Answers for "horizontal height css"

css align items vertical center

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

css center

// example 1 
div { display: grid; place-items: center; }

// example 3
div{ display:flex; align-items:center; }

// example 3
div { width: 100%; margin: 0 auto; }

css align center

.center {
  margin: auto;
  width: 50%;
  border: 3px solid green;
  padding: 10px;
}