corners [OK]

Common Mistakes:

• Using invalid class rounded-bottom-xl
• Using separate classes when shorthand exists
• Choosing rounded-xl which rounds all corners