Answers for "how to center an html box"

center a div in css

.container {
  display: flex;
  justify-content: center;
  align-items: center;
}

different ways to center a div

/* Centering an element without flexbox */
.parent-element {
  position: relative;
}

.child-element {
	position: absolute;
  	left: 50%;
  	top: 50%;
  	transform: translate(-50%, -50%);
}

/* Centering an element using flexbox */
.parent-element {
	display: flex;
  	align-items: center;
  	justify-content: center;
}