Container query preparation in SASS - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a container query in CSS?

A container query lets you apply styles to an element based on the size of its container, not the whole viewport. It helps make components adapt to their space.

beginner

How do you declare a container in CSS for container queries?

Use container-type property on the parent element. For example, container-type: inline-size; makes the container track its inline size (width in horizontal writing modes).

intermediate

Why prepare your Sass code for container queries?

Preparing Sass helps organize styles, reuse code, and easily add container queries later without rewriting everything.

intermediate

What Sass feature helps you write container queries cleanly?

Sass mixins let you write container query blocks once and reuse them with different parameters for cleaner code.

beginner

How do container queries improve responsive design compared to media queries?

Container queries respond to the container's size, so components adapt wherever they are used, not just based on the whole screen size like media queries.

Which CSS property defines a container for container queries?

A query-container

B container-query

C container-type

D container-style

The correct property to declare a container is container-type.

What does container-type: inline-size; do?

A Tracks the container's width for queries

B Tracks the container's height for queries

C Disables container queries

D Sets container background color

inline-size tracks the container's inline size (width in horizontal writing modes), enabling queries based on width.

Why use Sass mixins for container queries?

A To create animations

B To disable container queries

C To write JavaScript inside CSS

D To reuse container query styles easily

Mixins help reuse container query styles without repeating code.

Container queries respond to which size?

A Container size

B Viewport size

C Font size

D Screen resolution

Container queries respond to the size of the container element.

Which is NOT a benefit of container queries?

A Components adapt to container size

B Styles depend on viewport only

C Better modular design

D More flexible responsive layouts

Container queries do NOT depend only on viewport size; that is media queries.

Explain how to prepare Sass code for container queries in a project.

Think about how Sass features help manage container queries.

Describe the difference between container queries and media queries.

Focus on what triggers the style changes.

Practice

1. What is the main purpose of using @container in Sass?

easy

A. To reset all container styles

B. To create animations for containers

C. To define variables inside containers

D. To apply styles based on the size of an element's container

Solution

1. Step 1: Understand container queries

   Container queries allow styling elements depending on their container's size, not the viewport.

2. Step 2: Role of @container in Sass

   The @container rule in Sass is used to write container queries clearly and apply styles conditionally based on container size.

3. Final Answer:

   To apply styles based on the size of an element's container -> Option D

4. Quick Check:

   Container queries = style by container size [OK]

Hint: Remember: @container styles depend on container size, not viewport [OK]

Common Mistakes:

• Confusing container queries with media queries
• Thinking @container creates animations
• Using @container to define variables

2. Which CSS property must be set on a container element to enable container queries in Sass?

easy

A. container-type

B. container-size

C. container-query

D. container-style

Solution

1. Step 1: Identify container query activation property

   To use container queries, the container must declare container-type to enable size-based queries.

2. Step 2: Verify other options

   container-size, container-query, and container-style are not valid CSS properties for this purpose.

3. Final Answer:

   container-type -> Option A

4. Quick Check:

   Enable container queries = container-type [OK]

Hint: Set container-type to activate container queries on an element [OK]

Common Mistakes:

• Using non-existent properties like container-query
• Confusing container-type with container-size
• Forgetting to set container-type on the container

3. Given the Sass code below, what background color will the .box have if its container width is 500px?

@container (min-width: 600px) {
  .box {
    background-color: blue;
  }
}
.box {
  background-color: red;
}

medium

A. Blue

B. Red

C. No background color

D. Green

Solution

1. Step 1: Understand the container query condition

   The container query applies styles only if the container's width is at least 600px.

2. Step 2: Check container width against condition

   The container width is 500px, which is less than 600px, so the container query block does not apply.

3. Step 3: Determine fallback style

   The .box outside the container query has background-color: red;, so this style applies.

4. Final Answer:

   Red -> Option B

5. Quick Check:

   Container width 500px < 600px = red background [OK]

Hint: Check container width against min-width condition to pick color [OK]

Common Mistakes:

• Assuming container query applies regardless of container size
• Confusing container width with viewport width
• Ignoring fallback styles outside @container

4. Identify the error in the following Sass container query code:

@container (max-width 400px) {
  .card {
    padding: 1rem;
  }
}

medium

A. Container queries cannot use max-width

B. Incorrect selector inside @container

C. Missing colon after max-width

D. Padding value should be in px, not rem

Solution

1. Step 1: Check container query syntax

   The condition inside @container must have a colon after the property name, e.g., max-width: 400px.

2. Step 2: Verify other options

   The selector .card is valid, padding in rem is allowed, and max-width is a valid container query condition.

3. Final Answer:

   Missing colon after max-width -> Option C

4. Quick Check:

   Container query conditions need colons [OK]

Hint: Always use colon after property in container query conditions [OK]

Common Mistakes:

• Omitting colon in container query conditions
• Thinking max-width is invalid in container queries
• Confusing units for padding

5. You want to style a .card component differently when its container is narrower than 300px or wider than 700px using Sass container queries. Which of the following is the correct way to write this?

hard

A. @container (max-width: 300px), (min-width: 700px) { .card { font-size: 1.2rem; } }

B. @container (max-width: 300px) and (min-width: 700px) { .card { font-size: 1.2rem; } }

C. @container (max-width 300px), (min-width 700px) { .card { font-size: 1.2rem; } }

D. @container (width < 300px), (width > 700px) { .card { font-size: 1.2rem; } }

Solution

1. Step 1: Understand container query syntax for multiple conditions

   Multiple conditions separated by commas mean OR logic. Use colons after properties.

2. Step 2: Analyze each option

   @container (max-width: 300px), (min-width: 700px) { .card { font-size: 1.2rem; } } correctly uses commas and colons. @container (max-width: 300px) and (min-width: 700px) { .card { font-size: 1.2rem; } } uses AND which requires both conditions simultaneously (impossible here). @container (max-width 300px), (min-width 700px) { .card { font-size: 1.2rem; } } misses colons. @container (width < 300px), (width > 700px) { .card { font-size: 1.2rem; } } uses invalid syntax with < and >.

3. Final Answer:

   @container (max-width: 300px), (min-width: 700px) { .card { font-size: 1.2rem; } } -> Option A

4. Quick Check:

   Use commas for OR, colons after properties [OK]

Hint: Use commas for OR conditions and colons after properties [OK]

Common Mistakes:

• Using 'and' instead of commas for OR conditions
• Omitting colons in conditions
• Using invalid operators like < or > in container queries