Answers for "how to align content vertically center"

css align items vertical center

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

css center div vertically

/* center vertically */
/* No Flexbox */
.parent {
  position: relative;
}
.child {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
}



/* With Flexbox */

.parent {
  display: flex;
  flex-direction: column;
  justify-content: center;
}