1. What is CSS?
CSS stands for Cascading Style Sheets. It is a stylesheet language used for describing the presentation of a document written in HTML.

2. What are the main components of CSS?
The main components of CSS are:
– Selector: It selects the HTML element(s) to apply the style to.
– Property: It sets the style of the selected element.
– Value: It specifies the value for the property.

3. What is the difference between inline, internal, and external CSS?
– Inline CSS: It is applied directly to an HTML element using the “style” attribute.
– Internal CSS: It is defined within the “style” tag in the head section of an HTML file.
– External CSS: It is defined in a separate CSS file and linked to HTML using the “link” tag.

4. How can we include CSS styles in a web page?
CSS styles can be included in a web page by using inline, internal, or external CSS.

5. What are the advantages of using external CSS?
The advantages of using external CSS are:
– It makes the HTML code clean and easy to maintain.
– Multiple HTML files can share the same CSS file, reducing code duplication.
– It allows for centralizing the styling of a website, making it consistent across all pages.

6. What is a CSS selector?
A CSS selector is used to select the HTML element(s) on which a CSS rule should be applied. Selectors can be based on element types, class names, IDs, attributes, or their relationships with other elements.

7. What is the box model in CSS?
The box model refers to the concept of treating every HTML element as a rectangular box. It consists of properties like margin, border, padding, and content area. These properties determine how elements are displayed and interact with each other.

8. What is the difference between margin and padding?
– Margin: It creates space outside the element’s border. It is transparent and doesn’t have a background color.
– Padding: It creates space within the element’s border. It can have a background color or image.

9. What does the “float” property do in CSS?
The “float” property is used to specify how an element should float (align) within its parent container. It is commonly used to create layouts where elements can be positioned side by side or wrapped around each other.

10. What is the difference between absolute and relative positioning?
– Absolute position: It allows an element to be positioned relative to its nearest positioned ancestor or to the entire page if no positioned ancestor is found.
– Relative position: It positions an element relative to its normal position, thus, affecting the positioning of other elements around it.

11. What is a pseudo-class in CSS?
A pseudo-class is used to define a specific state of an element, such as when it is hovered over or selected. Pseudo-classes are denoted with a colon (:) followed by the name of the class.

12. What is the “box-sizing” property used for?
The “box-sizing” property is used to specify how the total width and height of an element is calculated. It can be set to “content-box” (default), which includes only the content area, or “border-box”, which includes the content, padding, and border areas.

13. What is the CSS “display” property used for?
The “display” property is used to specify how an element should be displayed. It can take values like “block”, “inline”, “inline-block”, and “none”, among others.

14. What is the difference between “em” and “rem” units in CSS?
– “em” unit: It represents a multiple of the font size of its parent element. For example, if the font size of the parent is 16px and the child element is set to 2em, it will be 32px.
– “rem” unit: It represents a multiple of the font size of the root element (usually the element). It allows for easier and more consistent scaling across the entire document.

15. What is a CSS pseudo-element?
A CSS pseudo-element is used to style a specific part of an element, such as the first letter, or the first line of a paragraph. Pseudo-elements are denoted with double colons (::) followed by the name of the pseudo-element.

16. How can we vertically center an element in CSS?
To vertically center an element in CSS, we can use the following combination of properties:
“`
.parent {
display: flex;
align-items: center;
}
“`

17. What is the “z-index” property used for in CSS?
The “z-index” property is used to specify the stack order (layering) of positioned elements. It controls which elements should be displayed in front or behind other elements. Higher z-index values are displayed on top.

18. What is a CSS media query?
A CSS media query is used to apply different styles to a web page based on the characteristics of the device or browser being used. It allows for creating responsive designs that adapt to different screen sizes and conditions.

19. What is the “background” property used for in CSS?
The “background” property is used to set the background color, image, and other properties of an element. It can be used to create patterns, gradients, and add images to the background of an element.

20. What is the CSS “overflow” property used for?
The “overflow” property is used to control what happens when content overflows the boundaries of an element. It can be set to values like “visible” (default), “hidden”, “scroll”, or “auto”.

1. What is the CSS box model?
The CSS box model is a way of representing elements on a webpage as rectangular boxes. It consists of the content area, padding, border, and margin.

2. What is the difference between “display: inline” and “display: inline-block”?
“Display: inline” makes an element behave like an inline element, while “display: inline-block” makes an element behave like an inline element but allows it to have padding and margin.

3. How do you center an element horizontally and vertically?
To center an element horizontally, you can use “margin: 0 auto.” To center an element vertically, you can use “display: flex” and “align-items: center.”

4. What is the difference between “position: relative” and “position: absolute”?
“Position: relative” positions an element relative to its normal position, while “position: absolute” positions an element relative to its nearest positioned ancestor.

5. What is the “z-index” property used for?
The “z-index” property is used to specify the stacking order of elements. Elements with a higher “z-index” value are stacked above elements with a lower value.

6. What are CSS pseudo-classes?
CSS pseudo-classes are used to select elements that are in a specific state or condition, such as “hover,” “active,” or “first-child.”

7. What is the difference between “opacity” and “rgba()”?
“Opacity” is a property that controls the transparency of an element, while “rgba()” is a function that allows you to specify the color of an element using red, green, blue, and alpha (transparency) values.

8. How can you create a responsive layout using CSS?
You can create a responsive layout using CSS by using media queries to apply different styles based on the viewport size. Additionally, using percentage-based widths and heights, and flexible units like “em” or “rem” can help achieve responsiveness.

9. What is the difference between “em” and “rem” units?
“Em” units are relative to the font-size of the element, while “rem” units are relative to the font-size of the root element (usually the “html” element).

10. What is a CSS preprocessor?
A CSS preprocessor is a scripting language that extends the functionality of CSS by allowing variables, functions, inheritance, and other programming features to generate CSS stylesheets.

11. How do you create an animation in CSS?
You can create an animation in CSS by using the “@keyframes” rule to define the animation and the “animation” property to apply it to an element. The animation can then be triggered using various CSS pseudo-classes or JavaScript.

12. How can you make text gradient in CSS?
You can make text gradient in CSS by using the “background-clip” property with the “text” value and setting the background to a linear gradient.

13. What is the “flexbox” layout in CSS?
The “flexbox” layout is a CSS layout mode that provides a flexible way to distribute space among elements in a container, even when their sizes are unknown or dynamic.

14. How do you create a sticky/fixed header in CSS?
You can create a sticky/fixed header in CSS by using the “position: fixed” property on the header element and adjusting the top or bottom position as needed.

15. How can you apply different styles to different browsers using CSS?
You can apply different styles to different browsers using CSS by using CSS hacks or browser-specific CSS prefixes (e.g., “-webkit-“, “-moz-“, “-ms-“).

16. What is CSS Grid Layout?
CSS Grid Layout is a two-dimensional layout system that allows you to create grid-based layouts with columns and rows, providing precise control over the placement and sizing of elements.

17. How can you create a responsive navigation menu in CSS?
You can create a responsive navigation menu in CSS by using media queries to change the layout or visibility of the menu based on the viewport size. Additionally, you can use CSS transitions or animations to create responsive menu interactions.

18. What is the difference between pseudo-elements “::before” and “::after”?
The “::before” pseudo-element inserts content before the selected element, while the “::after” pseudo-element inserts content after the selected element. These pseudo-elements are often used to add decorative or additional content to an element.

19. How do you create a tooltip in CSS?
You can create a tooltip in CSS by using the “::before” or “::after” pseudo-elements and setting their content, position, and appearance using CSS properties like “content,” “position,” “background,” and “border.”

20. What is the “currentColor” keyword in CSS?
The “currentColor” keyword is used to represent the value of the current color property. It allows you to use the same color as the parent element without explicitly specifying it.