Arbitrary color values in Tailwind - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are arbitrary color values in Tailwind CSS?

Arbitrary color values let you use any color you want by writing it directly inside square brackets, like <code>bg-[#123abc]</code>. This means you are not limited to Tailwind's default colors.

beginner

How do you write a background color using an arbitrary hex color in Tailwind?

You write the class like this: <code>bg-[#ff6347]</code>. This sets the background color to the hex color #ff6347 (tomato red).

intermediate

Can you use arbitrary color values with opacity in Tailwind CSS? How?

Yes! You can add opacity by using RGBA or HSLA colors inside the brackets, for example: bg-[rgba(255,99,71,0.5)] sets a semi-transparent tomato background.

beginner

Why might you choose arbitrary color values over Tailwind's default palette?

Sometimes you need a very specific color that Tailwind does not include. Arbitrary values let you use any color code you want without changing Tailwind's config.

beginner

What is the correct syntax to use an arbitrary color value for text color in Tailwind?

Use text-[color] with your color inside brackets. For example, text-[#4caf50] sets the text color to a green shade.

How do you apply a custom background color #1a2b3c using Tailwind's arbitrary value syntax?

A bg-[#1a2b3c]

B bg-#1a2b3c

C background-[#1a2b3c]

D bg{#1a2b3c}

The correct syntax uses square brackets around the color: bg-[#1a2b3c].

Which of these is a valid way to set semi-transparent red background using arbitrary values?

A bg-rgba(255,0,0,0.5)

B bg-[rgba(255,0,0,0.5)]

C bg-[#ff000080]

D bg-opacity-50-red

You must put the entire rgba color inside brackets: bg-[rgba(255,0,0,0.5)].

Why use arbitrary color values in Tailwind CSS?

A To use colors outside the default palette

B To write CSS without classes

C To disable Tailwind colors

D To create animations

Arbitrary values let you use any color, not just Tailwind's built-in ones.

Which is the correct class to set text color to #123abc in Tailwind?

A color-#123abc

B text-#123abc

C text-[#123abc]

D text{#123abc}

Use square brackets for arbitrary colors: text-[#123abc].

Can you use named CSS colors like 'rebeccapurple' as arbitrary values in Tailwind?

A Only if configured in Tailwind config

B No, only hex colors allowed

C Only with RGB values

D Yes, like bg-[rebeccapurple]

You can use any valid CSS color inside brackets, including named colors.

Explain how to use arbitrary color values in Tailwind CSS and why they are useful.

Think about how you can write any color code inside Tailwind classes.

Describe how to set a semi-transparent background color using arbitrary values in Tailwind.

Remember opacity can be included in rgba or hsla colors.

Practice

1. What is the purpose of using arbitrary color values in Tailwind CSS?
bg-[#ff5733]

easy

A. To create animations with colors

B. To use any custom color not in Tailwind's default palette

C. To add shadows to elements

D. To change font sizes dynamically

Solution

1. Step 1: Understand Tailwind's default colors

   Tailwind provides a set of default colors but sometimes you need a specific shade not included.

2. Step 2: Use arbitrary color values

   By writing colors inside square brackets like bg-[#ff5733], you can use any valid CSS color.

3. Final Answer:

   To use any custom color not in Tailwind's default palette -> Option B

4. Quick Check:

   Arbitrary colors = custom colors [OK]

Hint: Square brackets let you add any color code directly [OK]

Common Mistakes:

• Thinking arbitrary colors create animations
• Confusing color usage with font size changes
• Using arbitrary colors for shadows instead of colors

2. Which of the following is the correct syntax to set a background color to a semi-transparent red using arbitrary values in Tailwind CSS?

easy

A. bg-[rgba(255,0,0,0.5)]

B. bg-rgba(255,0,0,0.5)

C. bg-[rgb(255,0,0,0.5)]

D. bg-(rgba(255,0,0,0.5))

Solution

1. Step 1: Check the correct use of square brackets

   Arbitrary values must be inside square brackets exactly, so bg-[...] is correct.

2. Step 2: Validate the color function syntax

   The color function rgba(255,0,0,0.5) is valid CSS and correctly placed inside brackets.

3. Final Answer:

   bg-[rgba(255,0,0,0.5)] -> Option A

4. Quick Check:

   Correct brackets + valid rgba = bg-[rgba(255,0,0,0.5)] [OK]

Hint: Always wrap color values in square brackets for arbitrary colors [OK]

Common Mistakes:

• Omitting square brackets
• Using parentheses instead of brackets
• Using rgb instead of rgba for transparency

3. What color will the text be if you use this Tailwind class?
text-[hsl(120,100%,50%)]

medium

A. Bright green

B. Bright red

C. Bright blue

D. Bright yellow

Solution

1. Step 1: Understand HSL color values

   HSL stands for hue, saturation, and lightness. Hue 120° corresponds to green.

2. Step 2: Analyze saturation and lightness

   100% saturation and 50% lightness means the color is bright and fully saturated green.

3. Final Answer:

   Bright green -> Option A

4. Quick Check:

   Hue 120° = green [OK]

Hint: Hue 120° in HSL means green color [OK]

Common Mistakes:

• Confusing hue degrees with other colors
• Ignoring saturation and lightness effects
• Assuming default Tailwind colors instead of arbitrary

4. Identify the error in this Tailwind class:
bg-[#12345G]

medium

A. Missing square brackets

B. Wrong prefix, should be 'background-'

C. Invalid hex color code due to 'G'

D. Hex code too short

Solution

1. Step 1: Check hex color validity

   Hex colors only allow digits 0-9 and letters A-F (case-insensitive). 'G' is invalid.

2. Step 2: Confirm brackets and prefix

   Square brackets and prefix bg- are correct here.

3. Final Answer:

   Invalid hex color code due to 'G' -> Option C

4. Quick Check:

   Hex digits must be 0-9 or A-F [OK]

Hint: Hex colors only use 0-9 and A-F letters [OK]

Common Mistakes:

• Ignoring invalid hex characters
• Thinking brackets are missing
• Confusing prefix names

5. You want a button with a background color that changes based on light or dark mode using arbitrary colors. Which Tailwind class combination is correct?

hard

A. bg-[rgb(255,255,255)] dark:bg-[rgb(300,300,300)]

B. bg-[rgb(255,255,255)] bg-dark:[rgb(30,30,30)]

C. bg-[rgb(255,255,255)] dark:bg(rgb(30,30,30))

D. bg-[rgb(255,255,255)] dark:bg-[rgb(30,30,30)]

Solution

1. Step 1: Use correct dark mode prefix

   Tailwind uses dark: prefix to apply styles in dark mode.

2. Step 2: Use correct arbitrary color syntax

   Colors must be inside square brackets with valid CSS color values.

3. Step 3: Validate color values

   RGB values must be between 0 and 255; bg-[rgb(255,255,255)] dark:bg-[rgb(300,300,300)] has invalid 300 values.

4. Final Answer:

   bg-[rgb(255,255,255)] dark:bg-[rgb(30,30,30)] -> Option D

5. Quick Check:

   Correct dark: prefix + valid colors = bg-[rgb(255,255,255)] dark:bg-[rgb(30,30,30)] [OK]

Hint: Use dark: prefix and brackets for dark mode colors [OK]

Common Mistakes:

• Using wrong dark mode prefix syntax
• Omitting square brackets for arbitrary colors
• Using invalid RGB values above 255