HSL colors in CSS - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to set the background color using HSL with hue 120.

CSS

background-color: hsl([1], 100%, 50%);

Drag options to blanks, or click blank then click option'

A120

B240

C0

D60

Attempts:

3 left

💡 Hint

Common Mistakes

Using a hue value outside 0-360 range.

Confusing hue with saturation or lightness.

The hue value 120 represents green in HSL color. This sets the background color to bright green.

2fill in blank

medium

Complete the code to set the text color to a semi-transparent red using HSL with 50% lightness.

CSS

color: hsla(0, 100%, [1]%, 0.5);

Drag options to blanks, or click blank then click option'

A50

B25

C75

D100

Attempts:

3 left

💡 Hint

Common Mistakes

Using 100% lightness which results in white.

Confusing saturation with lightness.

Lightness at 50% gives a balanced red color. The alpha 0.5 makes it semi-transparent.

3fill in blank

hard

Fix the error in the HSL color code to make the background blue.

CSS

background-color: hsl([1], 100%, 50%);

Drag options to blanks, or click blank then click option'

A360

B60

C240

D120

Attempts:

3 left

💡 Hint

Common Mistakes

Using 360 which is red, not blue.

Mixing up hue values.

Hue 240 corresponds to blue on the color wheel, so this sets the background to blue.

4fill in blank

hard

Fill both blanks to create a pastel purple background with 70% lightness and 50% saturation.

CSS

background-color: hsl([1], [2]%, 70%);

Drag options to blanks, or click blank then click option'

A270

B50

C100

D30

Attempts:

3 left

💡 Hint

Common Mistakes

Using 100% saturation which makes the color very bright.

Confusing hue values for purple.

Hue 270 is purple. Saturation 50% with lightness 70% creates a soft pastel purple color.

5fill in blank

hard

Fill all three blanks to create a dark olive green color with hue 120, 40% saturation, and 25% lightness.

CSS

background-color: hsl([1], [2]%, [3]%);

Drag options to blanks, or click blank then click option'

A120

B40

C25

D60

Attempts:

3 left

💡 Hint

Common Mistakes

Using 60% lightness which is too bright for dark olive.

Mixing up saturation and lightness percentages.

Hue 120 is green, 40% saturation makes it less bright, and 25% lightness makes it dark, resulting in dark olive green.

Practice

1. What does the hsl(120, 100%, 50%) color represent in CSS?

easy

A. A bright green color

B. A dark blue color

C. A light red color

D. A gray color

Solution

1. Step 1: Understand the HSL parameters

   The first value (120) is the hue, which represents green on the color wheel.

2. Step 2: Interpret saturation and lightness

   Saturation is 100%, meaning full color intensity, and lightness is 50%, meaning normal brightness.

3. Final Answer:

   A bright green color -> Option A

4. Quick Check:

   Hue 120° = green, full saturation and medium lightness = bright green [OK]

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

Common Mistakes:

• Confusing hue degrees with RGB values
• Mixing up saturation and lightness effects
• Assuming 100% lightness means white

2. Which of the following is the correct syntax to set a background color using HSL in CSS?

easy

A. background-color: hsl(240, 100%, 50%);

B. background-color: hsl[240, 100%, 50%];

C. background-color: hsl{240, 100%, 50%};

D. background-color: hsl 240, 100%, 50%;

Solution

1. Step 1: Recall CSS function syntax

   CSS functions use parentheses () with comma-separated values inside.

2. Step 2: Check each option's syntax

   background-color: hsl(240, 100%, 50%); uses parentheses and commas correctly; others use brackets, braces, or missing parentheses.

3. Final Answer:

   background-color: hsl(240, 100%, 50%); -> Option A

4. Quick Check:

   HSL uses parentheses and commas in CSS [OK]

Hint: Use parentheses () with commas for HSL in CSS [OK]

Common Mistakes:

• Using square brackets or curly braces instead of parentheses
• Omitting commas between values
• Writing HSL values without parentheses

3. What color will the following CSS produce?

color: hsl(0, 0%, 50%);

medium

A. Bright red

B. Medium gray

C. Dark blue

D. Light green

Solution

1. Step 1: Analyze hue and saturation values

   Hue is 0°, but saturation is 0%, meaning no color saturation (gray scale).

2. Step 2: Interpret lightness value

   Lightness is 50%, which is medium brightness gray.

3. Final Answer:

   Medium gray -> Option B

4. Quick Check:

   Saturation 0% means gray, lightness 50% = medium gray [OK]

Hint: Saturation 0% always gives gray, lightness controls brightness [OK]

Common Mistakes:

• Ignoring saturation and assuming hue affects color
• Confusing lightness with saturation
• Thinking 0% saturation still shows color

4. Identify the error in this CSS rule:

p { color: hsl(360, 120%, 50%); }

medium

A. Missing semicolon after color property

B. Hue value cannot be 360

C. Lightness cannot be 50%

D. Saturation cannot be more than 100%

Solution

1. Step 1: Check hue value range

   Hue can be 0 to 360 degrees; 360 is valid (same as 0).

2. Step 2: Check saturation and lightness ranges

   Saturation must be between 0% and 100%; 120% is invalid.

3. Final Answer:

   Saturation cannot be more than 100% -> Option D

4. Quick Check:

   Saturation max is 100% in HSL [OK]

Hint: Saturation and lightness must be 0%-100% [OK]

Common Mistakes:

• Thinking hue cannot be 360
• Ignoring invalid saturation values
• Assuming missing semicolon causes error here

5. You want to create a smooth color transition from red to green using HSL. Which CSS snippet correctly animates the hue from 0° to 120° while keeping saturation and lightness constant?

hard

A. @keyframes colorChange { from { color: hsl(0, 50%, 100%); } to { color: hsl(120, 50%, 100%); } }

B. @keyframes colorChange { from { color: hsl(0, 100%, 0%); } to { color: hsl(120, 100%, 0%); } }

C. @keyframes colorChange { from { color: hsl(0, 100%, 50%); } to { color: hsl(120, 100%, 50%); } }

D. @keyframes colorChange { from { color: hsl(0, 0%, 50%); } to { color: hsl(120, 0%, 50%); } }

Solution

1. Step 1: Understand the goal of smooth hue transition

   Hue should animate from 0° (red) to 120° (green) with saturation and lightness fixed.

2. Step 2: Check each option's saturation and lightness

   @keyframes colorChange { from { color: hsl(0, 100%, 50%); } to { color: hsl(120, 100%, 50%); } } keeps saturation 100% and lightness 50%, which produces vivid colors. Others have incorrect saturation or lightness values causing dull or black colors.

3. Final Answer:

   @keyframes colorChange { from { color: hsl(0, 100%, 50%); } to { color: hsl(120, 100%, 50%); } } -> Option C

4. Quick Check:

   Animate hue 0° to 120° with full saturation and medium lightness [OK]

Hint: Keep saturation and lightness constant for smooth hue animation [OK]

Common Mistakes:

• Changing saturation or lightness during hue animation
• Using 0% lightness which results in black
• Using 0% saturation which results in gray