State class generation (hover, active, disabled) in SASS - Practice Problems & Coding Challenges

Challenge - 5 Problems

📝 Syntax

intermediate

What is the output CSS of this SASS snippet?

Given this SASS code, what CSS does it generate?

.btn {
  background: blue;
  &:hover {
    background: green;
  }
  &.disabled {
    background: gray;
  }
}

SASS

.btn {
  background: blue;
  &:hover {
    background: green;
  }
  &.disabled {
    background: gray;
  }
}

A

.btn { background: blue; }
.btn:hover { background: gray; }
.btn.disabled { background: green; }

B

.btn { background: blue; }
.btn:hover { background: green; }
.btn.disabled { background: gray; }

C

.btn { background: blue; }
.btn.disabled:hover { background: green; }

D

.btn { background: blue; }
.btn:hover.disabled { background: gray; }

💡 Hint

Look at how the & symbol combines with pseudo-classes and classes.

The & symbol in SASS appends the nested selectors to the parent. &:hover becomes .btn:hover and &.disabled becomes .btn.disabled.

🧠 Conceptual

intermediate

Which selector targets the active state in SASS?

You want to style a button when it is being clicked (active state). Which SASS nested selector correctly targets this state?

SASS

.btn {
  // your code here
}

A &:active { background: red; }

B &.active { background: red; }

C &.disabled { background: red; }

D &:hover { background: red; }

💡 Hint

Active state is a pseudo-class triggered when clicking.

The :active pseudo-class applies styles when the element is being clicked. &.active targets a class named 'active', which is different.

❓ selector

advanced

What CSS does this SASS produce for combined states?

Consider this SASS code:

.btn {
  color: black;
  &:hover, &:focus {
    color: blue;
  }
  &.disabled {
    color: gray;
    pointer-events: none;
  }
}

What is the correct CSS output?

SASS

.btn {
  color: black;
  &:hover, &:focus {
    color: blue;
  }
  &.disabled {
    color: gray;
    pointer-events: none;
  }
}

A

.btn { color: black; }
.btn:hover:focus { color: blue; }
.btn.disabled { color: gray; pointer-events: none; }

B

.btn { color: black; }
.btn:hover, .disabled:focus { color: blue; }
.btn.disabled { color: gray; pointer-events: none; }

C

.btn { color: black; }
.btn:hover, :focus { color: blue; }
.btn.disabled { color: gray; pointer-events: none; }

D

.btn { color: black; }
.btn:hover, .btn:focus { color: blue; }
.btn.disabled { color: gray; pointer-events: none; }

💡 Hint

Check how multiple selectors separated by commas are expanded with &.

The & symbol applies to each selector before the comma separately, so &:hover, &:focus becomes .btn:hover, .btn:focus.

❓ layout

advanced

How to disable pointer events for a disabled button in SASS?

You want to make a button unclickable and visually disabled using SASS. Which nested rule correctly disables pointer events and changes opacity?

SASS

.btn {
  background: green;
  color: white;
  &.disabled {
    // your code here
  }
}

A

opacity: 1;
pointer-events: auto;

B

opacity: 0.5;
pointer-events: auto;

C

opacity: 0.5;
pointer-events: none;

D

opacity: 1;
pointer-events: none;

💡 Hint

Disabled means less visible and no mouse interaction.

Setting opacity to 0.5 dims the button visually, and pointer-events: none disables mouse clicks.

❓ accessibility

expert

Which approach improves accessibility for disabled buttons?

You have a button styled with a .disabled class in SASS. Which additional attribute or practice improves accessibility for keyboard and screen reader users?

SASS

.btn.disabled {
  opacity: 0.5;
  pointer-events: none;
}

A Add aria-disabled="true" attribute and tabindex="-1" to the button element.

B Add role="button" attribute only.

C Add tabindex="0" to make it focusable.

D Remove the button element and replace with a div.

💡 Hint

Disabled elements should not be focusable and should announce their state.

aria-disabled="true" informs assistive tech the button is disabled, and tabindex="-1" removes it from keyboard focus.

Practice

1. What is the main purpose of using state classes like :hover, :active, and .disabled in Sass?

easy

A. To change the appearance of elements based on user interaction or status

B. To add animations to elements automatically

C. To create new HTML elements dynamically

D. To load external CSS files conditionally

Solution

1. Step 1: Understand state classes

   State classes like :hover and :active change how elements look when users interact with them.

2. Step 2: Identify their purpose

   They help show different styles for hover, active, or disabled states to improve user experience.

3. Final Answer:

   To change the appearance of elements based on user interaction or status -> Option A

4. Quick Check:

   State classes change look on interaction [OK]

Hint: State classes show style changes on user actions [OK]

Common Mistakes:

• Thinking state classes create new elements
• Confusing state classes with animations
• Believing state classes load files

2. Which of the following is the correct Sass syntax to create a mixin for hover and active states?

easy

A. @mixin states { :hover { color: blue; } :active { color: red; } }

B. @mixin states { &:hover { color: blue; } &:active { color: red; } }

C. @mixin states { .hover { color: blue; } .active { color: red; } }

D. @mixin states { hover { color: blue; } active { color: red; } }

Solution

1. Step 1: Review Sass mixin syntax

   Mixins use @mixin name { ... } and nested selectors use &:state for pseudo-classes.

2. Step 2: Check correct pseudo-class usage

   Correct syntax uses &:hover and &:active inside the mixin.

3. Final Answer:

   @mixin states { &:hover { color: blue; } &:active { color: red; } } -> Option B

4. Quick Check:

   Use & with :hover and :active in mixins [OK]

Hint: Use & before pseudo-classes inside mixins [OK]

Common Mistakes:

• Omitting & before pseudo-classes
• Using class selectors instead of pseudo-classes
• Missing @mixin keyword

3. Given this Sass code, what color will the button text be when hovered?

@mixin states {
  &:hover { color: green; }
  &:active { color: orange; }
  &.disabled { color: gray; cursor: not-allowed; }
}

.button {
  color: black;
  @include states;
}

medium

A. Green

B. Black

C. Orange

D. Gray

Solution

1. Step 1: Understand the mixin states

   The mixin sets color: green on :hover, color: orange on :active, and gray with disabled class.

2. Step 2: Check the hover state

   When the button is hovered, the :hover style applies, changing text color to green.

3. Final Answer:

   Green -> Option A

4. Quick Check:

   Hover changes color to green [OK]

Hint: Hover state color overrides base color [OK]

Common Mistakes:

• Confusing active color with hover color
• Ignoring the disabled class
• Assuming base color stays on hover

4. Identify the error in this Sass code that tries to create disabled state styles:

@mixin states {
  &:hover { color: blue; }
  &:active { color: red; }
  &:disabled { color: gray; cursor: not-allowed; }
}

.button {
  @include states;
}

medium

A. Cannot use mixins inside class selectors

B. Missing semicolon after color: red

C. Using &:disabled instead of &.disabled for disabled class

D. Mixin name should be capitalized

Solution

1. Step 1: Check pseudo-class vs class usage

   :disabled is a pseudo-class for form elements, but here disabled is a class, so &.disabled is correct.

2. Step 2: Verify other syntax

   Semicolons are present, mixin naming is flexible, and mixins can be used inside classes.

3. Final Answer:

   Using &:disabled instead of &.disabled for disabled class -> Option C

4. Quick Check:

   Use .disabled class selector, not :disabled pseudo-class [OK]

Hint: Use .disabled class, not :disabled pseudo-class [OK]

Common Mistakes:

• Confusing :disabled pseudo-class with .disabled class
• Forgetting semicolons
• Thinking mixins need capital letters

5. You want to create a reusable Sass mixin that adds hover, active, and disabled states to any button. The disabled state should make the button look faded and prevent clicks. Which of these mixins correctly implements this behavior?

hard

A. @mixin button-states {
&:hover { background-color: lightblue; }
&:active { background-color: blue; }
&.disabled { opacity: 1; pointer-events: auto; cursor: not-allowed; }
}

B. @mixin button-states {
&:hover { background-color: lightblue; }
&:active { background-color: blue; }
&:disabled { opacity: 0.5; pointer-events: none; cursor: not-allowed; }
}

C. @mixin button-states {
&:hover { background-color: lightblue; }
&:active { background-color: blue; }
&.disabled { opacity: 0.5; cursor: default; }
}

D. @mixin button-states {
&:hover { background-color: lightblue; }
&:active { background-color: blue; }
&.disabled { opacity: 0.5; pointer-events: none; cursor: not-allowed; }
}

Solution

1. Step 1: Check disabled state styling

   The disabled state should fade the button with opacity: 0.5 and prevent clicks using pointer-events: none.

2. Step 2: Verify cursor and selector usage

   Using &.disabled is correct for a class. Cursor should be not-allowed to show disabled status.

3. Step 3: Compare options

   @mixin button-states { &:hover { background-color: lightblue; } &:active { background-color: blue; } &.disabled { opacity: 0.5; pointer-events: none; cursor: not-allowed; } } correctly uses &.disabled, sets opacity to 0.5, disables pointer events, and sets cursor properly.

4. Final Answer:

   @mixin button-states { &:hover { background-color: lightblue; } &:active { background-color: blue; } &.disabled { opacity: 0.5; pointer-events: none; cursor: not-allowed; } } -> Option D

5. Quick Check:

   Disabled state fades and disables clicks with pointer-events none [OK]

Hint: Use pointer-events:none and opacity for disabled state [OK]

Common Mistakes:

• Using :disabled pseudo-class instead of .disabled class
• Not disabling pointer events on disabled
• Setting opacity to 1 in disabled state