CSS Cheat Sheet 2026

The 30 highest-yield CSS facts, distilled from real exam questions. Print it, save it as a PDF, or study it here — free, no sign-up.

1. We don't have to reapply style information throughout the document or to external documents when using Inline Style. → A) False
2. Which CSS methodology uses Block, Element, and Modifier naming to keep stylesheets maintainable? → BEM
3. Which CSS property controls the space between an element's content area and its border? → padding
4. Which CSS property prevents images from overflowing their container on small screens? → max-width: 100%
5. A style can be applied to just one tag by using a ___________ → id rule
6. Which CSS layout module is best suited for two-dimensional row and column layouts? → CSS Grid
7. Select a CSS property for collapsing the borders between table cells. → border-collapse
8. What does 'inset: 0' shorthand set on a positioned element? → top, right, bottom, and left all to 0
9. What does a 'value proposition' communicate in strategic planning? → The unique benefit an organization offers its customers
10. Which of the following are Webkit's CSS Extension Prefixes? → -webkit
11. What does an HTML table's colspan attribute do? → Makes a cell span multiple columns
12. How do you add a CSS comment? → /* comment */
13. What does the hexadecimal color value #FFFFFF represent? → White
14. Which keyword value for `animation-iteration-count` causes an animation to repeat indefinitely? → infinite
15. What does scenario planning help an organization prepare for? → Multiple plausible future conditions and uncertainties
16. Which compliance standard governs web accessibility most widely referenced for CSS? → WCAG
17. Which value will determine the width of the viewport? → color-index
18. Which CSS property determines how the width and height of an element are calculated relative to padding and border? → box-sizing
19. Which CSS feature helps reduce repetition and improve consistency of values? → Custom properties (CSS variables)
20. Which CSS function allows you to perform calculations to determine property values? → calc()
21. What does the CSS custom property fallback syntax var(--x, blue) mean? → Use --x, or blue if --x is invalid or undefined
22. Which of the following is the CSS3 HSL value with a fourth value to determine the color's alpha channel value to define the element's opacity? → HSLa Color
23. Which of these is a valid way to apply CSS directly to one HTML element? → Inline style attribute
24. Which CSS property controls the space between the content and the border of an element? → padding
25. Which of the following functions is used by the filter property to change the brightness of an element's color? → brightness()
26. What is the result of setting 'margin: 0 auto' on a block element with a fixed width? → It horizontally centers the element
27. Which value makes a flex container wrap items onto multiple lines? → flex-wrap: wrap
28. Which property and value enable a sticky header that stays at the top when scrolling? → position: sticky; top: 0;
29. Which of the following best describes browsing without the use of stylesheets? → CSS OFF/Images ON
30. Identify the CSS property that defines the border's bottom-left corner shape. → border-bottom-left-radius