# What is VH/VW (viewport height/ viewport width) in CSS?

It’s a CSS unit used to measure the height and width in percentage with respect to the viewport. It is used mainly in responsive design techniques. The measure VH is equal to 1/100 of the height of the viewport. If the height of the browser is 1000px, 1vh is equal to 10px. Similarly, if the width is 1000px, then 1 vw is equal to 10px.

vw: Viewport width (1vw = 1% of the viewport width)

# Difference between reset vs normalize CSS?. How do they differ?

Reset CSS: CSS resets aim to remove all built-in browser styling. For example margins, paddings, font-sizes of all elements are reset to be the same.

Normalize CSS: Normalize CSS aims to make built-in browser styling consistent across browsers. It also corrects bugs for common browser dependencies.

# What does DOM reflow occur?

Reflow occurs when:

Insert, remove or update an element in the DOM.
Modify content on the page, e.g. the text in an input box.
Move a DOM element.
Animate a DOM element.
Take measurements of an element such as offsetHeight or getComputedStyle.
Change a CSS style.