CSS for styling web pages in Intro to Computing - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does CSS stand for?

CSS stands for Cascading Style Sheets. It is used to style and layout web pages.

beginner

How does CSS separate content from design?

CSS keeps the HTML content clean by handling all the visual styles separately, like colors, fonts, and layout, so the content and design are managed independently.

beginner

What is the role of selectors in CSS?

Selectors tell the browser which HTML elements to style. For example, p selects all paragraphs, and .className selects elements with a specific class.

intermediate

Explain the box model in CSS.

The CSS box model describes how elements are wrapped in boxes made of content, padding, border, and margin. It helps control spacing and layout.

beginner

What is the difference between classes and IDs in CSS?

Classes can be used on multiple elements to apply the same styles, while IDs are unique and used for a single element. Classes start with a dot (.) and IDs with a hash (#).

Which CSS property changes the background color of an element?

A border-style

B background-color

C font-size

D color

The background-color property sets the background color of an element.

What does the CSS selector .menu select?

A All elements with id 'menu'

B All <menu> HTML elements

C All elements with class 'menu'

D All elements named 'menu'

A dot (.) before a name selects all elements with that class.

Which part of the CSS box model controls the space outside the border?

A Margin

B Padding

C Content

D Border

Margin is the space outside the border, separating elements from others.

How do you apply CSS styles directly inside an HTML element?

A Using the style attribute

B Using an external stylesheet

C Using the <style> tag

D Using a script tag

The style attribute inside an HTML tag applies CSS directly to that element.

Which CSS property controls the font size of text?

A font-weight

B font-style

C text-decoration

D font-size

The font-size property sets how big or small the text appears.

Describe the CSS box model and explain how it affects the layout of a web page.

Think of an element as a box with layers around it.

Explain how CSS selectors work and give examples of different types of selectors.

Selectors tell CSS which parts of the page to style.

Practice

1. What is the main purpose of CSS in web pages?

easy

A. To style and change the appearance of web page elements

B. To write the content of the web page

C. To create the structure of the web page

D. To store data on the server

Solution

1. Step 1: Understand CSS role

   CSS is used to style web pages by changing colors, fonts, and layout.

2. Step 2: Differentiate from other web technologies

   HTML writes content, JavaScript adds behavior, CSS styles appearance.

3. Final Answer:

   To style and change the appearance of web page elements -> Option A

4. Quick Check:

   CSS = Styling [OK]

Hint: Remember: CSS = Style, HTML = Content [OK]

Common Mistakes:

• Confusing CSS with HTML content writing
• Thinking CSS stores data
• Mixing CSS with JavaScript functionality

2. Which of the following is the correct CSS syntax to change the text color to blue?

easy

A. color: blue;

B. color = blue;

C. text-color: blue;

D. font-color = blue;

Solution

1. Step 1: Recall CSS property syntax

   CSS uses property: value; format, for example, color: blue;

2. Step 2: Check each option

   color: blue; uses correct syntax with colon and semicolon; others use wrong symbols or property names.

3. Final Answer:

   color: blue; -> Option A

4. Quick Check:

   Property: value; = color: blue; [OK]

Hint: CSS uses colon and semicolon for properties [OK]

Common Mistakes:

• Using equal sign instead of colon
• Using incorrect property names like text-color
• Omitting semicolon at end

3. What will be the background color of the paragraph after applying this CSS?

p { background-color: yellow; }

medium

A. The paragraph text color will be yellow

B. The paragraph background will be yellow

C. The paragraph background will be transparent

D. The paragraph font size will change

Solution

1. Step 1: Identify the selector and property

   The selector 'p' targets all paragraphs; property 'background-color' sets background color.

2. Step 2: Understand the effect of background-color

   Setting background-color to yellow colors the paragraph's background yellow, not text or font size.

3. Final Answer:

   The paragraph background will be yellow -> Option B

4. Quick Check:

   background-color: yellow = yellow background [OK]

Hint: background-color changes background, not text color [OK]

Common Mistakes:

• Confusing background-color with text color
• Thinking font size changes with background-color
• Ignoring the selector effect

4. Identify the error in this CSS code snippet:

h1 { font-size 20px; color: red }

medium

A. Color value should be in quotes

B. Wrong selector used

C. Missing colon after font-size property

D. Semicolon missing after color property

Solution

1. Step 1: Check property syntax

   CSS properties require a colon between property and value, e.g., font-size: 20px;

2. Step 2: Identify missing colon

   In the snippet, font-size 20px lacks colon, causing syntax error; color property is correct but missing semicolon is allowed if last.

3. Final Answer:

   Missing colon after font-size property -> Option C

4. Quick Check:

   Property: value; needs colon [OK]

Hint: Every CSS property needs a colon between name and value [OK]

Common Mistakes:

• Omitting colon after property name
• Thinking quotes are needed for color names
• Confusing semicolon necessity at end

5. You want to style all <li> items inside a <ul> with a green font and 18px size, but only if they have the class highlight. Which CSS selector and properties will achieve this?

hard

A. li.highlight ul { color: green; font-size: 18px; }

B. ul.highlight li { color: green; font-size: 18px; }

C. li ul.highlight { color: green; font-size: 18px; }

D. ul li.highlight { color: green; font-size: 18px; }

Solution

1. Step 1: Understand selector structure

   We want li elements with class highlight inside ul. The selector should be ul li.highlight.

2. Step 2: Check properties for styling

   Properties color: green; and font-size: 18px; correctly style font color and size.

3. Final Answer:

   ul li.highlight { color: green; font-size: 18px; } -> Option D

4. Quick Check:

   Selector targets li.highlight inside ul [OK]

Hint: Class selectors use dot after element name: li.highlight [OK]

Common Mistakes:

• Placing class on wrong element in selector
• Reversing element order in selector
• Using incorrect selector syntax