1. What is CSS and what are its benefits?

CSS (Cascading Style Sheets) is a style sheet language used for describing the presentation of a document written in HTML or XML. Benefits of using CSS include separation of content and presentation, faster page load times, improved website accessibility, and easier website maintenance.

2. What is the syntax of a CSS rule?

A CSS rule consists of a selector and a declaration block. The selector identifies which HTML element(s) the rule applies to, and the declaration block contains one or more property-value pairs that define the style of the element.

3. What is a CSS selector?

A CSS selector is a pattern used to select one or more HTML elements for styling. Selectors can be based on element type, class, ID, attribute, and other factors.

4. What is the difference between class and ID selectors?

A class selector is used to apply a style to all elements with a particular class, while an ID selector is used to apply a style to a specific element with a unique ID. IDs should be unique on a page, while classes can be used multiple times.

5. What is the box model in CSS?

The box model is a design concept in CSS that represents an HTML element as a rectangular box. It consists of the content area, padding, border, and margin.

6. What is the CSS display property?

The CSS display property determines how an element should be displayed. The most common values are block, inline, and none, but there are many others, including flex, grid, and table.

7. What is the CSS float property?

The CSS float property allows an element to be floated to the left or right of its container. This is commonly used for creating layouts with multiple columns.

8. What is the CSS position property?

The CSS position property determines the positioning method of an element. The most common values are static, relative, absolute, and fixed.

9. What is the CSS z-index property?

The CSS z-index property determines the stacking order of positioned elements. Elements with a higher z-index value will appear on top of elements with a lower value.

10. What is the CSS box-sizing property?

The CSS box-sizing property determines how the width and height of an element are calculated. The most common values are content-box and border-box.

11. What is the CSS transition property?

The CSS transition property allows for smooth animations between different states of an element. It specifies which CSS properties should be transitioned, how long the transition should take, and what easing function to use.

12. What is the CSS transform property?

The CSS transform property allows for 2D and 3D transformations of an element. It can be used to rotate, scale, skew, and translate elements.

13. What is the CSS media query?

The CSS media query allows for different styles to be applied to an element based on the device or screen size it is being viewed on. This is commonly used for creating responsive designs that adapt to different devices.

14. What is the CSS pseudo-class?

A CSS pseudo-class is a keyword added to a selector that specifies a special state of the element. Examples include :hover, :active, and :focus.

15. What is the CSS pseudo-element?

A CSS pseudo-element is a keyword added to a selector that creates a new element that can be styled separately from the original element. Examples include ::before and ::after.

16. What is the CSS box-shadow property?

The CSS box-shadow property adds a shadow to an element. It specifies the shadow's position, size, and color.

17. What is the CSS text-shadow property?

The CSS text-shadow property adds a shadow to the text of an element. It specifies the shadow's position, size, and color.

18. What is the CSS background property?

The CSS background property sets the background color and/or image of an element. It can be used to create patterns, gradients, and other effects.

19. What is the CSS opacity property?

The CSS opacity property sets the opacity (transparency) of an element. It can be used to create subtle or dramatic effects.

20. What is the CSS overflow property?

The CSS overflow property specifies how an element should handle content that overflows its bounds. Common values include visible, hidden, scroll, and auto.

21. What is the CSS flexbox layout?

The CSS flexbox layout is a powerful layout system for creating flexible and responsive designs. It uses a container and one or more flex items to define the layout.

22. What is the CSS grid layout?

The CSS grid layout is a layout system that allows for precise placement of elements on a grid. It uses a container and one or more grid items to define the layout.

23. What is the CSS pseudo-selector ::first-child?

The CSS pseudo-selector ::first-child selects the first child element of its parent. It can be used to apply styles specifically to the first child element.

24. What is the CSS pseudo-selector ::nth-child?

The CSS pseudo-selector ::nth-child selects an element based on its position within its parent. It can be used to apply styles to every nth child element.

25. What is the CSS pseudo-selector ::last-child?

The CSS pseudo-selector ::last-child selects the last child element of its parent. It can be used to apply styles specifically to the last child element.

26. What is the CSS clear property?

The CSS clear property specifies whether an element should be placed next to floating elements or clear them. Common values include left, right, both, and none.

27. What is the CSS max-width property?

The CSS max-width property sets the maximum width of an element. It can be used to ensure that an element does not exceed a certain width.

28. What is the CSS min-height property?

The CSS min-height property sets the minimum height of an element. It can be used to ensure that an element has a certain minimum height.

29. What is the CSS border-radius property?

The CSS border-radius property sets the rounding of the corners of an element. It can be used to create rounded corners, circles, and other shapes.

30. What is the CSS text-align property?

The CSS text-align property sets the horizontal alignment of text within an element. Common values include left, right, center, and justify.

31. What is the CSS vertical-align property?

The CSS vertical-align property sets the vertical alignment of an inline element within a line of text. Common values include top, middle, and bottom.

32. What is the CSS font-family property?

The CSS font-family property sets the font family of an element. It can be used to specify custom fonts or fallback fonts.

33. What is the CSS font-size property?

The CSS font-size property sets the size of the font of an element. It can be specified in pixels, ems, or other units.

34. What is the CSS font-weight property?

The CSS font-weight property sets the weight (boldness) of the font of an element. Common values include normal, bold, and bolder.

35. What is the CSS text-decoration property?

The CSS text-decoration property sets the decoration of text within an element. Common values include underline, overline, and line-through.

36. What is the CSS line-height property?

The CSS line-height property sets the height of a line of text within an element. It can be specified in pixels, ems, or other units.

37. What is the CSS background-size property?

The CSS background-size property sets the size of the background image of an element. It can be used to scale the image to fit the element or to cover the element entirely.

38. What is the CSS transition property?

The CSS transition property sets the duration and type of a transition between two states of an element. It can be used to create smooth animations and effects.

39. What is the CSS transform property?

The CSS transform property applies a 2D or 3D transformation to an element. It can be used to rotate, scale, skew, and translate elements.

40. What is the CSS perspective property?

The CSS perspective property sets the perspective (depth) of a 3D element. It can be used to create 3D effects and depth perception.

41. What is the CSS animation property?

The CSS animation property sets the duration, timing function, and other properties of an animation applied to an element. It can be used to create complex animations and effects.

42. What is the CSS box-shadow property?

The CSS box-shadow property sets a shadow effect around an element. It can be used to create depth, emphasis, and other effects.

43. What is the CSS display property?

The CSS display property sets how an element should be displayed. Common values include block, inline, and none.

44. What is the CSS position property?

The CSS position property sets how an element should be positioned within its container. Common values include static, relative, absolute, and fixed.

45. What is the CSS z-index property?

The CSS z-index property sets the stacking order of elements with respect to each other. It can be used to control which elements appear on top of others.

46. What is the CSS cursor property?

The CSS cursor property sets the appearance of the cursor when it is over an element. It can be used to indicate the type of interaction that is possible with the element.

47. What is the CSS user-select property?

The CSS user-select property sets whether text can be selected within an element. It can be used to prevent users from selecting text or to allow them to select only certain parts of the text.

48. What is the CSS pointer-events property?

The CSS pointer-events property sets whether an element should respond to mouse and touch events. It can be used to make an element unclickable or to allow events to pass through an element.

49. What is the CSS filter property?

The CSS filter property applies visual effects to an element, such as blurring, brightness, and color adjustments. It can be used to create interesting and creative effects.

50. What is the CSS word-wrap property?

The CSS word-wrap property sets how long words should be allowed to continue without breaking onto a new line. It can be used to ensure that long words do not break the layout of an element.  

51. What is the CSS box-sizing property?

The CSS box-sizing property sets how the width and height of an element are calculated. It can be used to control whether padding and border are included in the width and height of an element.

52. What is the CSS overflow property?

The CSS overflow property sets what happens when content overflows an element's box. It can be used to create scrollable areas and to control the visibility of overflowed content.

53. What is the CSS flexbox layout?

The CSS flexbox layout is a layout model that allows for flexible and responsive layouts. It can be used to easily align and distribute elements within a container.

54. What is the CSS grid layout?

The CSS grid layout is a layout model that allows for complex and multi-dimensional layouts. It can be used to create responsive designs and to easily align and position elements.

55. What is the CSS specificity of a selector?

The CSS specificity of a selector determines which styles will be applied to an element when multiple selectors target the same element. It is calculated based on the number and type of selectors used.

56. What is the CSS float property?

The CSS float property sets how an element should be floated within its container. It can be used to create text wrapping and to position elements side-by-side.

57. What is the CSS clear property?

The CSS clear property sets whether an element should be positioned below or above floated elements. It can be used to control the layout of elements that follow floated elements.

58. What is the CSS media query?

The CSS media query is a feature that allows for different styles to be applied to an element based on the device or screen size. It can be used to create responsive and mobile-friendly designs.

59. What is the CSS pseudo-class?

The CSS pseudo-class is a special class that is used to target specific states of an element, such as when it is hovered over or focused. It can be used to create interactive and dynamic effects.

60. What is the CSS vendor prefix?

The CSS vendor prefix is a prefix added to a CSS property or value to indicate which browser vendor it is intended for. It can be used to ensure compatibility with different browsers and versions.

61. What is the CSS specificity hierarchy?

The CSS specificity hierarchy is the order in which CSS selectors are evaluated to determine which styles should be applied to an element. The hierarchy starts with the type selector, followed by the class selector, then the ID selector, and finally the inline style.

62. What is the difference between absolute and relative positioning in CSS?

Absolute positioning in CSS positions an element relative to its nearest positioned ancestor, while relative positioning positions an element relative to its normal position. Absolute positioning is often used for creating overlay elements, while relative positioning is often used for fine-tuning the layout of elements.

63. What is the CSS :nth-child() selector?

The CSS :nth-child() selector is a pseudo-class selector that targets elements based on their position within their parent element. It can be used to target specific elements or groups of elements.

64. What is the CSS transition property?

The CSS transition property is used to specify the transition effect when a CSS property changes its value. It can be used to create smooth and dynamic effects when elements are hovered over or clicked.

65. What is the CSS transform property?

The CSS transform property is used to apply transformations to elements, such as scaling, rotating, and translating. It can be used to create visual effects and to fine-tune the layout of elements.

66. What is the CSS animation property?

The CSS animation property is used to create animations for elements. It can be used to create complex and dynamic effects using keyframes and timing functions.

67. What is the CSS content property?

The CSS content property is used to add content before or after an element using the ::before and ::after pseudo-elements. It can be used to add decorative elements, such as icons or background images, to elements.

68. What is the CSS filter property?

The CSS filter property is used to apply visual effects, such as blurring or color shifting, to elements. It can be used to create unique and engaging designs.

69. What is the CSS visibility property?

The CSS visibility property sets whether an element should be visible or hidden. It can be used to create toggling effects or to hide elements when they are not needed.

70. What is the CSS opacity property?

The CSS opacity property sets the opacity level of an element. It can be used to create transparent or semi-transparent elements.

71. What is the CSS counter property?

The CSS counter property is used to create and increment counters that can be used to number elements or create custom counters. It can be used to create unique and dynamic designs.

72. What is the CSS line-height property?

The CSS line-height property sets the height of a line of text. It can be used to adjust the spacing between lines of text and to create visually appealing typography.

73. What is the CSS font-face rule?

The CSS font-face rule is used to specify custom fonts that can be used on a website. It can be used to create unique and engaging typography.

74. What is the CSS text-shadow property?

The CSS text-shadow property is used to add shadows to text. It can be used to create subtle and elegant designs.

75. What is the CSS outline property?

The CSS outline property sets an outline around an element, similar to a border, but without affecting the layout of the element. It can be used to create visual emphasis and to highlight elements.